Vincent Craig

Measurement of no-slip and slip boundary conditions in confined Newtonian fluids using atomic force microscopy

Publisher: Royal Society of Chemistry (RSC)

Date: 2009

DOI: 10.1039/B908142A

Abstract: We report measurements of slip length at smooth and rough hydrophilic silica surfaces, using the hydrodynamic force measurement atomic force microscope (AFM). There has been some debate in the literature as to whether the boundary condition between a solid and a wetting fluid is one of no-slip or partial-slip in particular the results of Neto et al. (C. Neto, V. S. J. Craig and D. R. M. Williams, Eur. Phys. J. E, 2003, 12, S71-S74) and of Honig and Ducker (C. D. F. Honig and W. A. Ducker, Phys. Rev. Lett., 2007, 98, 028305) are inconsistent. Unexpectedly, the AFM cantilever geometry leads to a different measurement of hydrodynamic drainage force. Rectangular cantilevers give results consistent with a no-slip boundary condition on smooth and rough surfaces, while v-shaped cantilever measurements show variability and can produce a finding of apparent partial-slip, consistent with earlier results in the literature. Possible reasons for the discrepancy are discussed. Equilibrium force measurements show no cantilever shape dependence. We conclude that the appropriate boundary condition for aqueous solutions on smooth and nanoscale-rough hydrophilic surfaces is one of no-slip.

Surface Forces and Rheology of Titanium Dioxide in the Presence of Dicarboxylic Acids: From Molecular Interactions to Yield Stress

Publisher: American Chemical Society (ACS)

Date: 31-01-2017

DOI: 10.1021/ACS.LANGMUIR.6B04314

Abstract: The surface forces and yield stress of titanium dioxide were measured in the presence of dicarboxylic acids in order to understand the molecular basis for the observed rheological response. The yield stress was measured using the static vane technique, and the surface forces were characterized using an atomic force microscope. The trans and cis isomers of butenedioic acid (fumaric and maleic acids, respectively) were chosen as the relative orientation of the carboxylic groups differs substantially. This enables us to test the hypothesis that an increase in adhesion leads to an increase in yield stress as a consequence of the dicarboxylic acids participating in highly directed bridging. Unlike fumaric acid, maleic acid caused a yield stress reduction in the titanium dioxide suspensions. Surface force measurements between approaching surfaces found that at low pH, fumaric and maleic acids did not induce any additional attraction between the titanium dioxide surfaces. However, significant differences in adhesion were observed, which can be explained in terms of the configuration of the acids at the surface. The observations are consistent with highly directed bridging in the presence of fumaric acid but not in the presence of maleic acid due to the molecular architecture of the dicarboxylic acids.

Tackling change in mental health service delivery: A qualitative evaluation of a lifestyle program targeting mental health staff – Keeping our Staff in Mind (KoSiM)

Publisher: Wiley

Date: 15-07-2022

DOI: 10.1002/HPJA.633

Abstract: People with severe mental illness have adverse health outcomes compared to the general population. Lifestyle interventions are effective in improving health outcomes in this population. Current cultural processes in mental health services do not generally incorporate physical health care practices. Innovative education is required to improve knowledge and confidence of staff in the delivery of preventative health measures. The Keeping our Staff in Mind (KoSiM) program delivered a brief lifestyle intervention to mental health staff. A qualitative analysis following the Standards for Reporting Qualitative Research was undertaken. Semi‐structured interviews designed to elicit information about the acceptability of the program and the impact of the intervention on participants' personal and professional lives. The interviews were analysed using thematic analysis, with coding independently developed and reviewed by three authors. Of the 103 eligible participants, 75 were interviewed. Responses revealed four main themes: (i) positive changes in clinician's approach to physical health care, (ii) improvements in attitudes to self‐care and family wellbeing, (iii) positive changes in workplace culture associated with physical health care delivery and (iv) high levels of acceptability of the program. The KoSiM model may be useful in other settings as a means of changing the culture of mental health services to better integrate physical health care as a core part of mental health service provision. A novel approach using staff focussed lifestyle interventions model may cut through the resistance that is encountered when implementing proven methods of clinical intervention where cultural barriers exist.

Cardio-metabolic risk and its management in a cohort of clozapine-treated outpatients.

Publisher: Elsevier BV

Date: 09-2018

DOI: 10.1016/J.SCHRES.2018.02.035

Abstract: To comprehensively assess cardio-metabolic risk factors and their management in a large s le of outpatients treated with clozapine. Observational cross-sectional study of all clozapine users attending specialized clozapine monitoring outpatient clinics in three public hospitals in Sydney, Australia were approached to participate over the one-year period 01/10/2015-30/09/2016. Cardio-metabolic risk factors including metabolic syndrome, risk for future development of diabetes, smoking, physical activity, nutrition, and prescribed medications were assessed at face-to-face interview and through medical record review. Among patients who had cardio-metabolic risk factors, the proportion receiving appropriate management was assessed. Of 451 registered clozapine clinic attenders, 92.2% completed questionnaires and anthropometric measurements. 58.3% met criteria for metabolic syndrome. 79.6% were overweight or obese. 55.9% had blood pressure meeting metabolic syndrome criteria. 46.6% had elevated fasting blood glucose and 55.2% had elevated blood triglycerides. 43.6% were current smokers. Only 10% achieved recommended weekly physical activity levels. Unhealthy food categories were highly consumed. 32.1% were on additional antipsychotics. In the majority of in iduals, cardio-metabolic risk factors were untreated or under-treated. Clozapine use was associated with very high rates of cardiovascular and metabolic risk factors, which were frequently under-treated. Management of both physical and mental health should be prioritized. Polypharmacy should be rationalized. Future research should investigate the effectiveness of smoking cessation and lifestyle interventions in this high-risk population.

Hydrophobic Attraction Measured between Asymmetric Hydrophobic Surfaces

Publisher: American Chemical Society (ACS)

Date: 28-02-2018

DOI: 10.1021/ACS.LANGMUIR.7B04246

Abstract: The interaction forces between silica surfaces modified to different degrees of hydrophobicity were measured using colloidal probe atomic force microscopy (AFM). A highly hydrophobic silica particle was prepared with octadecyltrichlorosilane (OTS), and the interaction forces were measured against silica substrates modified to produce surfaces of varying hydrophobicity. The interaction forces between the highly hydrophobic particle and a completely hydrophilic silicon wafer surface fitted well to the DLVO theory, indicating that no additional (non-DLVO) forces act between the surfaces. When the silicon wafer surface was treated to produce a contact angle of water on surface of 40°, an additional attractive force that is longer ranged than the van der Waals force was observed between the surfaces. The range and magnitude of the attractive force increase with the contact angle of water on the substrate. Beyond the effect on the contact angle, the hydrocarbon chain length and the terminal groups of hydrophobic layer on the substrate only have a minor effect on the magnitude of the force, even when the substrate is terminated with polar carboxyl groups, provided the hydrophobicity of the other surface is high.

The Link between Ion Specific Bubble Coalescence and Hofmeister Effects Is the Partitioning of Ions within the Interface

Publisher: American Chemical Society (ACS)

Date: 21-01-2010

DOI: 10.1021/LA9039495

Abstract: Specific ion effects are ubiquitous in soft matter systems and are most readily observed at high salt concentrations where long-range electrostatic forces are screened. In biological systems, ion-specificity is universal and is necessary to introduce the complexity required to carry out the processes of life. Many specific ion effects fall within the Hofmeister paradigm, whereby the strengths of action of the anions and cations follow a well-defined order, independent of the counterion. In contrast, specific ion effects evident in bubble coalescence inhibition depend on the combination of ions, and this phenomenon can be codified using simple ion-combining rules not evident in the Hofmeister systems. Here we show that these disparate specific ion effects have the same origin: They result from the variation in ion affinity for the solution interface. Equilibrium affinities explain Hofmeister effects, whereas we argue that the cation/anion combination controls bubble coalescence inhibition because of dynamic interfacial processes occurring at the more deformable gas-water interface.

Black-hole spectroscopy, the no-hair theorem, and GW150914: Kerr versus Occam

Publisher: American Physical Society (APS)

Date: 21-01-2021

DOI: 10.1103/PHYSREVD.103.024041

Inhibition of bubble coalescence by electrolytes in binary mixtures of dimethyl sulfoxide and propylene carbonate

Publisher: American Chemical Society (ACS)

Date: 11-06-2009

DOI: 10.1021/LA901199H

Abstract: We have investigated the effect of solvent composition on inhibition of bubble coalescence by electrolytes in binary mixtures of dimethyl sulfoxide (DMSO) and propylene carbonate (PC). Unlike most mixtures, combinations of DMSO and PC exhibit minimal foaming over all compositions (with the strongest effect being at 25% PC by volume) thus, the influence of electrolytes can be investigated. Both LiBr and KSCN at moderate concentrations inhibit bubble coalescence at all solvent compositions. However, the concentration of electrolyte required to inhibit coalescence was in both cases a minimum at the PC(v/v) of 25%. The surface tension of electrolyte solutions in the mixed solvents indicates that the gradient in surface tension is not correlated with coalescence inhibition and therefore inhibition cannot be attributed to surface elasticity. We have also studied the inhibition of bubble coalescence by HCl at different solvent compositions. HCl is strongly inhibitory in DMSO but only weakly so in PC. We have found that HCl exhibits strong inhibition behavior at all mixtures studied. All electrolytes studied were most effective at inhibiting bubble coalescence at the PC(v/v) of 25%, indicating that the interactions between solvent molecules strongly determine the influence of electrolyte on coalescence inhibition. We propose that the formation of solvent complexes between DMSO and PC results in an increase in surface viscosity and the presence of electrolytes further lifies this effect.

The effect of surfactant adsorption on liquid boundary slippage

Publisher: Elsevier BV

Date: 08-2004

DOI: 10.1016/J.PHYSA.2004.03.044

The hydrophobic force: Nanobubbles or polymeric contaminant?

Publisher: Elsevier BV

Date: 08-2004

DOI: 10.1016/J.PHYSA.2004.03.043

Improved Cleaning of Hydrophilic Protein-Coated Surfaces using the Combination of Nanobubbles and SDS

Publisher: American Chemical Society (ACS)

Date: 20-01-2009

DOI: 10.1021/AM800150P

Abstract: The use of nanobubbles, the common surfactant sodium dodecyl sulfate (SDS), and nanobubbles in combination with SDS as cleaning agents to remove lysozyme from the solid-liquid interface has been investigated using a quartz crystal microbalance on both hydrophobic and hydrophilic surfaces. On the hydrophobic surface, significant amounts of protein remained on the surface after 10 cycles of nanobubble treatment for 10 s periods in phosphate buffer. The cleaning efficiency of SDS was far superior and was shown to remove approximately 90% of the protein. The use of nanobubbles in combination with SDS failed to improve the cleaning efficiency further. On the other hand, lysozyme on the hydrophilic surface cannot be removed effectively by either 10 cycles of cleaning with nanobubbles or 10 cycles of cleaning with SDS. Nevertheless, the protein can be removed completely after 6 cycles of cleaning with nanobubbles in combination with SDS.

Physical properties of nanobubbles on hydrophobic surfaces in water and aqueous solutions

Publisher: American Chemical Society (ACS)

Date: 26-04-2006

DOI: 10.1021/LA0601814

Abstract: In recent years there has been an accumulation of evidence for the existence of nanobubbles on hydrophobic surfaces in water, despite predictions that such small bubbles should rapidly dissolve because of the high internal pressure associated with the interfacial curvature and the resulting increase in gas solubility. Nanobubbles are of interest among surface scientists because of their potential importance in the long-range hydrophobic attraction, microfluidics, and adsorption at hydrophobic surfaces. Here we employ recently developed techniques designed to induce nanobubbles, coupled with high-resolution tapping-mode atomic force microscopy (TM-AFM) to measure some of the physical properties of nanobubbles in a reliable and repeatable manner. We have reproduced the earlier findings reported by Hu and co-workers. We have also studied the effect of a wide range of solutes on the stability and morphology of these deliberately formed nanobubbles, including monovalent and multivalent salts, cationic, anionic, and nonionic surfactants, as well as solution pH. The measured physical properties of these nanobubbles are in broad agreement with those of macroscopic bubbles, with one notable exception: the contact angle. The nanobubble contact angle (measured through the denser aqueous phase) was found to be much larger than the macroscopic contact angle on the same substrate. The larger contact angle results in a larger radius of curvature and a commensurate decrease in the Laplace pressure. These findings provide further evidence that nanobubbles can be formed in water under some conditions. Once formed, these nanobubbles remain on hydrophobic surfaces for hours, and this apparent stability still remains a well-recognized mystery. The implications for s le preparation in surface science and in surface chemistry are discussed.

Superhydrophobic and Superoleophilic Boron Nitride Nanotube-Coated Stainless Steel Meshes for Oil and Water Separation

Publisher: Wiley

Date: 08-11-2014

DOI: 10.1002/ADMI.201300002

Artificial neural networks for the prediction of solvation energies based on experimental and computational data

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0CP03701J

Abstract: We present a machine learning approach based on artificial neural networks for the prediction of ion pair solvation energies.

APC/C^Fzr/Cdh1 promotes cell cycle progression during the Drosophila endocycle

Publisher: The Company of Biologists

Date: 15-04-2008

DOI: 10.1242/DEV.016295

Abstract: The endocycle is a commonly observed variant cell cycle in which cells undergo repeated rounds of DNA replication with no intervening mitosis. How the cell cycle machinery is modified to transform a mitotic cycle into endocycle has long been a matter of interest. In both plants and animals, the transition from the mitotic cycle to the endocycle requires Fzr/Cdh1, a positive regulator of the Anaphase-Promoting Complex/Cyclosome (APC/C). However, because many of its targets are transcriptionally downregulated upon entry into the endocycle, it remains unclear whether the APC/C functions beyond the mitotic/endocycle boundary. Here, we report that APC/CFzr/Cdh1 activity is required to promote the G/S oscillation of the Drosophila endocycle. We demonstrate that compromising APC/C activity, after cells have entered the endocycle, inhibits DNA replication and results in the accumulation of multiple APC/C targets, including the mitotic cyclins and Geminin. Notably, our data suggest that the activity of APC/CFzr/Cdh1 during the endocycle is not continuous but is cyclic,as demonstrated by the APC/C-dependent oscillation of the pre-replication complex component Orc1. Taken together, our data suggest a model in which the cyclic activity of APC/CFzr/Cdh1 during the Drosophilaendocycle is driven by the periodic inhibition of Fzr/Cdh1 by Cyclin E/Cdk2. We propose that, as is observed in mitotic cycles, during endocycles,APC/CFzr/Cdh1 functions to reduce the levels of the mitotic cyclins and Geminin in order to facilitate the relicensing of DNA replication origins and cell cycle progression.

Do hydration forces play a role in thin film drainage and rupture observed in electrolyte solutions?

Publisher: Elsevier BV

Date: 12-2011

DOI: 10.1016/J.COCIS.2011.04.003

A mobile gas-water interface in electrolyte solutions

Publisher: American Chemical Society (ACS)

Date: 09-09-2008

DOI: 10.1021/JP8067969

Quantitative Solvation Energies from Gas-Phase Calculations: First-Principles Charge Transfer and Perturbation Approaches

Publisher: American Chemical Society (ACS)

Date: 14-03-2023

DOI: 10.1021/ACS.JPCB.2C08907

A History of Nanobubbles

Publisher: American Chemical Society (ACS)

Date: 14-09-2016

DOI: 10.1021/ACS.LANGMUIR.6B02489

Abstract: We follow the history of nanobubbles from the earliest experiments pointing to their existence to recent years. We cover the effect of Laplace pressure on the thermodynamic stability of nanobubbles and why this implies that nanobubbles are thermodynamically never stable. Therefore, understanding bubble stability becomes a consideration of the rate of bubble dissolution, so the dominant approach to understanding this is discussed. Bulk nanobubbles (or fine bubbles) are treated separately from surface nanobubbles as this reflects their separate histories. For each class of nanobubbles, we look at the early evidence for their existence, methods for the production and characterization of nanobubbles, evidence that they are indeed gaseous, or otherwise, and theories for their stability. We also look at applications of both surface and bulk nanobubbles.

Surface forces: Surface roughness in theory and experiment

Publisher: AIP Publishing

Date: 22-04-2014

DOI: 10.1063/1.4871412

Abstract: A method of incorporating surface roughness into theoretical calculations of surface forces is presented. The model contains two chief elements. First, surface roughness is represented as a probability distribution of surface heights around an average surface height. A roughness-averaged force is determined by taking an average of the classic flat-surface force, weighing all possible separation distances against the probability distributions of surface heights. Second the model adds a repulsive contact force due to the elastic contact of asperities. We derive a simple analytic expression for the contact force. The general impact of roughness is to lify the long range behaviour of noncontact (DLVO) forces. The impact of the elastic contact force is to provide a repulsive wall which is felt at a separation between surfaces that scales with the root-mean-square (RMS) roughness of the surfaces. The model therefore provides a means of distinguishing between “true zero,” where the separation between the average centres of each surface is zero, and “apparent zero,” defined by the onset of the repulsive contact wall. A normal distribution may be assumed for the surface probability distribution, characterised by the RMS roughness measured by atomic force microscopy (AFM). Alternatively the probability distribution may be defined by the histogram of heights measured by AFM. Both methods of treating surface roughness are compared against the classic smooth surface calculation and experimental AFM measurement.

Macroscopically flat and smooth superhydrophobic surfaces: Heating induced wetting transitions up to the Leidenfrost temperature

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/B924965F

Abstract: We present an investigation of the change in wettability of water droplets on 3 different flat, smooth substrates with an elevation in temperature. Two methods were employed. In the first method the droplet was placed on the substrate before it was heated and in the second method the droplets were induced to fall onto a preheated substrate. We find that the intrinsic wettability of the surface is important and that fundamentally different behavior is observed on a hydrophobic surface relative to hydrophilic surfaces. For the hydrophobic surface and employing the first method, we have observed three different regimes over the temperature range of 65 degrees C to 270 degrees C. In regime I (65 degrees C to 110 degrees C), the contact angle of water droplets exhibit a slight decrease from 108 degrees to 105 degrees and an accompanying significant decrease in droplet lifetime (tau) from approximately 111 s to approximately 30 s is observed. In regime II (120 degrees C to 190 degrees C), tau remains constant at approximately 20 s however the contact angle significantly increases from 127 degrees to 158 degrees--that is we enter a superhydrophobic regime on a flat surface. In this regime the droplet remains stationary on the surface. Regime III (210 degrees C to 270 degrees C), is the Leidenfrost regime in which the water droplet exhibits a rapid motion on the solid surface with a contact angle higher than 160 degrees. In comparison, the wetting behavior of a water droplet on two relatively hydrophilic surfaces (Au and GaAs) have also been investigated as a function of temperature. Here no wetting transition is observed from 65 degrees C up to 365 degrees C. In the second method, the wetting behavior on the hydrophobic surface is similar to that observed in the first method for temperatures below the Leidenfrost temperature and the water droplet rebounds from the solid surface at higher temperatures. Additionally, the Leidenfrost phenomenon can be observed above 280 degrees C for the hydrophilic surfaces.

Superhydrophobic and Superoleophilic Porous Boron Nitride Nanosheet/Polyvinylidene Fluoride Composite Material for Oil-Polluted Water Cleanup

Publisher: Wiley

Date: 03-11-2014

DOI: 10.1002/ADMI.201400267

Effectiveness of a brief lifestyle intervention targeting mental health staff: Analysis of physical fitness and activity in the Keeping Our Staff in Mind study

Publisher: BMJ

Date: 07-2020

DOI: 10.1136/BMJSEM-2020-000761

Abstract: People with mental illness die on average 15 years less than the general population, primarily to cardiometabolic disease. Lifestyle interventions are effective in reducing cardiometabolic risk but are not routinely provided to mental health consumers. Lifestyle interventions targeting mental health staff may be beneficial in changing culture surrounding physical health and subsequently improving consumer outcomes. This study examines exercise and fitness outcomes of a targeted lifestyle intervention directed at Australian mental health staff. A pragmatic single-arm intervention study was conducted within an Australian public mental health service. Mental health staff were provided a five-session in idualised lifestyle intervention (incorporating exercise and nutritional counselling) over 5 weeks. Two waves of the programme were delivered between 2015 and 2016. This paper examines the exercise and fitness outcomes of the second wave of the study. Participants were assessed at baseline and at a 16-week follow-up. The primary exercise outcome was a measurement of cardiorespiratory fitness. Secondary outcomes included self-reported physical activity and a measurement of handgrip strength. A total of 106 staff participated in this component of the study. Cardiorespiratory fitness increased significantly from baseline to follow-up (p .001). Significant improvements to physical activity occurred with decreases in sedentary time (p .0005) and increases in moderate-to-vigorous physical activity (p .005). Lifestyle interventions incorporating exercise counselling may improve the physical health of mental health staff. Such strategies may be effective in improving culture surrounding physical health and/or increasing the effectiveness of lifestyle interventions targeting mental health consumers.

Synthesis and chemical modifications of in-situ grown anatase TiO2 microspheres with isotropically exposed {0 0 1} facets for superhydrophobic and self-cleaning properties

Publisher: Elsevier BV

Date: 12-2015

DOI: 10.1016/J.APSUSC.2015.09.179

Effect of Dissolved Gas and Salt on the Hydrophobic Force between Polypropylene Surfaces

Publisher: American Chemical Society (ACS)

Date: 08-1994

DOI: 10.1021/LA00020A039

Electrochemical Principles for Active Control of Liquids on Submillimeter Scales

Publisher: American Association for the Advancement of Science (AAAS)

Date: 1999

DOI: 10.1126/SCIENCE.283.5398.57

Abstract: Electrochemical methods were combined with redox-active surfactants to actively control the motions and positions of aqueous and organic liquids on millimeter and smaller scales. Surfactant species generated at one electrode and consumed at another were used to manipulate the magnitude and direction of spatial gradients in surface tension and guide droplets of organic liquids through simple fluidic networks. Solid microparticles could be transported across unconfined surfaces. Electrochemical control of the position of surface-active species within aqueous films of liquid supported on homogeneous surfaces was used to direct these films into periodic arrays of droplets with deterministic shapes and sizes.

Measurement of long range attractive forces between hydrophobic surfaces produced by vapor phase adsorption of palmitic acid

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7SM01563A

Abstract: The electrostatic interaction between a patch of bilayer and the bare surface gives rise to the attraction between these hydrophobic surfaces.

Adsorption of the Cationic Surfactant Cetyltrimethylammonium Bromide to Silica in the Presence of Sodium Salicylate: Surface Excess and Kinetics

Publisher: American Chemical Society (ACS)

Date: 05-10-2009

DOI: 10.1021/LA901889M

Abstract: The adsorption of cetyltrimethylammonium bromide (CTAB) to silica in the presence of sodium salicylate has been investigated using atomic force microscopy, optical reflectometry, and a quartz crystal microbalance. Salicylate is found to have a dramatic influence on surface adsorption in terms of the kinetics, surface excess, structure of adsorbed aggregates and the mechanical rigidity of the adsorbed film. This is consistent with the bulk solution behavior of more concentrated CTAB-salicylate solutions and reflects the higher local concentration induced by adsorption to the silica surface. Slow adsorption kinetics are found over a wide range of concentrations below the critical micelle concentration.

Surface Nanobubbles in Nonaqueous Media: Looking for Nanobubbles in DMSO, Formamide, Propylene Carbonate, Ethylammonium Nitrate, and Propylammonium Nitrate

Publisher: American Chemical Society (ACS)

Date: 13-07-2015

DOI: 10.1021/ACSNANO.5B02915

Abstract: Surface nanobubbles produced by supersaturation during the exchange of ethanol for water are routinely observed on hydrophobic surfaces, are stable for days, and have contact angles that are very much greater than observed macroscopically. Here, we test the hypothesis that nanobubbles can also be observed in nonaqueous solvents in order to ascertain if their anomalous lifetimes and contact angles are related to properties of the solvent. Nanobubbles were seen in the protic solvents formamide, ethylammonium nitrate, and propylammonium nitrate, but not in propylene carbonate or dimethyl sulfoxide. Solvents in which nanobubbles were observed exhibit a three-dimensional hydrogen-bonding network. Like in aqueous systems, the nanobubbles were stable for days and exhibited high contact angles (∼165°).

Roughness of Microspheres for Force Measurements

Publisher: American Chemical Society (ACS)

Date: 14-06-2008

DOI: 10.1021/LA800664F

Abstract: We have investigated the morphology and surface roughness of several commercially available microspheres to determine their suitability for force measurements using the atomic force microscope. The roughness varies considerably, depending on sphere size and material, ranging from nearly ideally flat up to micrometer-sized features. Because surface roughness significantly influences the magnitude and accuracy of measurement of surface forces, the results presented here should be helpful for colloid physicists and in particular for those performing force measurements.

iPS-Cell Technology and the Problem of Genetic Instability—Can It Ever Be Safe for Clinical Use?

Publisher: MDPI AG

Date: 28-02-2019

DOI: 10.3390/JCM8030288

Abstract: The use of induced Pluripotent Stem Cells (iPSC) as a source of autologous tissues shows great promise in regenerative medicine. Nevertheless, several major challenges remain to be addressed before iPSC-derived cells can be used in therapy, and experience of their clinical use is extremely limited. In this review, the factors affecting the safe translation of iPSC to the clinic are considered, together with an account of efforts being made to overcome these issues. The review draws upon experiences with pluripotent stem-cell therapeutics, including clinical trials involving human embryonic stem cells and the widely transplanted mesenchymal stem cells. The discussion covers concerns relating to: (i) the reprogramming process (ii) the detection and removal of incompletely differentiated and pluripotent cells from the resulting medicinal products and (iii) genomic and epigenetic changes, and the evolutionary and selective processes occurring during culture expansion, associated with production of iPSC-therapeutics. In addition, (iv) methods for the practical culture-at-scale and standardization required for routine clinical use are considered. Finally, (v) the potential of iPSC in the treatment of human disease is evaluated in the light of what is known about the reprogramming process, the behavior of cells in culture, and the performance of iPSC in pre-clinical studies.

Swelling and collapse of an adsorbed pH-responsive film-forming microgel measured by optical reflectometry and QCM

Publisher: American Chemical Society (ACS)

Date: 26-08-2010

DOI: 10.1021/LA1023218

Abstract: The swelling and deswelling of a pH-responsive electrosterically stabilized poly[2-(diethylamino)ethyl methacrylate] microgel adsorbed to silica surfaces have been quantified using the techniques of optical reflectometry (OR) and quartz crystal microbalance (QCM). It is shown that by utilizing and comparing OR measurements performed on wafers with differing oxide layer thicknesses the adsorbed amount and film thickness of the adsorbed microgel in both the swollen and deswollen forms can be determined. Also, the kinetics of the transition can be followed, revealing that collapse is a slower process than swelling, and direct support is provided for the formation of a dense outer layer or skin during collapse that slows the deswelling process. It is shown that the adsorption of this low glass transition temperature film-forming microgel latex is robust to changes in pH after an initial swelling event which is responsible for desorption of a large and variable fraction of the initially adsorbed polymer. Subsequent deswelling and swelling of the adsorbed film indicates that adsorption to a surface greatly hinders the volumetric swelling capacity of the microgel film. In its swollen state the film is only 3-4 times thicker than the collapsed film, whereas for particles in bulk the volume increases by a factor of 20 upon protonation of the tertiary amine residues. QCM results show that even in the collapsed form the film contains a considerable amount of water. Further, the viscoelasticity of the deswollen film is similar to that of the swollen film, suggesting that the degree of cross-linking is the primary determinant of viscoelasticity.

Editorial overviewHot Topic - Nanobubbles and NanodropletsNanobubbles and Nanodroplets: from Basics to Applications

Publisher: Elsevier BV

Date: 10-2021

DOI: 10.1016/J.COCIS.2021.101516

Interaction of Particles with Surfactant Thin Films: Implications for Dust Suppression

Publisher: American Chemical Society (ACS)

Date: 22-05-2019

DOI: 10.1021/ACS.LANGMUIR.8B04230

Abstract: Understanding the interaction of particles with foams is important in antifoaming applications and dust suppression. In the former, the aim is for the particles to break the foam, whereas in the latter it is desirable that the stability of the foam is maintained or enhanced. The interaction of particles of different wettabilities with thin surfactant films is investigated with a Sheludko cell, enabling the thinning and rupture of the films to be studied in the presence and absence of a particle, using white-light interferometry. The films were prepared from the surfactant cetyltrimethylammonium bromide and a commercial dust suppression foaming agent. The film lifetimes are extended upon the addition of hydrophilic particles and reduced upon the addition of hydrophobic particles with advancing contact angles >90°. The Laplace pressure in the film surrounding a particle is calculated as a function of the contact angle and particle size, revealing that the meniscus surrounding hydrophilic particles has a positive Laplace pressure, which increases the lifetime of the film.

Specific-ion effects in non-aqueous systems

Publisher: Elsevier BV

Date: 06-2016

DOI: 10.1016/J.COCIS.2016.06.009

Roughness in Surface Force Measurements: Extension of DLVO Theory To Describe the Forces between Hafnia Surfaces

Publisher: American Chemical Society (ACS)

Date: 09-06-2017

DOI: 10.1021/ACS.JPCB.7B03131

Abstract: The interaction between colloidal particles is commonly viewed through the lens of DLVO theory, whereby the interaction is described as the sum of the electrostatic and dispersion forces. For similar materials acting across a medium at pH values remote from the isoelectric point the theory typically involves an electrostatic repulsion that is overcome by dispersion forces at very small separations. However, the dominance of the dispersion forces at short separations is generally not seen in force measurements, with the exception of the interaction between mica surfaces. The discrepancy for silica surfaces has been attributed to hydration forces, but this does not explain the situation for titania surfaces where the dispersion forces are very much larger. Here, the interaction forces between very smooth hafnia surfaces have been measured using the colloid probe technique and the forces evaluated within the DLVO framework, including both hydration forces and the influence of roughness. The measured forces across a wide range of pH at different salt concentrations are well described with a single parameter for the surface roughness. These findings show that even small degrees of surface roughness significantly alter the form of the interaction force and therefore indicate that surface roughness needs to be included in the evaluation of surface forces between all surfaces that are not ideally smooth.

Dynamically Gas‐Phase Switchable Super(de)wetting States by Reversible Amphiphilic Functionalization: A Powerful Approach for Smart Fluid Gating Membranes

Publisher: Wiley

Date: 16-11-2017

DOI: 10.1002/ADFM.201704423

Correction: What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9SC90050K

Abstract: Correction for ‘What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents’ by Virginia Mazzini et al. , Chem. Sci. , 2017, 8 , 7052–7065.

The influence of chain length and electrolyte on the adsorption kinetics of cationic surfactants at the silica–aqueous solution interface

Publisher: Elsevier BV

Date: 10-2003

DOI: 10.1016/S0021-9797(03)00631-3

Abstract: The equilibrium and kinetic aspects of the adsorption of alkyltrimethylammonium surfactants at the silica-aqueous solution interface have been investigated using optical reflectometry. The effect of added electrolyte, the length of the hydrocarbon chain, and of the counter- and co-ions has been elucidated. Increasing the length of the surfactant hydrocarbon chain results in the adsorption isotherm being displaced to lower concentrations. The adsorption kinetics indicate that above the cmc micelles are adsorbing directly to the surface and that as the chain length increases the hydrophobicity of the surfactant has a greater influence on the adsoption kinetics. While the addition of 10 mM KBr increases the CTAB maximal surface excess, there is no corresponding increase for the addition of 10 mM KCl to the CTAC system. This is attributed to the decreased binding efficiency of the chloride ion relative to the bromide ion. Variations in the co-ion species (Li, Na, K) have little effect on the adsorption rate and surface excess of CTAC up to a bulk electrolyte concentration of 10 mM. However, the rate of adsorption is increased in the presence of electrolyte. Slow secondary adsorption is seen over a range of concentrations for CTAC in the absence of electrolyte and importantly in the presence of LiCl the origin of this slow adsorption is attributed to a structural barrier to adsorption.

Reply to Comment on Water Droplet Motion Control on Superhydrophobic Surfaces: Exploiting the Wenzel-to-Cassie Transition

Publisher: American Chemical Society (ACS)

Date: 18-10-2011

DOI: 10.1021/LA203610V

A new DLVO-R theory

Publisher: Elsevier

Date: 2019

DOI: 10.1016/B978-0-12-813892-2.00005-7

Specific Ion Effects at the Vapor–Formamide Interface: A Reverse Hofmeister Series in Ion Concentration Depth Profiles

Publisher: American Chemical Society (ACS)

Date: 29-08-2023

DOI: 10.1021/ACS.LANGMUIR.3C01286

Floe strength characterization technique. An insight into silica aggregation

Publisher: American Chemical Society (ACS)

Date: 22-06-2004

DOI: 10.1021/LA049651P

Abstract: This paper tests an approach to the estimation of relative particle bond strength based on the nondimensional floc and aggregation factors. The strength of flocs formed by aggregating nanosized silica particles with the addition of potassium chloride (KCl) or cationic surfactants, alkyltrimethylammonium bromide (mixture of CTAB, DTAB, and MTAB) was analyzed. The bonding force of the flocs formed in surfactant compared to that formed in the KCl system was estimated using the new dimensional analysis approach. This force ratio was then compared to that obtained by atomic force microscopy.

Measurement of the adhesion of a viscoelastic sphere to a flat non-compliant substrate

Publisher: Informa UK Limited

Date: 12-2000

DOI: 10.1080/00218460008034527

Ion-specific coalescence of bubbles in mixed electrolyte solutions

Publisher: American Chemical Society (ACS)

Date: 14-12-2007

DOI: 10.1021/JP066400B

Direct Measurement of Interaction Forces between Surfaces in Liquids Using Atomic Force Microscopy

Publisher: Hosokawa Powder Technology Foundation

Date: 10-01-2019

DOI: 10.14356/KONA.2019013

Sensitivity of gravitational wave searches to the full signal of intermediate-mass black hole binaries during the first observing run of Advanced LIGO

Publisher: American Physical Society (APS)

Date: 11-01-2018

DOI: 10.1103/PHYSREVD.97.024016

Formation of Micronuclei Responsible for Decompression Sickness

Publisher: Elsevier BV

Date: 10-1996

DOI: 10.1006/JCIS.1996.0541

Evidence of shear-dependent boundary slip in newtonian liquids

Publisher: Springer Science and Business Media LLC

Date: 11-2003

DOI: 10.1140/EPJED/E2003-01-018-0

Abstract: The flow of Newtonian fluids was studied by directly measuring the hydrodynamic drainage force acting on a sphere approaching a flat surface. Our force measurements provide clear evidence of boundary slip and show that the degree of boundary slip is a function of the liquid viscosity and the shear rate. A shear-dependent boundary slippage was also observed in experiments with a polymer (PDMS). The liquids wetted the bounding surfaces either partially or completely. Our results have important consequences for the design of microfluidic devices, and in technological processes, such as lubrication and permeability of microporous media.

Forces between zinc sulphide surfaces; amplification of the hydrophobic attraction by surface charge

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9CP02797A

Abstract: Surface force measurements reveal that a small increase in surface charge enhance the long range hydrophobic attraction.

Differentiating between Nanoparticles and Nanobubbles by Evaluation of the Compressibility and Density of Nanoparticles

Publisher: American Chemical Society (ACS)

Date: 30-08-2018

DOI: 10.1021/ACS.JPCC.8B07174

GW190521: Orbital Eccentricity and Signatures of Dynamical Formation in a Binary Black Hole Merger Signal

Publisher: American Astronomical Society

Date: 23-10-2020

DOI: 10.3847/2041-8213/ABBE26

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

Publisher: Springer Science and Business Media LLC

Date: 26-04-2018

DOI: 10.1007/S41114-018-0012-9

Abstract: We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and $$90\\%$$ 90 % credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5– $$20~\\mathrm {deg}^2$$ 20 deg 2 requires at least three detectors of sensitivity within a factor of $$\\sim 2$$ ∼ 2 of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Application of a dynamic atomic force microscope for the measurement of lubrication forces and hydrodynamic thickness between surfaces bearing adsorbed polyelectrolyte layers

Publisher: American Chemical Society (ACS)

Date: 27-03-2003

DOI: 10.1021/MA025761W

Direct Measurement of Hydrophobic Forces:  A Study of Dissolved Gas, Approach Rate, and Neutron Irradiation

Publisher: American Chemical Society (ACS)

Date: 29-01-1999

DOI: 10.1021/LA9805793

Colloid probe characterization: Radius and roughness determination

Publisher: American Chemical Society (ACS)

Date: 28-02-2001

DOI: 10.1021/LA001506Y

A Deliberation on Nanobubbles at Surfaces and in Bulk

Publisher: Wiley

Date: 29-02-2012

DOI: 10.1002/CPHC.201100900

Abstract: Surface and bulk nanobubbles are two types of nanoscopic gaseous domain that have recently been discovered in interfacial physics. Both are expected to be unstable to dissolution because of the high internal pressure driving diffusion and the surface tension which squeezes the gas out, but there is a rapidly growing body of experimental evidence that demonstrates both bubble types to be stable. However, the two types of bubbles also differ in many respects: surface nanobubble stability is most probably assisted by the nearby wall, which can repel the water (in the case of hydrophobicity), accept physisorbed gas molecules, and reduce the surface area through which outfluxing can occur bulk nanobubbles, on the other hand, must stabilise themselves. This is perhaps through ionic shielding, perhaps through diffusive shielding, or perhaps through both. Herein, the features of both bubble types are described in idually, their common and disparate features are discussed, and emerging applications are examined.

Ion specificity in the measured concentration depth profile of ions at the Vapor-Glycerol interface

Publisher: Elsevier BV

Date: 11-2022

DOI: 10.1016/J.JCIS.2022.06.104

Abstract: Specific ion effects are manifest universally across many systems and solvents. Whilst broad understanding of these effects is emerging particularly for bulk effects, the perturbation introduced by the interfaces are generally not understood. We hypothesise that through a careful investigation of the distribution of ions at the glycerol-vapor interface we can better understand specific ion effects in this system and at interfaces. Neutral impact collision ion scattering spectroscopy (NICISS) is used to obtain and compare in idual ion concentration depth profiles (CDP) for a range of monovalent inorganic anions and cations at 12 glycerol electrolyte solutions surfaces. The distribution of ions at the vapor - glycerol interface is non-monotonic. Broadly, anions are concentrated at the outermost region of the interface and cations are depleted from the interface. The distribution of Cl

Adsorption Isotherms and Structure of Cationic Surfactants Adsorbed on Mineral Oxide Surfaces Prepared by Atomic Layer Deposition

Publisher: American Chemical Society (ACS)

Date: 21-11-2013

DOI: 10.1021/LA403439R

Abstract: The adsorption isotherms and aggregate structures of adsorbed surfactants on smooth thin-film surfaces of mineral oxides have been studied by optical reflectometry and atomic force microscopy (AFM). Films of the mineral oxides of titania, alumina, hafnia, and zirconia were produced by atomic layer deposition (ALD) with low roughness. We find that the surface strongly influences the admicelle organization on the surface. At high concentrations (2 × cmc) of cetyltrimethylammonium bromide (CTAB), the surfactant aggregates on a titania surface exhibit a flattened admicelle structure with an average repeat distance of 8.0 ± 1.0 nm whereas aggregates on alumina substrates exhibit a larger admicelle with an average separation distance of 10.5 ± 1.0 nm. A wormlike admicelle structure with an average separation distance of 7.0 ± 1.0 nm can be observed on zirconia substrates whereas a bilayered aggregate structure on hafnia substrates was observed. The change in the surface aggregate structure can be related to an increase in the critical packing parameter through a reduction in the effective headgroup area of the surfactant. The templating strength of the surfaces are found to be hafnia > alumina > zirconia > titania. Weakly templating surfaces are expected to have superior biocompatibility.

Avoiding bends

Publisher: Springer Science and Business Media LLC

Date: 04-1994

DOI: 10.1038/368490D0

Model Surfaces Produced by Atomic Layer Deposition

Publisher: The Chemical Society of Japan

Date: 05-10-2012

DOI: 10.1246/CL.2012.1247

Polyelectrolyte multilayers under compression: concurrent osmotic stress and colloidal probe atomic force microscopy

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C7SM02177A

Abstract: Colloidal interactions have been characterised using both osmotic stress and surface forces.

Surface forces in particle technology: Wet systems

Publisher: Elsevier BV

Date: 2015

DOI: 10.1016/J.PROENG.2015.01.103

Targeted numerical simulations of binary black holes for GW170104

Publisher: American Physical Society (APS)

Date: 23-03-2018

DOI: 10.1103/PHYSREVD.97.064027

Does gas supersaturation by a chemical reaction produce bulk nanobubbles?

Publisher: Elsevier BV

Date: 10-2019

DOI: 10.1016/J.JCIS.2019.07.016

Abstract: Supersaturation of dissolved gas is the most commonly reported method for generating long-lived bulk nanobubbles. However, these reports are treated with skepticism because of the lack of techniques that directly show that these particles are gas filled bubbles. Therefore, this work has tested the hypothesis that supersaturation obtained by a chemical reaction produces long-lived nanosized bubbles in bulk using an established protocol that relies on evaluating the density of nanoparticles and measuring their response to external pressure. Nanoparticles were generated using a chemical reaction between aqueous solutions of ammonium chloride and sodium nitrite. Standard nanoparticle sizing techniques, such as nanoparticle tracking analysis and dynamic light scattering, were utilized to determine the size and stability of the nanoparticles. Resonant mass measurement was used to measure the buoyant mass of the nanoparticles, and their compressibility was investigated by measuring their size under the application of external pressure. The formation of nanoparticles was consistent with the kinetics of nitrogen gas evolution produced in the reaction, where the nanoparticle size was shown to be dependent on the pH and concentration of the reactants. However, the chemical reaction was found to generate incompressible nanoparticles with a density larger than that of the solvent, confirming that these particles were not gas-filled bubbles.

Understanding specific ion effects and the Hofmeister series

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D2CP00847E

Abstract: This perspective reviews the historical explanations for specific ion effects, and explores the frontiers of the field before summarising its challenges and opportunities.

Water Droplet Motion Control on Superhydrophobic Surfaces: Exploiting the Wenzel-to-Cassie Transition

Publisher: American Chemical Society (ACS)

Date: 15-02-2011

DOI: 10.1021/LA104669K

Abstract: Water droplets on rough hydrophobic surfaces are known to exist in two states one in which the droplet is impaled on the surface asperities (Wenzel state) and the other, a superhydrophobic state in which air remains trapped beneath the droplet (Cassie state). Here, we demonstrate that water droplets can transit from the Wenzel-to-Cassie state even though the former is energetically favored. We find that two distinct superhydrophobic states are produced. One is a true Cassie state, whereas the other exhibits superhydrophobicity in the absence of a vapor phase being trapped in the surface roughness. Furthermore, we can selectively drive the motion of water droplets on tilted structured hydrophobic surfaces by exploiting Wenzel-to-Cassie transitions. This can be achieved by heating the substrate or by directly heating the droplet using a laser.

Coadsorption of Low-Molecular Weight Aromatic and Aliphatic Alcohols and Acids with the Cationic Surfactant, CTAB, on Silica Surfaces

Publisher: American Chemical Society (ACS)

Date: 03-06-0005

DOI: 10.1021/LA501197M

Abstract: We have investigated the coadsorption of a range of small molecules with the cationic surfactant CTAB to silica surfaces over a range of concentrations and CTAB to solute ratios and compared the coadsorption with adsorption in the presence of the salicylate ion. We find that molecules with aromatic character and molecules with double bonds are most favorably adsorbed, and we attribute this to cation-π bonding between the surfactant headgroups and the π orbitals of the unsaturated bonds of the solute molecules. The adsorption is complex and depends on chemical interactions between the solute molecules and the surfactant, which are highly specific to the structure of the solute. To improve our understanding of the specifics of these interactions, we have performed one-dimensional rotating frame Overhauser spectroscopy (ROESY) nuclear magnetic resonance experiments. These experiments show the complexity of the intermolecular interactions and can be used to determine the position of the solute molecule with regard to the CTAB molecules in the adsorbed aggregates. The ROESY spectrum for the salicylate anion is distinct from those of the other solute molecules and suggests that the anions are dimerizing. Along with the cation-π bonding between the dimers, this provides a model for the strong influence that salicylate has on adsorption, micellar structure, and viscoelasticity. The ROESY data indicate that the catechol molecule interacts with all parts of the surfactant alkane chains such that they wrap around the molecule, but this has little effect on the interfacial curvature or aggregate shape. More intense isophthalic acid-CTAB intermolecular ROEs compared to those of other aromatic solutes are consistent with an interaction between isophthalic acid and the headgroups of two surfactant molecules that slows the intramicellar motion of isophthalic acid. Differences in interactions between solute molecules and the aliphatic surfactant chains do not result in changes in micelle structure.

Shear-Dependent Boundary Slip in an Aqueous Newtonian Liquid

Publisher: American Physical Society (APS)

Date: 17-07-2001

DOI: 10.1103/PHYSREVLETT.87.054504

Sensing cantilever beam bending by the optical lever technique and its application to surface stress

Publisher: American Chemical Society (ACS)

Date: 14-02-2006

DOI: 10.1021/JP0536807

Abstract: Cantilever beams, both microscopic and macroscopic, are used as sensors in a great variety of applications. An optical lever system is commonly employed to determine the deflection and thereby the profile of the cantilever under load. The sensitivity of the optical lever must be calibrated, and this is usually achieved by application of a known load or deflection to the free end of the cantilever. When the sensing operation involves a different type of load or a combination of types of loadings, the calibration and the deflection values derived from it become invalid. Here we develop a master equation that permits the true deflection of the cantilever to be obtained simply from the measurement of the apparent deflection for uniformly distributed loadings and end-moment loadings. These loadings are relevant to the uniform adsorption or application of material to the cantilever or the application of a surface stress to the cantilever and should assist experimentalists using the optical lever, such as in the atomic force microscope, to measure cantilever deflections in a great variety of sensing applications. We then apply this treatment to the experimental evaluation of surface stress. Three forms of Stoney's equation that relate the apparent deflection to the surface stress, which is valid for both macroscopic and microscopic experiments, are derived. Analysis of the errors arising from incorrect modeling of the loading conditions of the cantilever currently applied in experiments is also presented. It is shown that the reported literature values for surface stress in microscopic experiments are typically 9% smaller than their true value. For macroscopic experiments, we demonstrate that the added mass of the film or coating generally dominates the measured deflection and must be accounted for accurately if surface stress measurements are to be made. Further, the reported measurements generally use a form of Stoney's equation that is in error, resulting in an overestimation of surface stress by a factor >5.

Interfacial Nanobubbles Are Leaky: Permeability of the Gas/Water Interface

Publisher: American Chemical Society (ACS)

Date: 02-06-2014

DOI: 10.1021/NN5016049

Abstract: Currently there is no widespread agreement on an explanation for the stability of surface nanobubbles. One means by which several explanations can be differentiated is through the predictions they make about the degree of permeability of the gas-solution interface. Here we test the hypothesis that the gas-solution interface of surface nanobubbles is permeable by experimental measurements of the exchange of carbon dioxide. We present measurements by attenuated total reflection Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM), demonstrating that the gas inside surface nanobubbles is not sealed inside the bubbles, but rather exchanges with the dissolved gas in the liquid phase. Such gas transfer is measurable by using the infrared active gas CO2. We find that bubbles formed in air-saturated water that is then perfused with CO2-saturated water give rise to distinctive gaseous CO2 signals in ATR-FTIR measurements. Also the CO2 gas inside nanobubbles quickly dissolves into the surrounding air-saturated water. AFM images before and after fluid exchange show that CO2 bubbles shrink upon exposure to air-equilibrated liquid but remain stable for hours. Also air bubbles in contact with CO2-saturated water increase in size and Ostwald ripening occurs more rapidly due to the relatively high gas solubility of CO2 in water.

Use of the light-lever technique for the measurement of colloidal forces

Publisher: Elsevier BV

Date: 12-1998

DOI: 10.1016/S0927-7757(98)00274-X

Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive

Publisher: American Association for the Advancement of Science (AAAS)

Date: 05-08-2016

DOI: 10.1126/SCIADV.1600579

Abstract: The pH response of strong polyelectrolyte brushes originates from the pH-mediated reorganization of hydrogen bond network.

Porous carbon nanotube/polyvinylidene fluoride composite material: Superhydrophobicity/superoleophilicity and tunability of electrical conductivity

Publisher: Elsevier BV

Date: 10-2014

DOI: 10.1016/J.POLYMER.2014.08.062

Surface force measurements between Titanium Dioxide surfaces prepared by Atomic Layer Deposition in electrolyte solutions reveal Non-DLVO interactions: Influence of water and argon plasma cleaning

Publisher: American Chemical Society (ACS)

Date: 18-02-2014

DOI: 10.1021/LA5000205

Abstract: Surface force measurements between titania surfaces in electrolyte solutions have previously revealed an unexplained long-range repulsive force at high pH, not described by Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. Here, the surface forces between titania surfaces produced by atomic layer deposition (ALD) and cleaned using a variety of methods have been measured to determine the influence of the cleaning protocol on the measured forces and test the hypothesis that water plasma cleaning of the surface results in non-DLVO forces at high pH. For argon plasma and water plasma cleaned surfaces, a diffuse double layer repulsion and van der Waals attraction is observed near the isoelectric point. At high pH, the force remained repulsive up until contact, and no van der Waals attraction or adhesion was observed. Differences in the measured forces are explained by modification of the surface chemistry during cleaning, which alters the density of charged groups on the surface, but this cannot explain the observed disagreement with DLVO theory at high pH.

Probing the Hofmeister series beyond water: Specific-ion effects in non-aqueous solvents

Publisher: AIP Publishing

Date: 14-02-2018

DOI: 10.1063/1.5017278

Abstract: We present an experimental investigation of specific-ion effects in non-aqueous solvents, with the aim of elucidating the role of the solvent in perturbing the fundamental ion-specific trend. The focus is on the anions: CH3COO−& F−& Cl−& Br−& I−& ClO4−& SCN− in the solvents water, methanol, formamide, dimethyl sulfoxide (DMSO), and propylene carbonate (PC). Two types of experiments are presented. The first experiment employs the technique of size exclusion chromatography to evaluate the elution times of electrolytes in the different solvents. We observe that the fundamental (Hofmeister) series is observed in water and methanol, whilst the series is reversed in DMSO and PC. No clear series is observed for formamide. The second experiment uses the quartz crystal microbalance technique to follow the ion-induced swelling and collapse of a polyelectrolyte brush. Here the fundamental series is observed in the protic solvents water, methanol, and formamide, and the series is once again reversed in DMSO and PC. These behaviours are not attributed to the protic/aprotic nature of the solvents, but rather to the polarisability of the solvents and are due to the competition between the interaction of ions with the solvent and the surface. A rule of thumb is proposed for ion specificity in non-aqueous solvents. In weakly polarisable solvents, the trends in specific-ion effects will follow those in water, whereas in strongly polarisable solvents the reverse trend will be observed. Solvents of intermediate polarisability will give weak specific-ion effects.

Focused ion beam milling as a universal template technique for patterned growth of carbon nanotubes

Publisher: AIP Publishing

Date: 26-02-1818

DOI: 10.1063/1.2710785

Abstract: Focused ion beam (FIB) milling system has been used to create nanosized patterns as the template for patterned growth of carbon nanotubes on Si substrate surface without predeposition of metal catalysts. Carbon nanotubes only nucleate and grow on the template under controlled pyrolysis of iron phthalocyanine at 1000°C. The size, growth direction, and density of the patterned nanotubes can be controlled under different growth conditions and template sizes. Atomic force microscopy and electron microscopy analyses reveal that the selective growth on the FIB template is due to its special surface morphology and crystalline structure.

Adsorption of 12-s-12 Gemini Surfactants at the Silica−Aqueous Solution Interface

Publisher: American Chemical Society (ACS)

Date: 07-03-2003

DOI: 10.1021/JP026626O

Interfacial and Bulk Nanostructure of Liquid Polymer Nanocomposites

Publisher: American Chemical Society (ACS)

Date: 18-03-2015

DOI: 10.1021/ACS.LANGMUIR.5B00255

Abstract: Liquid polymer nanocomposites (l-PNCs) have been prepared using silica nanoparticles with diameters of 15 nm (l-PNC-15) and 24 nm (l-PNC-24), and Jeffamine M-2070, an amine-terminated ethylene oxide ropylene oxide (PEO/PPO, ratio 31/10) copolymer. Jeffamine M-2070 was used as the host liquid in which the particles were suspended and was also grafted onto the particle surface to prevent aggregation. The grafting density of Jeffamine M-2070 on the particle surfaces was ∼0.75 chains nm(-2). When the total polymer content (surface layer + host) was greater than ∼30 wt %, the PNC was a liquid, while at lower polymer volume fractions the PNC was solid. In this work, the bulk and surface structures of l-PNCs with ∼70 wt % polymer and 30% silica are characterized and compared. Small-angle neutron scattering (SANS) was used to probe the bulk structure of the l-PNCs and revealed that the particles are well-dispersed with minor clustering in l-PNC-15 and substantial clustering in l-PNC-24. This is attributed to stronger van der Waals attractions between particles due to the larger particle size in l-PNC-24. Corresponding effects were revealed using tapping mode atomic force microscopy (TM-AFM) at the l-PNC-air interface clustering was minimal on the surface of l-PNC-15 but significant for l-PNC-24 droplets. In regions of the l-PNC where the particles were well-dispersed, the spacing between particles is consistent with their volume fractions. This is the first time that the distribution of polymer and particles within l-PNCs has been imaged in situ.

Application of the Light-Lever Technique to the Study of Colloidal Forces

Publisher: American Chemical Society (ACS)

Date: 1996

DOI: 10.1021/LA951518X

Mechanism of cationic surfactant adsorption at the solid–aqueous interface

Publisher: Elsevier BV

Date: 05-2003

DOI: 10.1016/S0001-8686(03)00002-2

Ion-beam-induced porosity of GaN

Publisher: AIP Publishing

Date: 04-09-2000

DOI: 10.1063/1.1290722

Abstract: Wurtzite GaN films bombarded with heavy ions (197Au+) show anomalous swelling of the implanted region with corresponding volume expansion up to ∼50%. Results show that this phenomenon is due to the formation of a porous layer of amorphous GaN. An important implication of this study for the fabrication of GaN-based devices is that amorphization of GaN should be avoided during ion implantation.

Adsorption Kinetics and Structural Arrangements of Cetylpyridinium Bromide at the Silica−Aqueous Interface

Publisher: American Chemical Society (ACS)

Date: 07-09-2001

DOI: 10.1021/LA001396V

Laser actuation of cantilevers for picometre amplitude dynamic force microscopy

Publisher: Springer Science and Business Media LLC

Date: 04-07-2014

DOI: 10.1038/SREP05567

Abstract: As nanoscale and molecular devices become reality, the ability to probe materials on these scales is increasing in importance. To address this, we have developed a dynamic force microscopy technique where the flexure of the microcantilever is excited using an intensity modulated laser beam to achieve modulation on the picoscale. The flexure arises from thermally induced bending through differential expansion and the conservation of momentum when the photons are reflected and absorbed by the cantilever. In this study, we investigated the photothermal and photon pressure responses of monolithic and layered cantilevers using a modulated laser in air and immersed in water. The developed photon actuation technique is applied to the stretching of single polymer chains.

The electrostatic origins of specific ion effects: quantifying the Hofmeister series for anions

Publisher: Royal Society of Chemistry (RSC)

Date: 2021

DOI: 10.1039/D1SC03568A

Abstract: Analysis of ions’ radial charge densities reveals they correlate with many specific ion effects, and provides a new basis to explain and quantify the 130-year-old Hofmeister series for anions.

Ion-Specific Influence of Electrolytes on Bubble Coalescence in Nonaqueous Solvents

Publisher: American Chemical Society (ACS)

Date: 04-07-2008

DOI: 10.1021/LA8008738

Abstract: We report the effects of electrolytes on bubble coalescence in nonaqueous solvents methanol, formamide, propylene carbonate, and dimethylsulfoxide (DMSO). Results in these solvents are compared to the ion-specific bubble coalescence inhibition observed in aqueous electrolyte solutions, which is predicted by simple, empirical ion combining rules. Coalescence inhibition by electrolytes is observed in all solvents, at a lower concentration range (0.01 M to 0.1M) to that observed in water. Formamide shows ion-specific salt effects dependent upon ion combinations in a way analogous to the combining rules observed in water. Bubble coalescence in propylene carbonate is also consistent with ion-combining rules, but the ion assignments differ to those for water. In both methanol and DMSO all salts used are found to inhibit bubble coalescence. Our results show that electrolytes influence bubble coalescence in a rich and complex way, but with notable similarities across all solvents tested. Coalescence is influenced by the drainage of fluid between two bubbles to form a film and then the rupture of the film and one might expect that these processes will vary dramatically between solvents. The similarities in behavior we observe show that coalescence inhibition is unlikely to be related to the surface forces present but is perhaps related to the dynamic thinning and rupture of the liquid film through the hydrodynamic boundary condition.

Cleaning with Bulk Nanobubbles

Publisher: American Chemical Society (ACS)

Date: 29-04-2016

DOI: 10.1021/ACS.LANGMUIR.6B01004

Abstract: The electrolysis of aqueous solutions produces solutions that are supersaturated in oxygen and hydrogen gas. This results in the formation of gas bubbles, including nanobubbles ∼100 nm in size that are stable for ∼24 h. These aqueous solutions containing bubbles have been evaluated for cleaning efficacy in the removal of model contaminants bovine serum albumin and lysozyme from surfaces and in the prevention of the fouling of surfaces by these same proteins. Hydrophilic and hydrophobic surfaces were investigated. It is shown that nanobubbles can prevent the fouling of surfaces and that they can also clean already fouled surfaces. It is also argued that in practical applications where cleaning is carried out rapidly using a high degree of mechanical agitation the role of cleaning agents is not primarily in assisting the removal of soil but in suspending the soil that is removed by mechanical action and preventing it from redepositing onto surfaces. This may also be the primary mode of action of nanobubbles during cleaning.

Dynamics of supercooled water in mesoporous silica matrix MCM-48-S

Publisher: Springer Science and Business Media LLC

Date: 11-2003

DOI: 10.1140/EPJED/E2003-01-015-3

Abstract: Using three different quasielastic neutron spectrometers with widely different resolutions, we have been able to study the microscopic translational and rotational dynamics of water, in a mesoporous silica matrix MCM-48-S, from T=300 K to 220 K, with a single consistent model. We formulated our fitting routine using the relaxing cage model. Thus, from the fit of the experimental data, we extracted the fraction of water bound to the surface of the pore, the characteristic relaxation times of the long-time translational and rotational decays, the stretch exponent describing the shape of the relaxation processes, and the power exponent determining the Q-dependence of the translational relaxation time. A tremendous slowing down of the rotational relaxation time, as compared to the translational one, has been observed.

Impact of the wavelike nature of Proca stars on their gravitational-wave emission

Publisher: American Physical Society (APS)

Date: 06-12-2022

DOI: 10.1103/PHYSREVD.106.124011

Wetting of nanophases: Nanobubbles, nanodroplets and micropancakes on hydrophobic surfaces

Publisher: Elsevier BV

Date: 08-2015

DOI: 10.1016/J.CIS.2014.07.008

Abstract: The observation by Atomic Force Microscopy of a range of nanophases on hydrophobic surfaces poses some challenging questions, not only related to the stability of these objects but also regarding their wetting properties. Spherical capped nanobubbles are observed to exhibit contact angles that far exceed the macroscopic contact angle measured for the same materials, whereas nanodroplets exhibit contact angles that are much the same as the macroscopic contact angle. Micropancakes are reported to consist of gas, in which case their wetting properties are mysterious. They should only be stable when the van der Waals forces act to thicken the film whereas for a gas, the van der Waals forces will always act to thin the film. Here we examine the available evidence and contribute some additional experiments in order to review our understanding of the wetting properties of these nanophases. We demonstrate that if in fact micropancakes consist of a contaminant their wetting properties can be explained, though the very high contact angles of nanobubbles remain unexplained.

The Role of Citric Acid in the Stabilization of Nanoparticles and Colloidal Particles in the Environment: Measurement of Surface Forces between Hafnium Oxide Surfaces in the Presence of Citric Acid

Publisher: American Chemical Society (ACS)

Date: 13-02-2018

DOI: 10.1021/ACS.LANGMUIR.7B03116

Abstract: The interactions between colloidal particles and nanoparticles determine solution stability and the structures formed when the particles are unstable to flocculation. Therefore, knowledge of the interparticle interactions is important for understanding the transport, dissolution, and fate of particles in the environment. The interactions between particles are governed by the surface properties of the particles, which are altered when species adsorb to the surface. The important interactions in the environment are almost never those between the bare particles but rather those between particles that have been modified by the adsorption of natural organic materials. Citric acid is important in this regard not only because it is present in soil but also as a model of humic and fulvic acids. Here we have studied the surface forces between the model metal oxide surface hafnia in the presence of citric acid in order to understand the stability of colloidal particles and nanoparticles. We find that citric acid stabilizes the particles over a wide range of pH at low to moderate ionic strength. At high ionic strength, colloidal particles will flocculate due to a secondary minimum, resulting in aggregates that are dense and easily redispersed. In contrast, nanoparticles stabilized by citric acid remain stable at high ionic strengths and therefore exist in solution as in idual particles this will contribute to their dispersion in the environment and the uptake of nanoparticles by mammalian cells.

Specific ion effects at the air–water interface: Experimental studies

Publisher: WORLD SCIENTIFIC

Date: 12-2009

DOI: 10.1142/9789814271585_0007

In situ calibration of colloid probe cantilevers in force microscopy: Hydrodynamic drag on a sphere approaching a wall

Publisher: American Chemical Society (ACS)

Date: 23-08-2001

DOI: 10.1021/LA010424M

Adsorption Pattern of Mixtures of Trimethylammonium-Modified Hydroxyethylcellulose and Sodium Dodecyl Sulfate at Solid−Liquid Interfaces

Publisher: American Chemical Society (ACS)

Date: 20-02-2004

DOI: 10.1021/LA035112T

Abstract: We studied mixtures of aqueous solutions of cationic hydroxyethylcellulose JR400 polymer and anionic sodium dodecyl sulfate using dynamic light scattering and atomic force microscopy (AFM). A ternary phase diagram was established showing three interesting realms of the polymer-surfactant-water mixture: a preprecipitation area of lowered viscosity (polymer excess) compared to the pure polymer solution, a postprecipitation area (resolubilization at surfactant excess), and highly diluted s les with a stoichiometrical surfactant-polymer ratio close to that of maximum precipitation. S les with various compositions representing these areas were imaged by atomic force microscopy on mica and on hydrophobically modified silica in contact mode. A correlation between light scattering data concerning particle size and, more important, structuring in the bulk on one hand and AFM images on the other hand was observed. It was revealed that the influence of surface properties is of less importance for adsorption, compared to the influence of the mixture in the bulk, provided that the mixture is prepared prior to adsorption.

Determination of coupled solvent mass in quartz crystal microbalance measurements using deuterated solvents

Publisher: Elsevier BV

Date: 06-2003

DOI: 10.1016/S0021-9797(03)00210-8

Effects of Electrolytes on Bubble Coalescence

Publisher: American Chemical Society (ACS)

Date: 08-1997

DOI: 10.1021/LA960034D

A gravitational-wave standard siren measurement of the Hubble constant

Publisher: Springer Science and Business Media LLC

Date: 16-10-2017

DOI: 10.1038/NATURE24471

Abstract: On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder': the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.

Colloidal Systems in Concentrated Electrolyte Solutions Exhibit Re-entrant Long-Range Electrostatic Interactions due to Underscreening

Publisher: American Chemical Society (ACS)

Date: 05-05-2022

DOI: 10.1021/ACS.LANGMUIR.2C00519

Hofmeister Effects in pH Measurements:  Role of Added Salt and Co-Ions

Publisher: American Chemical Society (ACS)

Date: 11-03-2003

DOI: 10.1021/JP026804D

Surface Forces between Titanium Dioxide Surfaces in the Presence of Cationic Surfactant as a Function of Surfactant Concentration, Electrolyte Concentration, and pH

Publisher: American Chemical Society (ACS)

Date: 03-03-2014

DOI: 10.1021/LA500298U

Abstract: Titanium dioxide (titania) surfaces produced by atomic layer deposition (ALD) are suitable for surfactant adsorption and surface force measurements. Adsorption isotherms for cetyltrimethylammonium bromide (CTAB) on ALD titanium dioxide surfaces were measured using optical reflectometry (OR), and surface force measurements between ALD titanium dioxide surfaces in aqueous CTAB solutions were measured using the colloid probe technique at different pH and electrolyte concentrations. Measurements were performed at a range of concentrations below and above the common intersection point (CIP) where adsorption is dominated by electrostatic and hydrophobic interactions, respectively. An examination of surfactant adsorption above and below the isoelectric point (IEP) was performed. Interestingly, significant levels of adsorption were observed below the IEP where the electrostatic interactions are unfavorable. The adsorption results are used to interpret the force data, which is dependent upon the amount of surfactant adsorbed and the electrolyte concentration and pH. The surface force data is compared to DLVO theory. Poor fits are obtained when Lifshitz theory is used to describe the dispersion forces. However, all of the data are fit well with a dispersion force of reduced magnitude. The kinetics of adsorption was measured and reveals very slow adsorption kinetics below the critical micelle concentration as a result of the monomer-by-monomer formation of aggregates on the surface.

Study of the Long-Range Hydrophobic Attraction in Concentrated Salt Solutions and Its Implications for Electrostatic Models

Publisher: American Chemical Society (ACS)

Date: 13-05-1998

DOI: 10.1021/LA970591F

GW190521 as a Merger of Proca Stars: A Potential New Vector Boson of 8.7×

Publisher: American Physical Society (APS)

Date: 24-02-2021

DOI: 10.1103/PHYSREVLETT.126.081101

Solving the Teukolsky equation with physics-informed neural networks

Publisher: American Physical Society (APS)

Date: 13-03-2023

DOI: 10.1103/PHYSREVD.107.064025

PEO-PPO-PEO surfactant exfoliated graphene cyclodextrin drug carriers for photoresponsive release

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.MATCHEMPHYS.2017.11.012

Atomic force microscopy study of the interaction between adsorbed poly(ethylene oxide) layers: Effects of surface modification and approach velocity

Publisher: American Chemical Society (ACS)

Date: 11-02-2005

DOI: 10.1021/LA047942S

Abstract: The interaction forces between layers of the triblock copolymer Pluronic F108 adsorbed onto hydrophobic radio frequency glow discharge (RFGD) thin film surfaces and hydrophilic silica, in polymer-free 0.15 M NaCl solution, have been measured using the atomic force microscope (AFM) colloid probe technique. Compression of Pluronic F108 layers adsorbed on the hydrophobic RFGD surfaces results in a purely repulsive force due to the steric overlap of the layers, the form of which suggests that the PEO chains adopt a brush conformation. Subsequent fitting of these data to the polymer brush models of Alexander-de Gennes and Milner, Witten, and Cates confirms that the adsorbed Pluronic F108 adsorbs onto hydrophobic surfaces as a polymer brush with a parabolic segment density profile. In comparison, the interaction between Pluronic F108 layers adsorbed on silica exhibits a long ranged shallow attractive force and a weaker steric repulsion. The attractive component is reasonably well described by van der Waals forces, but polymer bridging cannot be ruled out. The weaker steric component of the force suggests that the polymer is less densely packed on the surface and is less extended into solution, existing as polymeric isolated mushrooms. When the surfaces are driven together at high piezo r velocities, an additional repulsive force is measured, attributable to hydrodynamic drainage forces between the surfaces. In comparing theoretical predictions of the hydrodynamic force to the experimentally obtained data, agreement could only be obtained if the flow profile of the aqueous solution penetrated significantly into the polymer brush. This finding is in line with the theoretical predictions of Milner and provides further evidence that the segment density profile of the adsorbed polymer brush is parabolic. A velocity dependent additional stepped repulsive force, reminiscent of a solvation oscillatory force, is also observed when the adsorbed layers are compressed under high loads. This additional force is presumably a result of hindered drainage of water due to the presence of a high volume fraction of polymer chains between the surfaces.

The effect of electrolytes on bubble coalescence in water

Publisher: American Chemical Society (ACS)

Date: 09-1993

DOI: 10.1021/J100141A047

Inhibition of bubble coalescence by osmolytes: Sucrose, other sugars, and urea

Publisher: American Chemical Society (ACS)

Date: 02-07-2009

DOI: 10.1021/LA9015355

Abstract: We report on bubble coalescence inhibition by non-surface-active, nonelectrolytes urea and sucrose, and other small sugars, in aqueous solution. Urea has no effect on bubble stability up to high concentrations>1 M, while sucrose inhibits coalescence in the range 0.01-0.3 M, similar to inhibiting electrolytes. Urea and sucrose both increase bubble coalescence inhibition in inhibiting and noninhibiting electrolytes in a cooperative manner, but urea decreases the efficacy of sucrose in mixed solutions. Several mono- and disaccharides also inhibit bubble coalescence at approximately 0.1 M, and the sugars vary in effectiveness. Disaccharides are more effective than the sum of their in idual monosaccharide constituents, and sugars with very similar structures (for instance, diastereomers galactose and mannose) can show large differences in coalescence inhibition and hence thin film stability. We conclude that solute charge is not required for bubble coalescence inhibition, which indicates that the mechanism is not one of electrostatic surface repulsion and instead an effect on dynamic film thinning other than Gibbs-Marangoni elasticity is implicated. Solute structure is important in determining coalescence.

From Hofmeister to hydrotrope: Effect of anion hydrocarbon chain length on a polymer brush

Publisher: Elsevier BV

Date: 03-2023

DOI: 10.1016/J.JCIS.2022.12.114

The origin of surface stress induced by adsorption of iodine on gold

Publisher: American Chemical Society (ACS)

Date: 06-09-2006

DOI: 10.1021/JP063232E

Abstract: The cantilever technique for the measurement of film stress on both macroscopic and microscopic cantilevers is validated, then applied to the experimental determination of film stress induced by the adsorption of a monolayer of iodine onto a gold substrate. A model is proposed that relates the change in the interatom potential upon chemisorption of iodine onto gold to the measured film stress. Excellent agreement is found with the experimentally determined value. This result gives insight into the origins of film stress that is observed in all thin film and coating applications.

High Yield Stress Associated with Capillary Attraction between Alumina Surfaces in the Presence of Low Molecular Weight Dicarboxylic Acids

Publisher: American Chemical Society (ACS)

Date: 05-10-2010

DOI: 10.1021/LA902976N

Abstract: Adsorbed low molecular weight charged molecules are known to give rise to a range of surface forces that affect the rheological behavior of oxide dispersions. The behavior of dicarboxylic acid bolaform compounds in alumina slurry was investigated to determine the influence of the molecular structure on the nanoscale interactions between alumina surfaces and on the macroscopic properties of the slurry. The surface forces in dispersions and between a single particle and a flat surface were characterized by yield stress and atomic force microscopy (AFM) respectively. Absorbed muconic acid increased the yield stress of the alumina system, which indicates an additional attractive interaction between the particles. Adsorbed trans,trans (TT) muconic acid resulted in a much higher yield stress than cis,cis (CC) muconic acid. Force-distance data obtained via AFM displayed features indicating the presence of a capillary force attraction at low pH between the alumina surfaces when TT and CC muconic acids were adsorbed at high surface coverage. This force appeared to explain the high yield stress at low pH (pH 3.6), but the absence of a net attractive force at higher pH (pH 5) did not correlate with the yield stress results. At low pH, the muconic acids become less soluble in the confined space between the interacting surfaces resulting in the formation of an "oily" muconic acid phase located between the interacting surfaces. The nanosized "oil" phase is the source of the capillary force.

Underscreening in concentrated electrolytes: Re-entrant swelling in polyelectrolyte brushes

Publisher: Royal Society of Chemistry (RSC)

Date: 2023

DOI: 10.1039/D3CP02206D

Abstract: Hypersaline environments are ubiquitous in nature and are found in myriad technological processes. Recent empirical studies have revealed a significant discrepancy between the predicted and observed screening lengths at high...

Very small bubbles at surfaces—the nanobubble puzzle

Publisher: Royal Society of Chemistry (RSC)

Date: 2011

DOI: 10.1039/C0SM00558D

Cation-Specific Conformational Behavior of Polyelectrolyte Brushes: From Aqueous to Nonaqueous Solvent

Publisher: American Chemical Society (ACS)

Date: 23-10-2014

DOI: 10.1021/LA5033493

Abstract: We have investigated changes in the cation-specific conformational behavior of poly(sodium styrenesulfonate) (PSS) brushes as the solvent changes from water to methanol using a quartz crystal microbalance with dissipation (QCM-D). A solvation to desolvation transition of the grafted chains accompanied by swelling to the collapse transition of the brushes is observed for Na(+). In the case of Cs(+), the brushes undergo solvation to desolvation to resolvation accompanied by swelling to collapse to reswelling transitions. The resolvation and reswelling transitions for Cs(+) are induced by the charge inversion of the brushes via van der Waals interactions between Cs(+) and the brushes. All of the transitions for monovalent cations become less obvious as the methanol content increases. For alent Ca(2+) and trivalent La(3+), a solvation to desolvation to resolvation transition of the grafted chains accompanied by a swelling to collapse to reswelling transition of the brushes can be observed. The resolvation and reswelling of the brushes for the multivalent cations are induced by the charge inversion of the brushes via charge-image charge interactions. The extent of the transitions for the PSS brushes in the presence of multivalent cations is only slightly influenced by the methanol content.

Surface Roughness and Hydrodynamic Boundary Slip of a Newtonian Fluid in a Completely Wetting System

Publisher: American Physical Society (APS)

Date: 08-04-2003

DOI: 10.1103/PHYSREVLETT.90.144501

Selective separation of oil and water with mesh membranes by capillarity

Publisher: Elsevier BV

Date: 09-2016

DOI: 10.1016/J.CIS.2016.05.008

Abstract: The separation of oil and water from wastewater generated in the oil-production industries, as well as in frequent oil spillage events, is important in mitigating severe environmental and ecological damage. Additionally, a wide arrange of industrial processes require oils or fats to be removed from aqueous systems. The immiscibility of oil and water allows for the wettability of solid surfaces to be engineered to achieve the separation of oil and water through capillarity. Mesh membranes with extreme, selective wettability can efficiently remove oil or water from oil/water mixtures through a simple filtration process using gravity. A wide range of different types of mesh membranes have been successfully rendered with extreme wettability and applied to oil/water separation in the laboratory. These mesh materials have typically shown good durability, stability as well as reusability, which makes them promising candidates for an ever widening range of practical applications.

Volcano Plots Emerge from a Sea of Nonaqueous Solvents: The Law of Matching Water Affinities Extends to All Solvents

Publisher: American Chemical Society (ACS)

Date: 25-07-2018

DOI: 10.1021/ACSCENTSCI.8B00348

Post-merger chirps from binary black holes as probes of the final black-hole horizon

Publisher: Springer Science and Business Media LLC

Date: 08-10-2020

DOI: 10.1038/S42005-020-00446-7

Abstract: The merger of a binary black hole gives birth to a highly distorted final black hole. The gravitational radiation emitted as this black hole relaxes presents us with the unique opportunity to probe extreme gravity and its connection with the dynamics of the black hole horizon. Using numerical relativity simulations, we demonstrate a connection between a concrete observable feature in the gravitational waves and geometrical features on the dynamical apparent horizon of the final black hole. Specifically, we show how the line-of-sight passage of a “cusp”-like defect on the horizon of the final black hole correlates with “chirp”-like frequency peaks in the post-merger gravitational-waves. These post-merger chirps should be observed and analyzed as the sensitivity of LIGO and Virgo increase and as future generation detectors, such as LISA and the Einstein Telescope, become operational.

Stiff chains inhibit and flexible chains promote protein adsorption to polyelectrolyte multilayers

Publisher: Royal Society of Chemistry (RSC)

Date: 2014

DOI: 10.1039/C4SM00413B

Abstract: The relative stiffness of polymers used to form polyelectrolyte multilayers can be used to control protein adsorption. Flexible chains promote protein adsorption whereas inflexible chains can produce antifouling surfaces, even if the constituent chains have no antifouling properties on their own.

Adsorption of Ionic Surfactants to a Plasma Polymer Substrate

Publisher: American Chemical Society (ACS)

Date: 09-04-2003

DOI: 10.1021/LA026852P

Adsorbed layer structure of a weak polyelectrolyte studied by colloidal probe microscopy and QCM-D as a function of pH and ionic strength

Publisher: Royal Society of Chemistry (RSC)

Date: 2004

DOI: 10.1039/B401376J

Corrigendum to “Specific-ion Effects in Non-Aqueous Systems” [Curr Opin Colloid Interface Sci 23 (June 2016) 82–93]

Publisher: Elsevier BV

Date: 10-2018

DOI: 10.1016/J.COCIS.2018.11.001

Walking lowers mortality risk in older US adults

Publisher: BMJ

Date: 05-05-2018

DOI: 10.1136/BMJEBM-2018-110902

Elasto-plastic and visco-elastic deformations of a polymer sphere measured using colloid probe and scanning electron microscopy

Publisher: Elsevier BV

Date: 2000

DOI: 10.1016/S0143-7496(00)00015-4

What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7SC02691A

Abstract: Consistent trends in ion-specificity across many solvents.

Re-entrant swelling and redissolution of polyelectrolytes arises from an increased electrostatic decay length at high salt concentrations

Publisher: Elsevier BV

Date: 11-2020

DOI: 10.1016/J.JCIS.2020.06.072

Implementing an Exercise Physiology Clinic for Consumers Within a Community Mental Health Service: A Real-World Evaluation

Publisher: Frontiers Media SA

Date: 24-11-2021

DOI: 10.3389/FPSYT.2021.791125

Abstract: Background: Physical activity significantly improves mental illness symptoms and physical health for people living with mental illness. Mental health services do not routinely provide their consumers with access to exercise professionals for physical activity engagement. Barriers exist to integrating physical activity as part of standard care including staff culture, finance, and resources. This study examines the feasibility of newly established exercise physiology clinic within a mental health service in Sydney, Australia. Methods: A single site, open trial was conducted in a community centre within a large mental health district. A meeting room was converted into a part-time exercise physiology clinic where in idualised physical activity interventions were delivered by an accredited exercise physiologist. Outcome measures including BMI, cardiovascular fitness, and self-reported physical activity were collected. Results: A total of 84 mental health consumers (17% of eligible consumers within the mental health service) participated in the clinic on average for one exercise session weekly. Moderate-to-vigorous physical activity significantly increased and sedentary time significantly decreased ( p & 0.001). Conclusions: Exercise physiology clinics are feasible within mental health services and should be incorporated as part of standard care.

Cleaning of Protein-Coated Surfaces Using Nanobubbles: An Investigation Using a Quartz Crystal Microbalance

Publisher: American Chemical Society (ACS)

Date: 08-10-2008

DOI: 10.1021/JP805143C

Effect of electrolytes on bubble coalescence

Publisher: Springer Science and Business Media LLC

Date: 07-1993

DOI: 10.1038/364317A0

Generation of nanoparticles upon mixing ethanol and water; Nanobubbles or Not?

Publisher: Elsevier BV

Date: 04-2019

DOI: 10.1016/J.JCIS.2019.01.134

Abstract: The debate as to whether nanoparticles that are formed upon mixing ethanol and water are nanobubbles or other nanoparticles has continued over the past decade. In this work, we test the hypothesis that long lived bulk nanobubbles are produced upon mixing ethanol and water, using techniques that probe the density and the pressure response of the nanoparticles. Nanoparticles were generated spontaneously upon mixing high-purity ethanol and high-purity water. The size distribution of these nanoparticles was obtained using nanoparticle tracking analysis. The mean density of the nanoparticles was determined using resonant mass measurement, and the response of the nanoparticles to the application of external pressure was measured using dynamic light scattering. The ethanol-water mixture was found to produce only positively buoyant particles, with a mean density of 0.91 ± 0.01 g/cm

Comment on “Deformation of fluid interfaces under double-layer forces stabilizes bubble dispersions”

Publisher: American Physical Society (APS)

Date: 06-1998

DOI: 10.1103/PHYSREVE.57.7362

Cleaning using nanobubbles: Defouling by electrochemical generation of bubbles

Publisher: Elsevier BV

Date: 12-2008

DOI: 10.1016/J.JCIS.2008.08.064

Abstract: Here we demonstrate that nanobubbles can be used as cleaning agents both for the prevention of surface fouling and for defouling surfaces. In particular nanobubbles can be used to remove proteins that are already adsorbed to a surface, as well as for the prevention of nonspecific adsorption of proteins. Nanobubbles were produced on highly oriented pyrolytic graphite (HOPG) surfaces electrochemically and observed by atomic force microscopy (AFM). Nanobubbles produced by electrochemical treatment for 20 s before exposure to bovine serum albumin (BSA) were found to decrease protein coverage by 26-34%. Further, pre-adsorbed protein on a HOPG surface was also removed by formation of electrochemically produced nanobubbles. In AFM images, the coverage of BSA was found to decrease from 100% to 82% after 50 s of electrochemical treatment. The defouling effect of nanobubbles was also investigated using radioactively labeled BSA. The amount of BSA remaining on a stainless steel surface decreased by approximately 20% following 3 min of electrochemical treatment and further cycles of treatment effectively removed more BSA from the surface. In situ observations indicate that the air-water interface of the nanobubble is responsible for the defouling action of nanobubbles.

Searching for the full symphony of black hole binary mergers

Publisher: American Physical Society (APS)

Date: 10-01-2018

DOI: 10.1103/PHYSREVD.97.023004

A scanning electron microscope study of the surface structure of mineral pigments, latices and thickeners used for paper coating on non-absorbent substrates

Publisher: Elsevier BV

Date: 05-2004

DOI: 10.1016/J.COLSURFA.2004.02.029

Reply to comment on 'the origin of surface stress induced by adsorption of iodine on gold'

Publisher: American Chemical Society (ACS)

Date: 12-05-2007

DOI: 10.1021/JP072844B

A review of parasitic zoonoses in a changing Southeast Asia

Publisher: Elsevier BV

Date: 11-2011

DOI: 10.1016/J.VETPAR.2011.07.013

Abstract: Parasitic zoonoses are common and widely distributed in the Southeast Asian region. However, the interactions between parasites, hosts and vectors are influenced by environmental, socio-cultural and livestock production changes that impact on the distribution, prevalence and severity of disease. In this review we provide an update on new knowledge in the context of ongoing changes for the food-borne pig associated zoonoses Taenia solium and Trichinella spp., the food-borne trematodes Opisthorchis viverrini and Clonorchis sinensis, the water-borne trematodes Schistosoma spp., the vector-borne zoonotic protozoa Plasmodium knowlesi and Leishmania spp. and the soil-borne zoonotic hookworm Ancylostoma ceylanicum. These various changes need to be considered when assessing or developing regional control programs or devising new research initiatives in a changing SE Asia.

Effect of electrolyte species on the adsorption of a cationic surfactant to silica: The common intersection point

Publisher: Elsevier BV

Date: 09-2009

DOI: 10.1016/J.COLSURFA.2009.01.014

Adsorption of dispersants at a polyester resin-alkane interface

Publisher: Elsevier BV

Date: 03-2011

DOI: 10.1016/J.COLSURFA.2011.01.022

Convolutional neural networks for the classification of glitches in gravitational-wave data streams

Publisher: IOP Publishing

Date: 04-09-2023

DOI: 10.1088/1361-6382/ACF26C

Abstract: We investigate the use of Convolutional Neural Networks (including the modern ConvNeXt network family) to classify transient noise signals (i.e. glitches) and gravitational waves in data from the Advanced LIGO detectors. First, we use models with a supervised learning approach, both trained from scratch using the Gravity Spy dataset and employing transfer learning by fine-tuning pre-trained models in this dataset. Second, we also explore a self-supervised approach, pre-training models with automatically generated pseudo-labels. Our findings are very close to existing results for the same dataset, reaching values for the F1 score of 97.18% (94.15%) for the best supervised (self-supervised) model. We further test the models using actual gravitational-wave signals from LIGO-Virgo’s O3 run. Although trained using data from previous runs (O1 and O2), the models show good performance, in particular when using transfer learning. We find that transfer learning improves the scores without the need for any training on real signals apart from the less than 50 chirp ex les from hardware injections present in the Gravity Spy dataset. This motivates the use of transfer learning not only for glitch classification but also for signal classification.

Modifiable cardiometabolic risk factors in youth with at-risk mental states: A cross-sectional pilot study

Publisher: Elsevier BV

Date: 11-2017

DOI: 10.1016/J.PSYCHRES.2017.08.034

Abstract: Young people experiencing psychotic illness engage in low amounts of physical activity have poor fitness levels and poor sleep quality. This study aimed to determine the prevalence of these modifiable cardiometabolic risk factors among in iduals with at-risk mental states (ARMS), who are at increased risk of developing psychosis. A cross-sectional study was conducted in a community-based youth mental health service. Thirty participants (23%♀, 21.3 ± 1.7 years old) were recruited, 10 with ARMS, 10 with first-episode psychosis (FEP) and 10 healthy volunteers. Physical activity levels were assessed using self-report and objective measures. Aerobic capacity, upper body strength, hamstring flexibility, forearm grip strength and core endurance were assessed. Sleep quality, depression and anxiety were measured by self-report questionnaire. The ARMS group did not differ significantly on anthropometric measures from FEP or healthy volunteers. They engaged in significantly less physical activity (p < 0.05) and had poorer sleep quality (p < 0.05) than healthy volunteers. Our results are consistent with other studies that found that youth with ARMS are at greater cardiometabolic risk. Interventions aimed at improving these modifiable risk factors may assist with preventing the decline in physical health associated with the development of psychiatric illness.

Mimicking enzymatic systems: modulation of the performance of polymeric organocatalysts by ion-specific effects

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C5CC09959E

Abstract: The performance of polymeric organocatalysts can be modulated by ion-specific effects based on the lessons learned from natural enzymatic systems.

An historical review of surface force measurement techniques

Publisher: Elsevier BV

Date: 11-1997

DOI: 10.1016/S0927-7757(97)00029-0

Numerical relativity injection analysis of signals from generically spinning intermediate mass black hole binaries in Advanced LIGO data

Publisher: American Physical Society (APS)

Date: 20-08-2020

DOI: 10.1103/PHYSREVD.102.044035

Experimental studies of the dynamic mechanical response of a single polymer chain

Publisher: American Chemical Society (ACS)

Date: 09-08-2006

DOI: 10.1021/MA060689D

Boundary slip in Newtonian liquids: a review of experimental studies

Publisher: IOP Publishing

Date: 10-10-2005

DOI: 10.1088/0034-4885/68/12/R05

Adsorption and Desorption of Polymer/Surfactant Mixtures at Solid−Liquid Interfaces:  Substitution Experiments

Publisher: American Chemical Society (ACS)

Date: 12-08-2004

DOI: 10.1021/LA0495581

Abstract: The adsorption of mixtures of aqueous solutions of cationic hydroxyethylcellulose polymer JR400 and anionic surfactant, sodium dodecyl sulfate, using atomic force microscopy (AFM) has been studied. S les with various compositions from different regions of the ternary phase diagram presented in our previous work were imaged by atomic force microscopy on freshly cleaved mica, and hydrophobically modified mica and silica in soft-contact mode. A series of "washing" (subsequent injection of compositions with gradually decreasing polymer/surfactant ratio) and "scratching" (mechanical agitation of the surface material with an AFM tip) experiments were performed. It was revealed that the morphology of the adsorbed layer altered in a manner following the changes in morphology in the bulk solution. These changes were evidenced in cluster formation in the layer. The results suggest that the influence of the surface was limited to the formation of the adsorbed layer where the local concentrations of polymer and surfactant were higher than those in the bulk. All further modifications were driven by changes in the mixture composition in bulk. Force measurements upon retraction reveal the formation of network structures within the surface aggregates that will greatly slow structural reequilibration.

Forward-Osmosis Desalination with Poly(Ionic Liquid) Hydrogels as Smart Draw Agents

Publisher: Wiley

Date: 23-03-2016

DOI: 10.1002/ADMA.201600205

Abstract: The combination of high desalination efficiency, negligible draw-solute leakage, nontoxicity, ease of regeneration, and effective separation to produce liquid water makes the smart draw agents developed here highly suited for forward-osmosis desalination.

Adsorption Kinetics and Structural Arrangements of Cationic Surfactants on Silica Surfaces

Publisher: American Chemical Society (ACS)

Date: 11-2000

DOI: 10.1021/LA0001272

The effect of electrolytes on bubble coalescence in water. [Erratum to document cited in CA119(18):189613s]

Publisher: American Chemical Society (ACS)

Date: 02-1994

DOI: 10.1021/J100056A025

Tracking Black Hole Kicks from Gravitational-Wave Observations

Publisher: American Physical Society (APS)

Date: 09-11-2018

DOI: 10.1103/PHYSREVLETT.121.191102

Flexible Transparent Hierarchical Nanomesh for Rose Petal-Like Droplet Manipulation and Lossless Transfer

Publisher: Wiley

Date: 23-04-2015

DOI: 10.1002/ADMI.201500071

2-year follow-up: Still keeping the body in mind.

Publisher: SAGE Publications

Date: 23-01-2018

DOI: 10.1177/0004867417753553

Armoured nanobubbles; ultrasound contrast agents under pressure

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1016/J.JCIS.2018.10.108

Abstract: Robust methods for differentiating long-lived nanobubbles from other nanoparticles are required. Evaluation of the density and compressibility of nanoparticles should enable nanobubbles to be differentiated from other nanoparticles, although the response of nanobubbles to pressure can be strongly influenced by a coating of insoluble surfactant. Here we evaluate the response of nanobubbles armoured with a coating of insoluble surfactants in order to determine if they can be differentiated from other nanoparticles. Dynamic light scattering was used to size candidate nanoparticles under the influence of external pressure and resonant mass measurements were employed to assess the density of candidate nanoparticles. The resonant mass measurement revealed a significant population of lipid-coated gas nanobubbles. These nanobubbles are proven to be gas entities, by their response to application of pressure. The pressure at which the gas within the nanobubbles condenses is shifted to higher pressure due to the mechanical resistance of the lipid shell, which shields the bubble contents from up to ∼0.8 atm. of the external pressure The presence of lipids of low solubility at the nanobubble-solution interface effectively results in a negative Laplace pressure, which stabilizes these nanobubbles against dissolution.

Insights into Ion Specificity in Water–Methanol Mixtures via the Reentrant Behavior of Polymer

Publisher: American Chemical Society (ACS)

Date: 09-01-2012

DOI: 10.1021/LA203979D

Abstract: In the present work, we have for the first time systematically investigated the ion specific reentrant behavior of poly(N-isopropylacryamide) (PNIPAM) in water-methanol mixtures. Turbidity measurements demonstrate that SCN(-) and ClO(4)(-) depress the reentrant transition, whereas other anions enhance the transition. As the anion changes from chaotropic to kosmotropic, the minimum critical phase transition temperature (T(min)) decreases and the corresponding volume fraction of methanol (X(M)) shifts to a larger value. Our results demonstrate that anion specificity is due to the anionic structure making/breaking effect on water/methanol complexes. Cations are found to have a lesser but still significant effect on the reentrant transition, and as T(min) decreases the corresponding X(M) also shifts to larger values as with the anions. Our studies show that cation specificity is induced by specific interactions between cations and PNIPAM chains. Furthermore, both anion and cation specificities are lified as X(M) is increased due to the formation of additional water/methanol complexes. Calorimetry measurements demonstrate that the ion specificity is dominated by changes in entropy.

Direct measurement of Van der Waals and diffuse double-layer forces between titanium dioxide surfaces produced by atomic layer deposition

Publisher: American Chemical Society (ACS)

Date: 27-03-2012

DOI: 10.1021/JP300533M

Mimosa Origami: A nanostructure-enabled directional self-organization regime of materials

Publisher: American Association for the Advancement of Science (AAAS)

Date: 03-06-2016

DOI: 10.1126/SCIADV.1600417

Abstract: Mimosa Origami: Large-scale dynamic self-assembly of soft materials powered by capillary-driven propagation of a pinpoint stimulus.

Ion specific electrolyte effects on thin film drainage in nonaqueous solvents propylene carbonate and formamide

Publisher: American Chemical Society (ACS)

Date: 09-06-2009

DOI: 10.1021/LA901099G

Calibration of colloid probe cantilevers using the dynamic viscous response of a confined liquid

Publisher: AIP Publishing

Date: 20-08-2003

DOI: 10.1063/1.1597950

Abstract: A method is described to determine the spring constant of colloid probe cantilevers used in force measurements with the atomic force microscope. An oscillatory drive applied to the substrate is coupled by viscous interactions to the colloid probe. The dynamic response of the probe, which is unaffected by static interactions, is then used to determine the spring constant of the cantilever. Thus an accurate calibration of the spring constant may be performed simultaneously with a normal colloidal probe force measurement in situ.

A Forecast of Developments in Scanned Probe Microscopy

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/CH06136

Abstract: From direct atom manipulation and nano-fabrication, to single molecule sensing and probing energy landscapes, the tools of the nanotech age are here. Scanned probe microscopies (SPM) offer opportunities to directly interact with matter in native environments and their evolution shows no signs of slowing. How might this toolkit adapt for new and outstanding problems in science? Here some directions are entertained and potential developments explored.

Physical Properties of Phase-Change Emulsions

Publisher: American Chemical Society (ACS)

Date: 13-10-2006

DOI: 10.1021/LA062097U

Abstract: Phase-change emulsions (PCE) are important in a variety of applications, from ultrasound imaging to the explosive material used in the mining industry, but until now there has been no adequate theory to describe their activation properties. The PCE consists of a low-boiling-point liquid, known as the volatile phase, dispersed in an aqueous phase. The volatile phase boils as a result of an increase in the temperature of the emulsion. The volume of the emulsion will increase during this phase transition, with the transition temperature and final volume of the emulsion highly dependent on the initial radius of the liquid droplets. Here a description of the change in boiling point and freezing point of the volatile phase, as well as the volume change of a droplet in the emulsion as a function of the initial droplet radius, is presented. The influence of volatile phase solubility, liquid-liquid interfacial tension, and final temperature are explored, accounting for the influence of confinement on the properties of the volatile phase. Beyond this, a means by which the diffusivity of the gas in the continuous liquid phase can be measured is derived.

Long-Term Stability of Surface Nanobubbles in Undersaturated Aqueous Solution.

Publisher: American Chemical Society (ACS)

Date: 18-12-2019

DOI: 10.1021/ACS.LANGMUIR.8B03487

Abstract: Surface nanobubbles should not be stable for more than a few milliseconds however they have been shown to persist for days. Pinning of the three-phase contact line of surface nanobubbles has been proposed to explain the discrepancy between the theoretical and experimental results. According to this model, two factors stabilize surface nanobubbles, namely solution oversaturation and surface pinning. Hereby, we investigate experimentally the impact of the solution saturation on the stability of nanobubbles. For this purpose, surface nanobubbles have been nucleated on hydrophobic surfaces by two methods, and then characterized by Atomic Force Microscopy (AFM). Thereafter, the surrounding liquid has been exchanged multiple times with partially degassed water. Two degassing techniques are presented. Both sets of experiments lead to the conclusion that surface nanobubbles are stable in undersaturated conditions for hours. We compare the measured lifetime of nanobubbles to calculations for pinned nanobubbles in undersaturated conditions. The stability of surface nanobubbles in undersaturated solutions observed here is incommensurate with the pinning mechanism as the origin of the long-term stability of surface nanobubbles.

Very slow surfactant adsorption at the solid-liquid interface is due to long lived surface aggregates

Publisher: Royal Society of Chemistry (RSC)

Date: 2009

DOI: 10.1039/B903768C

Structured near-infrared Magnetic Circular Dichroism spectra of the Mn4CaO5 cluster of PSII in T. vulcanus are dominated by Mn(IV) d-d ‘spin-flip’ transitions

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.BBABIO.2017.10.004

Abstract: Photosystem II passes through four metastable S-states in catalysing light-driven water oxidation. Variable temperature variable field (VTVH) Magnetic Circular Dichroism (MCD) spectra in PSII of Thermosynochococcus (T.) vulcanus for each S-state are reported. These spectra, along with assignments, provide a new window into the electronic and magnetic structure of Mn

Bubble coalescence and specific-ion effects

Publisher: Elsevier BV

Date: 08-2004

DOI: 10.1016/J.COCIS.2004.06.002

Potential observations of false deviations from general relativity in gravitational wave signals from binary black holes

Publisher: American Physical Society (APS)

Date: 09-07-2018

DOI: 10.1103/PHYSREVD.98.024019

Laboratorio De Economia E Modelagem Aplicada

Location: Brazil

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Australian National University

Location: Australia

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Discovery Projects - Grant ID: DP230102030

Start Date: 04-2023

End Date: 04-2026

Amount: $460,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0667994

Start Date: 2006

End Date: 12-2006

Amount: $1,000,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0774260

Start Date: 2007

End Date: 12-2009

Amount: $245,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0560758

Start Date: 2005

End Date: 12-2007

Amount: $187,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0883890

Start Date: 09-2009

End Date: 09-2012

Amount: $385,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP140100594

Start Date: 06-2015

End Date: 12-2018

Amount: $276,433.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP190100788

Start Date: 03-2019

End Date: 12-2022

Amount: $533,038.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP110101936

Start Date: 2011

End Date: 12-2014

Amount: $365,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0209181

Start Date: 02-2002

End Date: 12-2007

Amount: $573,782.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP140102371

Start Date: 2014

End Date: 12-2017

Amount: $565,000.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT0991933

Start Date: 11-2009

End Date: 12-2014

Amount: $788,800.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE140100090

Start Date: 04-2014

End Date: 12-2016

Amount: $200,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0882816

Start Date: 08-2008

End Date: 05-2009

Amount: $500,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0343788

Start Date: 10-2003

End Date: 12-2007

Amount: $291,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0237527

Start Date: 2001

End Date: 12-2002

Amount: $170,000.00

Funder: Australian Research Council