ORCID Profile
0000-0001-6093-5324
Current Organisation
University of Alberta
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Colloid and Surface Chemistry | Physical Chemistry (Incl. Structural) | Colloid and surface chemistry | Colloid And Surface Chemistry | Fluidisation and Fluid Mechanics | Interdisciplinary Engineering | Nanomaterials | Physical chemistry | Acoustics and Acoustical Devices; Waves
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology | Other | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in Engineering | Transport not elsewhere classified | Physical sciences |
Publisher: Emerald
Date: 22-07-2019
DOI: 10.1108/APJML-08-2018-0334
Abstract: The purpose of this paper is to investigate and develop an integrated theoretical relationship by including destination image and attitudes into the quality-value-satisfaction-loyalty paradigm in the context of beach tourism. A personal-administered survey was conducted using a convenient s ling technique to collect data from 601 tourists who had visited popular beach destinations in Bangladesh. Then, the structural relationships between the factors likely to affect tourist attitudes and loyalty were examined. The findings reveal that both service quality and perceived values have a direct effect on destination image, tourist attitudes and satisfaction. Additionally, destination image and satisfaction significantly affect tourist attitudes and loyalty. The direct relationship of perceived service quality and perceived value with tourist loyalty was ignored in the model due to reporting consecutive indirect relationship between them in prior studies. These findings contribute to the extension of theoretical and managerial knowledge, especially in a beach tourism setting, where little research has been done to investigate the proposed relationships. The originality of this study lies in providing theoretical and empirical evidence regarding the effect of service quality and perceived value, especially on destination image and tourist attitude to behaviour in the loyalty model, which has been scarcely examined in the prior tourism literature.
Publisher: American Chemical Society (ACS)
Date: 23-08-2021
Publisher: American Chemical Society (ACS)
Date: 14-11-2019
Publisher: American Chemical Society (ACS)
Date: 27-03-2018
Publisher: American Chemical Society (ACS)
Date: 04-02-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP02353K
Abstract: Coupled effects from droplet formation and the local flow dramatically enhanced the droplet growth on a microfiber in flow.
Publisher: American Chemical Society (ACS)
Date: 21-07-2020
Publisher: American Chemical Society (ACS)
Date: 25-08-2023
Publisher: American Physical Society (APS)
Date: 29-09-2022
Publisher: American Chemical Society (ACS)
Date: 18-09-2017
Publisher: Elsevier BV
Date: 09-2023
Publisher: American Chemical Society (ACS)
Date: 06-09-2022
DOI: 10.1021/ACS.LANGMUIR.2C01242
Abstract: Liquid-liquid extraction based on surface nanodroplets can be a green and sustainable technique to extract and concentrate analytes from a s le flow. However, because of the extremely small volume of each droplet (<10 fL, tens of micrometers in base radius and a few or less than 1 μm in height), only a few in situ analytical techniques, such as surface-enhanced Raman spectroscopy, were applicable for the online detection and analysis based on nanodroplet extraction. To demonstrate the versatility of surface nanodroplet-based extraction, in this work, the formation of octanol surface nanodroplets and extraction were performed inside a 3 m Teflon capillary tube. After extraction, surface nanodroplets were collected by injecting air into the tube, by which the contact line of surface droplets was collected by the capillary force. As the capillary allows for the formation of ∼10
Publisher: American Chemical Society (ACS)
Date: 25-03-2022
Publisher: American Chemical Society (ACS)
Date: 11-01-2022
Publisher: Cambridge University Press (CUP)
Date: 27-07-2021
DOI: 10.1017/JFM.2021.555
Publisher: American Chemical Society (ACS)
Date: 16-10-2020
Publisher: Elsevier BV
Date: 10-2022
Publisher: Springer Science and Business Media LLC
Date: 04-2021
Publisher: American Chemical Society (ACS)
Date: 12-07-2021
Publisher: American Chemical Society (ACS)
Date: 13-08-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SM00093K
Abstract: We present a curious effect observed during the dissolution process of water-immersed long-chain alcohol drops with an entrapped bubble. When the drop-water interface and the air bubble contact each other, a rapid cyclic motion that accelerates the drop's dissolution is found. We name this eye-catching phenomenon puffing.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2SM01275H
Abstract: Switchable hydrophilicity solvents (SHSs) are solvents defined by their ability to switch from their hydrophobic form to a hydrophilic form when brought into contact with an acidic trigger such as CO 2 .
Publisher: American Chemical Society (ACS)
Date: 14-02-2021
Publisher: American Chemical Society (ACS)
Date: 17-02-2020
Publisher: American Chemical Society (ACS)
Date: 07-03-2023
Publisher: Elsevier BV
Date: 08-2023
Publisher: American Chemical Society (ACS)
Date: 20-01-2017
Abstract: Microbubbles produced by exposing water-immersed metallic nanoparticles to resonant light play an important role in emerging and efficient plasmonic-enhanced processes for catalytic conversion, solar energy harvesting, biomedical imaging, and cancer therapy. How do these bubbles form, and what is their gas composition? In this paper, the growth dynamics of nucleating bubbles around laser-irradiated, water-immersed Au plasmonic nanoparticles are studied to determine the exact origin of the occurrence and growth of these bubbles. The microbubbles' contact angle, footprint diameter, and radius of curvature were measured in air-equilibrated water (AEW) and degassed water (DGW) with fast imaging. Our experimental data reveals that the growth dynamics can be ided into two regimes: an initial bubble nucleation phase (regime I, < 10 ms) and, subsequently a bubble growth phase (regime II). The explosive growth in regime I is identical for AEW and DGW due to the vaporization of water. However, the slower growth in regime II is distinctly different for AEW and DGW, which is attributed to the uptake of dissolved gas expelled from the water around the hot nanoparticle. Our scaling analysis reveals that the bubble radius scales with time as R(t) ∝ t
Publisher: American Chemical Society (ACS)
Date: 09-01-2019
Publisher: American Chemical Society (ACS)
Date: 18-07-2018
DOI: 10.1021/ACS.LANGMUIR.8B01252
Abstract: The crystallization of oil droplets is critical in the processing and storage of lipid-based food and pharmaceutical products. Arrays of femtoliter droplets on a surface offer a unique opportunity to study surfactant-free colloidlike systems. In this work, the crystal growth process in these confined droplets was followed by cooling a model lipid (trimyristin) from a liquid state utilizing synchrotron small-angle X-ray scattering (SAXS). The measurements by SAXS demonstrated a reduced crystallization rate and a greater degree of supercooling required to trigger lipid crystallization in droplets compared to those of bulk lipids. These results suggest that surface droplets crystallize in a stochastic manner. Interestingly, the crystallization rate is slower for larger femtoliter droplets, which may be explained by the onset of crystallization from the three-phase contact line. The larger surface nanodroplets exhibit a smaller ratio of droplet volume to the length of three-phase contact line and hence a slower crystallization rate.
Publisher: American Chemical Society (ACS)
Date: 17-01-2017
DOI: 10.1021/ACS.JPCLETT.6B02861
Abstract: Constructing controllable liquid patterns with high resolution and accuracy is of great importance in droplet depositions for a range of applications. Simple surface chemical micropatterns have been popularly used to regulate the shape of liquid droplets and the final structure of deposited materials. In this work, we study the morphological evolution of a dissolving femtoliter droplet pinned on multiple microdomains. On the basis of minimization of interfacial energy, the numerical simulations predict various symmetric droplet profiles in equilibrium at different liquid volumes. However, our experimental results show both symmetric and asymmetric shapes of droplets due to contact line pinning and symmetry breaking during droplet dissolution. Upon slow volume reduction, the deposited microdroplet arrays on one single type of simple surface prepatterns spontaneously morphed into a series of complex regular 3D shapes. The findings in this work offer insights into design and prepararion of the rich and complex morphology of liquid patterns via simple surface premicropatterns.
Publisher: Cambridge University Press (CUP)
Date: 08-05-2019
DOI: 10.1017/JFM.2019.207
Abstract: Multicomponent liquid drops in a host liquid are very relevant in various technological applications. Their dissolution or growth dynamics is complex. Differences in solubility between the drop components combined with the solutal Marangoni effect and natural convection contribute to this complexity, which can be even further increased in combination with the ouzo effect, i.e. the spontaneous nucleation of microdroplets due to composition-dependent miscibilities in a ternary system. The quantitative understanding of this combined process is important for applications in industry, particularly for modern liquid–liquid microextraction processes. In this work, as a model system, we experimentally and theoretically explore water–ethanol drops dissolving in anethole oil. During the dissolution, we observed two types of microdroplet nucleation, namely water microdroplet nucleation in the surrounding oil at drop mid-height, and oil microdroplet nucleation in the aqueous drop, again at mid-height. The nucleated oil microdroplets are driven by Marangoni flows inside the aqueous drop and evolve into microdroplet rings. A one-dimensional multiphase and multicomponent diffusion model in combination with thermodynamic equilibrium theory is proposed to predict the behaviour of spontaneous emulsification, i.e. microdroplet nucleation, that is triggered by diffusion. A scale analysis together with experimental investigations of the fluid dynamics of the system reveals that both the solutal Marangoni flow inside the drop and the buoyancy-driven flow in the host liquid influence the diffusion-triggered emulsification process. Our work provides a physical understanding of the microdroplet nucleation by dissolution of a multicomponent drop in a host liquid.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6SM02860H
Abstract: We provide an advanced understanding of the evaporation process of ouzo (multi-component) drops.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3MH00056G
Abstract: Hydrogel sensors have received massive attentions for wearable devices, recent advances in the fabrication and network structure of conductive polymer hydrogels are summarized, and their application in the field of wearable sensors is also discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7LC01321C
Abstract: The dissolution of femtoliter droplet arrays on the wall of microfluidic channels is determined by coupled effects from the collective interaction of droplets and external flow conditions. Controlled droplet dissolution enables a novel approach for the fabrication of a multifocal lens array.
Publisher: Wiley
Date: 14-09-2021
Abstract: Droplets are excellent platforms for compartmentalization of many processes such as chemical reactions, liquid–liquid extraction, and biological or chemical analyses. Accurately controlling and optimizing the composition of these droplets is of high importance to maximize their functionality. In this work, the formation of multicomponent droplets with controllable composition by employing a continuous flow‐in setup is demonstrated. Multiple streams of different oil solutions are introduced and mixed in a passive flow mixer and the outcoming mixture is subsequently fed into a flow chamber to form surface nanodroplets by solvent exchange. This method is time‐effective, enabling programmable continuous processes for droplet formation and surface cleaning. The surface nanodroplets are formed within 2.5 min in one cycle, and the droplet formation is reliable with similar size distribution over multiple cycles. The composition of the resulting surface nanodroplet can be tuned at will simply by controlling the flow rate ratios of each stream of the oil solution. Using fluorescence imaging, it is shown that the composition of the binary surface nanodroplets agrees well with theoretical values predicted using the phase diagram.
Publisher: Wiley
Date: 17-12-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7SM02490H
Abstract: The coalescence between growing droplets is important for the surface coverage and spatial arrangements of droplets on surfaces.
Publisher: American Chemical Society (ACS)
Date: 28-08-2019
Publisher: American Chemical Society (ACS)
Date: 19-11-2018
Publisher: American Chemical Society (ACS)
Date: 19-02-2021
Publisher: American Chemical Society (ACS)
Date: 31-07-2023
Publisher: American Chemical Society (ACS)
Date: 10-05-2021
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 05-2006
Abstract: We investigated the mechanisms involved in the enhancement of endothelin (ET)-1 vascular reactivity induced by ethanol consumption. Ethanol intake for 2, 6, and 10 weeks enhanced the ET-1-induced contractile response of endothelium-intact but not endothelium-denuded rat carotid rings independently of the treatment duration. Conversely, phenylephrine-induced contraction was not affected by ethanol intake. The contraction induced by IRL1620 [succinyl-(Glu(9),Ala(11,15))-ET-1-(8-21)], a selective ET(B) agonist, was increased after treatment with ethanol in endothelium-intact but not in endothelium-denuded carotid rings. Moreover, ET-1- and IRL1620-induced relaxation was reduced in endothelium-intact phenylephrine-precontracted rings from ethanol-treated rats. Acetylcholine-induced relaxation was not affected by ethanol treatment. N(G)-Nitro-l-arginine methyl ester, 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one, indomethacin, and tetraethylammonium reduced the relaxation induced by IRL1620 in carotid glands from control but not ethanol-treated rats. The mRNA levels for ET(A) and ET(B) receptors were not altered by ethanol consumption. However, ethanol treatment reduced the protein expression of ET(B) receptors. Furthermore, immunohistochemical assays showed reduced immunostaining for endothelial ET(B) receptors after treatment with ethanol. We conclude that ethanol consumption enhances ET-1-induced contraction in the rat carotid and that this response is not different among the three periods of treatment used in this study. Finally, the potentiation of ET-1-induced vascular reactivity is probably caused by reduced expression of relaxing endothelial ET(B) receptors.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SM00705E
Abstract: Solvent exchange is a simple solution-based process to produce surface nanodroplets over a large area.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2005
DOI: 10.1007/S00011-005-0003-7
Abstract: The effects of insulin on intercellular adhesion molecule (ICAM)-1-mediated leukocyte adhesion and migration were investigated. Diabetic rats (alloxan, 42 mg/kg, i. v., 42 days), matching controls, and insulin (NPH, 2 IU/day for 12 days) treated diabetic rats were used. The internal spermatic fascia of the animals was used for direct vital microscopy of the microcirculation, and for quantitation of ICAM-1 expression by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). Experiments were performed 2 h after the local injection of recombinant rat tumor necrosis factor-alpha (5 ng). Relative to controls (C), diabetic (D) rats exhibited a reduced number of adhered (D: 2.2 +/- 0.4 and C: 14.1 +/- 0.6 cells/100 microm venule length, P < 0.001) and migrated leukocytes (D: 1.1 +/- 0.3 and C: 6.3 +/- 0.6 cells/1,000 microm (2), P < 0.001) accompanied by low expression of ICAM-1 in postcapillary venules (D: 18 +/- 4 and C: 51 +/- 7 arbitrary units, P 0.05). Treatment of diabetic rats with insulin restored the number of adhered (10.9 +/- 1.2 cells/100 microm venule length), and migrated leukocytes (4.0 +/- 0.3 cells/1,000 microm (2)) as well as ICAM-1 expression (45 +/- 3 arbitrary units). Levels of mRNA for ICAM-1 remained unchanged after treatment (1.15 +/- 0.04 ICAM-1/GAPDH ratio). Insulin modulates TNF-alpha-induced ICAM-1 expression on microvascular endothelium controlling, therefore, leukocyte adhesion and migration.
Publisher: American Chemical Society (ACS)
Date: 03-01-2018
DOI: 10.1021/JACS.7B10694
Abstract: Mesoporous solids have been widely used in various biomedical areas such as drug delivery and tumor therapy. Although deformability has been recognized as a prime important characteristic influencing cellular uptake, the synthesis of deformable mesoporous solids is still a great challenge. Herein, deformable thioether-, benzene-, and ethane-bridged hollow periodic mesoporous organosilica (HPMO) nanocapsules have successfully been synthesized for the first time by a preferential etching approach. The prepared HPMO nanocapsules possess uniform diameters (240-310 nm), high surface areas (up to 878 m
Publisher: American Chemical Society (ACS)
Date: 27-07-2017
DOI: 10.1021/ACS.LANGMUIR.7B01579
Abstract: Silk is a natural polymer with a broad range of potential applications in textiles, advanced materials, biomedical devices, and drug delivery. The ability to control the morphology and assembly of silk fibroin is essential for the fabrication of silk-based structured materials. Here, we report an effective and simple approach based on droplet dissolution for weaving silk fibroin into spheres of several hundred micrometers in diameter. The spheres possess regular wrinkled microstructures on the surface and switchable transparency for visible light. To produce these silk spheres, we immersed a sessile microdrop of the silk fibroin aqueous solution in a surrounding phase of ethanol in toluene at low concentration (<10%). The droplet experienced a two-phase process: the first phase of volume expansion due to the intake of organic solvents from the surrounding phase and the second phase of droplet dissolution. The dissolution rate is closely related to the dynamics of the droplet, while the resulting microstructure of the silk microsphere is simply adjusted by the composition of the surrounding solution. At high concentrations of ethanol, silk fibroin formed a thin shell around the droplet during the initial expansion of the droplet in volume. As the droplet shrank at a later stage, the shell around the droplet wrinkled and crumpled, leading to regular ridges and crevices on the microsphere surface. This work demonstrates that controlled droplet dissolution may be explored as a novel and effective way to tailor microstructures of silk assemblies. The as-prepared silk microspheres may be potentially used as optical units or microcarriers.
Publisher: American Chemical Society (ACS)
Date: 19-05-2022
DOI: 10.1021/ACS.LANGMUIR.2C00516
Abstract: Chemical reactions in small droplets are extensively explored to accelerate the discovery of new materials and increase the efficiency and specificity in catalytic biphasic conversion and high-throughput analytics. In this work, we investigate the local rate of the gas-evolution reaction within femtoliter droplets immobilized on a solid surface. The growth rate of hydrogen microbubbles (≥500 nm in radius) produced from the reaction was measured online with high-resolution confocal microscopic images. The growth rate of bubbles was faster in smaller droplets and near the droplet rim in the same droplet. The results were consistent for both pure and binary reacting droplets and on substrates of different wettability. Our theoretical analysis based on diffusion, chemical reaction, and bubble growth predicted that the concentration of the reactant depended on the droplet size and the bubble location inside the droplet, in good agreement with experimental results. Our results reveal that the reaction rate may be spatially nonuniform in the reacting microdroplets. The findings may have implications for formulating the chemical properties and uses of these droplets.
Publisher: Elsevier BV
Date: 07-2022
Publisher: American Chemical Society (ACS)
Date: 06-03-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SM00231G
Abstract: Liquid transport in a confined space can be enhanced via propelling microdroplets. These microdroplets form spontaneously from localized liquid–liquid phase separation as a ternary mixture is diluted by a diffusing poor solvent.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CP06861A
Abstract: Growth of femtoliter droplets on the top of a microlens is in a constant contact area mode. Droplets with finely tuneable volume may be converted to composite microlens arrays with desirable optical properties.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7SM02523H
Abstract: Surface nanobubbles can be stable even when they are very close to each other.
Publisher: Wiley
Date: 05-10-2021
Publisher: American Chemical Society (ACS)
Date: 21-08-2020
Publisher: Elsevier BV
Date: 08-2023
Publisher: American Chemical Society (ACS)
Date: 19-10-2018
Publisher: Wiley
Date: 20-10-2022
Abstract: This work demonstrates an original and ultrasensitive approach for surface‐enhanced Raman spectroscopy (SERS) detection based on evaporation of self‐lubricating drops containing silver supraparticles. The developed method detects an extremely low concentration of analyte that is enriched and concentrated on sensitive SERS sites of the compact supraparticles formed from drop evaporation. A low limit of detection of 10 −16 m is achieved for a model hydrophobic compound rhodamine 6G (R6G). The quantitative analysis of R6G concentration is obtained from 10 −5 to 10 −11 m . In addition, for a model micro‐pollutant in water triclosan, the detection limit of 10 −6 m is achieved by using microliter s le solutions. The intensity of SERS detection in this approach is robust to the dispersity of the nanoparticles in the drop but became stronger after a longer drying time. The ultrasensitive detection mechanism is the sequential process of concentration, extraction, and absorption of the analyte during evaporation of self‐lubrication drop and hot spot generation for intensification of SERS signals. This novel approach for s le preparation in ultrasensitive SERS detection can be applied to the detection of chemical and biological signatures in areas such as environment monitoring, food safety, and biomedical diagnostics.
Publisher: AIP Publishing
Date: 03-2023
DOI: 10.1063/5.0141614
Abstract: Enhancing boundary slip using interfacial nanobubbles (INBs) has gained significant interest in nanofluidic transport. In this study, we conducted a comprehensive investigation on the influence of INBs on boundary conditions for both smooth and rough substrates using molecular dynamics simulations. We analyzed the impact of INB protrusion angle, coverage percentage, quantity, and fluidity on the slip length. Our results showed that INBs always increase the slip length on a smooth substrate, with a linear increase in slip length observed with increasing surface coverage. On a rough substrate, we found that the protrusion angle, quantity, and fluidity of INBs play a crucial role in determining the slip length. Smaller protrusion angles and fewer quantities of INBs were found to be more favorable for enhancing the slip length when the INB coverage is fixed, while the correlation between boundary slip and INB quantity depended on the wetting state of the substrate when the size of the INBs was fixed with a low protrusion angle. Additionally, we revealed that the fluidity of gas molecules inside the INBs dominated the enhancement of slip length by INBs. Overall, our findings are expected to provide valuable insight into drag reduction based on INBs.
Publisher: Springer Science and Business Media LLC
Date: 29-01-2019
DOI: 10.1038/S41467-019-08385-W
Abstract: The assembly of colloidal particles from evaporating suspension drops is seen as a versatile route for the fabrication of supraparticles for various applications. However, drop contact line pining leads to uncontrolled shapes of the emerging supraparticles, hindering this technique. Here we report how the pinning problem can be overcome by self-lubrication. The colloidal particles are dispersed in ternary drops (water, ethanol, and anise-oil). As the ethanol evaporates, oil microdroplets form (‘ouzo effect’). The oil microdroplets coalesce and form an oil ring at the contact line, levitating the evaporating colloidal drop (‘self-lubrication’). Then the water evaporates, leaving behind a porous supraparticle, which easily detaches from the surface. The dispersed oil microdroplets act as templates, leading to multi-scale, fractal-like structures inside the supraparticle. Employing this method, we could produce a large number of supraparticles with tunable shapes and high porosity on hydrophobic surfaces.
Publisher: American Chemical Society (ACS)
Date: 03-07-2019
Abstract: Microlens arrays are key elements for light management in optoelectronic devices. The recent advancement in the wearable intelligent electronics has driven the development of flexible microlenses. In this work, we show a controllable and scalable surface-droplet-based strategy to create unconventional flexible polymer microlens arrays. The technique is underpinned by the morphological transition of femtoliter liquid on the surface of a microlens surrounded by a planar area. We found that the droplet liquid wetted the rim of the microlens first and gradually moved upward to the microlens surface with an increase in the liquid volume. The morphology evolution of the droplet is in good agreement with the predication from our simulations based on the interfacial energy minimization under the condition of the pinned boundary. The shape of the droplet on the microlens is well controlled by the droplet volume, aspect ratio of the microlens, and the interfacial energy of the droplets on the microlens. As a result, the obtained structures of one microlens partially covered by a droplet can be produced in arrays over a large scale, serving as templates for fabricating transparent polymer double microlens arrays for improved light emission from the optoelectronic device.
Publisher: Wiley
Date: 19-09-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6LC01555G
Abstract: Control of nanodroplet size and spatial organization on a homogeneous surface by microstructures on the opposite channel.
Publisher: American Chemical Society (ACS)
Date: 26-11-2020
Publisher: American Chemical Society (ACS)
Date: 11-07-2019
DOI: 10.1021/ACS.ANALCHEM.9B02586
Abstract: The oil-water partition coefficient of organic compounds is an essential parameter for the determination of their behaviors in environments, food, drug delivery, and biomedical systems, just to name a few. In this work, we establish a highly efficient approach to quantify the partition/distribution coefficient using surface femtoliter droplets. In our approach, droplets of 1-octanol were produced on the surface of a solid substrate in contact with the flow of an aqueous solution of the analyte. The analyte was rapidly enriched in the droplets from the flow and reached the partition equilibrium in a few seconds. The entire procedure was automated by continuous solvent exchange, and the analyte partition in the droplets was quantified from the in situ UV-vis spectrum collected by a microspectrophotometer. Our approach was validated for several substances with the octanol-water partition/distribution coefficient ranging from -1.5 to 4, where our results were in good agreement with the values reported in the literature. This method took ∼3 min to detect one analyte with the volume of the organic solvent at ∼50 μL. Thus, our surface droplet platform can greatly minimize the consumption of both solvent and analytes and can shorten the time for the determination of the partition of new compounds, which overcomes the drawbacks of the traditional shake-flask method and presents excellent reproducibility, high accuracy, cost-effectiveness, and labor-saving operation. The highly efficient micro/nanoextraction, partition, and real-time detection enabled by the surface droplets has the potential for many other high-throughput applications.
Publisher: MDPI AG
Date: 27-04-2023
DOI: 10.3390/NANO13091496
Abstract: Recent developments in ultrafine bubble generation have opened up new possibilities for applications in various fields. Herein, we investigated how substances in water affect the size distribution and stability of microbubbles generated by a common nanobubble generator. By combining light scattering techniques with optical microscopy and high-speed imaging, we were able to track the evolution of microbubbles over time during and after bubble generation. Our results showed that air injection generated a higher number of microbubbles ( μm) than CO2 injection. Increasing detergent concentration led to a rapid increase in the number of microbubbles generated by both air and CO2 injection and the intensity signal detected by dynamic light scattering (DLS) slightly increased. This suggested that surface-active molecules may inhibit the growth and coalescence of bubbles. In contrast, we found that salts (NaCl and Na2CO3) in water did not significantly affect the number or size distribution of bubbles. Interestingly, the presence of oil in water increased the intensity signal and we observed that the bubbles were coated with an oil layer. This may contribute to the stability of bubbles. Overall, our study sheds light on the effects of common impurities on bubble generation and provides insights for analyzing dispersed bubbles in bulk.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1LC00139F
Abstract: We demonstrate simple and one-step extraction and detection of target compounds from slurry s les using surface nanodroplets.
Publisher: Wiley
Date: 11-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR02704D
Abstract: A sessile droplet comprising of a nanoparticle aqueous suspension in a binary solution exhibits interesting dissolution dynamics, which may be explored for the formation of toroidal or spherical nanocolloidal assemblies with highly ordered particle arrangement.
Publisher: American Chemical Society (ACS)
Date: 11-04-2022
Publisher: Springer Science and Business Media LLC
Date: 23-07-2020
Publisher: American Chemical Society (ACS)
Date: 21-12-2022
Publisher: American Chemical Society (ACS)
Date: 10-10-2022
Publisher: AIP Publishing
Date: 09-2022
DOI: 10.1063/5.0121912
Abstract: Liquid-liquid extraction based on surface nanodroplets, namely nanoextraction, can continuously extract and enrich target analytes from the flow of a s le solution. This s le preconcentration technique is easy to operate in a continuous flow system with a low consumption of organic solvent and a high enrichment factor. In this review, the evolution from single drop microextraction to advanced nanoextraction will be briefly introduced. Moreover, the formation principle and key features of surface nanodroplets will be summarized. Further, the major findings of nanoextraction combined with in-droplet chemistry toward sensitive and quantitative detection will be discussed. Finally, we will give our perspectives for the future trend of nanoextraction.
Publisher: American Chemical Society (ACS)
Date: 22-12-2022
DOI: 10.1021/ACSSENSORS.1C02076
Abstract: We report on a fluorescent-droplet-based acid-sensing scheme that allows limits of detection below 100 pM for weak acids. The concept is based on a strong partitioning of acid from an aqueous phase into octanol droplets. Using salicylic acid as a demonstration, we show that at a high concentration, the acid partitions into the organic phase by a factor of 260, which is approximately consistent with literature values. However, at lower concentrations, we obtain a partition coefficient as high as 10
Publisher: American Chemical Society (ACS)
Date: 05-10-2023
Publisher: American Chemical Society (ACS)
Date: 12-09-2022
Publisher: American Chemical Society (ACS)
Date: 16-11-2022
Publisher: American Chemical Society (ACS)
Date: 08-03-2021
Publisher: American Chemical Society (ACS)
Date: 11-11-2022
Publisher: American Chemical Society (ACS)
Date: 28-02-2020
DOI: 10.1021/JACS.9B11303
Publisher: American Chemical Society (ACS)
Date: 17-03-2018
DOI: 10.1021/ACS.LANGMUIR.8B00246
Abstract: We investigate the enhancement of the velocity of focused liquid jets by surface bubbles preformed on the inner surface of the container. The focused jets are created from the impact on a liquid-filled cylindrical tube at cavitation numbers of 0.37 (strong impact where cavitation is likely to occur on unprocessed surfaces) and 2.1 (weak impact where cavitation does not occur from the impact). The bubbles with a base diameter up to hundreds of micrometers were formed via the process of solvent exchange using air-equilibrated ethanol and water. Our measurements by high-speed imaging show that at both cavitation numbers, the jet velocities with preformed bubbles are significantly higher than those without preformed bubbles. Furthermore, our results show that after the process of solvent exchange, a large number of expanding bubbles are observed at cavitation number of 0.37, indicating that possibly both sub-millimeter and sub-micrometer bubbles on the surface contribute to the jet velocity enhancement. At the cavitation number of 2.1, the surface bubbles are observed to oscillate immediately after the impact. The measurements of the liquid pressure after the impact reveal that at both cavitation numbers, the negative pressure is d ed by the preformed surface bubbles, contributing to the increase of the jet velocity. This work sheds light on the crucial role of surface bubbles on the impulsive motion of liquids. Our findings have significant implications for the focusing jet technology, opening the opportunities for jetting fragile s les such as biological s les.
Publisher: Elsevier BV
Date: 08-2022
Publisher: American Chemical Society (ACS)
Date: 16-05-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SM00638A
Abstract: Moving contact lines of more than two phases dictate a large number of interfacial phenomena.
Publisher: Wiley
Date: 22-10-2023
Publisher: Proceedings of the National Academy of Sciences
Date: 11-09-2017
Abstract: The phenomenon of spontaneous nanodroplet formation termed the “Ouzo effect” is the basis for many processes, from preparation of pharmaceutical products, to formulation of cosmetics and insecticides, to liquid–liquid microextraction. This work attempts to disentangle the effects of concentration gradients from the extrinsic mixing dynamics by spatiotemporally following the nanodroplet formation from the Ouzo effect confined in a quasi-2D geometry. We observe striking universal branch structures of the nucleating droplets under the external diffusive field, analogous to the ramification of stream networks in large scale, and the enhanced local mobility of colloidal particles driven by the concentration gradient emerging from the development of the branch patterns. We further demonstrate that these nanodroplets can be exploited for single-step nanoextraction and detection.
Publisher: Elsevier BV
Date: 10-2022
Publisher: American Chemical Society (ACS)
Date: 14-03-2022
Publisher: American Chemical Society (ACS)
Date: 02-02-2021
Publisher: American Chemical Society (ACS)
Date: 23-06-2021
Publisher: Elsevier BV
Date: 11-2023
Publisher: AIP Publishing
Date: 2023
DOI: 10.1063/5.0132129
Abstract: Pipeline transport is commonly used in the oil sand industry to convey crushed oil sand ores and tailings. Bitumen residues in the oil sand tailings can be a threat to the environment that separating them from tailings before disposal is crucial. However, low bitumen concentration in the tailing slurry and the complex transport characteristics of the four-phase mixture make the process difficult. This study establishes an Eulerian–Eulerian (E–E) computational fluid dynamics model for an industrial-scale oil sand tailings pipeline. A comprehensive sensitivity analysis was conducted on the selection of carrier-solid and solid-bitumen drag models. The combination of small and large particle sizes (i.e., 75 and 700 μm) and bitumen droplet size (i.e., 400 μm) provided good agreement with field data in velocity profiles and pressure drop. The validated model was subsequently extended to investigate the influence of the secondary phase (i.e., bitumen droplets and bubbles) on flow characteristics in a tailing pipeline. The investigation covered a range of bitumen droplet size (100–400 μm), bitumen fraction (0.0025–0.1), bubble size (5–1000 μm), and bubble fraction (0.0025–0.3) and their influences on the velocity, solids, and bitumen distribution are revealed. For an optimum bubble size of 500 μm, a maximum recovery of 59% from the top 50% and 83% from the top 75% of the pipe cross section was obtained. The present study demonstrates the preferential distribution of bitumen and provides valuable insight into bitumen recovery from an industrial-scale tailing pipeline.
Publisher: Wiley
Date: 28-11-2019
Abstract: A universal femtoliter surface droplet-based platform for direct quantification of trace of hydrophobic compounds in aqueous solutions is presented. Formation and functionalization of femtoliter droplets, concentrating the analyte in the solution, are integrated into a simple fluidic chamber, taking advantage of the long-term stability, large surface-to-volume ratio, and tunable chemical composition of these droplets. In situ quantification of the extracted analytes is achieved by surface-enhanced Raman scattering (SERS) spectroscopy by nanoparticles on the functionalized droplets. Optimized extraction efficiency and SERS enhancement by tuning droplet composition enable quantitative determination of hydrophobic model compounds of rhodamine 6G, methylene blue, and malachite green with the detection limit of 10
Publisher: American Chemical Society (ACS)
Date: 13-04-2018
Publisher: Wiley
Date: 28-08-2023
DOI: 10.1002/DRO2.82
Abstract: Switchable hydrophilicity solvents (SHSs) are a unique class of chemical compounds that can be switched between their hydrophobic and hydrophilic forms. The switchable characteristics allow SHSs to be used as emerging, green solvents for sustainable extraction and separation technology. In the production of polymeric microparticles from recycled plastics, SHSs are used to dissolve the polymer and then are switched to the hydrophilic form for separation from the generated polymeric microparticles. However, it is extremely difficult to fully recover the SHS residue from the mixtures. In this work, we will identify the key parameters that determine the level of the solvent residue during the switched‐on dissolution of emulsion microdroplets. The SHS N,N ‐dimethylcyclohexylamine from solvent–polymer binary emulsion droplets was switched to the hydrophilic, water‐soluble form, triggered by addition of an acid in the surrounding aqueous phase. By applying a sensitive detection method developed in this work, we compared the levels of SHS residue in polymer microparticles obtained under 30 different dynamical and chemical conditions for the switching processes. The quantitative analysis revealed that residue levels remained constant at varied addition rates and concentration of the trigger solution, but decreased with the increase in organic phase fractions or the decrease in the emulsion temperature. Trapped water in the drops during switched‐on dissolution may have contributed to the high level of solvent residue. The understanding of the new possible mechanism for residual solvent reported in this work may help develop effective approaches for the recovery of switchable solvents in environmentally friendly separation processes.
Publisher: American Chemical Society (ACS)
Date: 16-12-2029
DOI: 10.1021/ACS.LANGMUIR.9B01051
Abstract: Droplets at solid-liquid interfaces play essential roles in a broad range of fields, such as compartmentalized chemical reactions and conversions, high-throughput analysis and sensing, and super-resolution near-field imaging. Our recent work has focused on understanding and controlling the nanodroplet formation on solid surfaces in ternary liquid mixtures. These surface nanodroplets resemble tiny liquid lenses with a typical height of <1 μm and a volume of subfemtoliters. The solvent exchange is based on the process of displacing a droplet liquid solution by a poor solvent to create a transient oversaturation for droplet formation. A quantitative understanding of growth dynamics of surface nanodroplets in ternary liquid mixtures not only provides insight into the liquid-liquid phase separation induced by solvent addition in general but also has made it possible to control the droplet size well. This review article will summarize our findings in the last ∼5 years from the research with our collaborators. The first part will explain the fundamental aspects that are key to the formation and stability of surface nanodroplets. In the second part, we will highlight the applications of nanodroplets in chemical analysis and functional surface fabrication and finally point out future directions in droplet-based applications.
Publisher: American Chemical Society (ACS)
Date: 23-04-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0LC00571A
Abstract: The kinetics of a model biphasic reaction at the interface of surface nanodroplets is quantitatively studied. The droplet reaction time scales with ∼Pe −2/3 of the reactant flow. Enhanced mass transport contributes to accelerated kinetics.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3TB00639E
Abstract: This review article provides an overview of types of wound dressings, wound-dressing materials, advanced fabrication techniques, and key features and applications of transparent dressings for the healing process, as well as how they can improve healing outcomes.
Start Date: 04-2023
End Date: 04-2026
Amount: $432,307.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2012
End Date: 12-2017
Amount: $714,528.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 12-2017
Amount: $410,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 05-2008
End Date: 04-2012
Amount: $362,000.00
Funder: Australian Research Council
View Funded Activity