ORCID Profile
0000-0003-1368-1506
Current Organisation
The University of Edinburgh
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Chemical Society (ACS)
Date: 07-07-2017
Publisher: American Chemical Society (ACS)
Date: 29-01-2021
Publisher: Wiley
Date: 23-03-2023
Abstract: Incorporating photo‐switches into skeletal structures of microporous materials or as guest molecules yield photo‐responsive materials for low‐energy CO 2 capture but at the expense of lower CO 2 uptake. Here, we overcome this limitation by exploiting trans – cis photoisomerization of azobenzene loaded into the micropores of hypercross‐linked polymers (HCPs) derived from waste polystyrene. Azobenzene in HCP pores reduced CO 2 uptake by 19 %, reaching 37.7 cm 3 g −1 , but this loss in CO 2 uptake was not only recovered by trans – cis photoisomerization of azobenzene, but also increased by 22 %, reaching 56.9 cm 3 g −1 , when compared to as‐prepared HCPs. Computational simulations show that this increase in CO 2 uptake is due to photo‐controlled increments in 10–20 Å micropore volume, i. e., adsorption sites and a photo‐reversible positive dipole moment. Irradiating these HCPs with visual‐range light reverted CO 2 uptake to 33 cm 3 g −1 . This shows that it is feasible to recycle waste polystyrene into advanced materials for low‐energy carbon capture.
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 02-2015
Publisher: Wiley
Date: 16-04-2014
Abstract: Aging in super glassy polymers such as poly(trimethylsilylpropyne) (PTMSP), poly(4-methyl-2-pentyne) (PMP), and polymers with intrinsic microporosity (PIM-1) reduces gas permeabilities and limits their application as gas-separation membranes. While super glassy polymers are initially very porous, and ultra-permeable, they quickly pack into a denser phase becoming less porous and permeable. This age-old problem has been solved by adding an ultraporous additive that maintains the low density, porous, initial stage of super glassy polymers through absorbing a portion of the polymer chains within its pores thereby holding the chains in their open position. This result is the first time that aging in super glassy polymers is inhibited whilst maintaining enhanced CO2 permeability for one year and improving CO2/N2 selectivity. This approach could allow super glassy polymers to be revisited for commercial application in gas separations.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA00871K
Abstract: The incompatibility between PVA and PTFE layers was overcome by spray-coating and the PVA/PTFE composite membrane showed excellent desalination properties in both PV and DCMD experiments.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2TA09253K
Abstract: Continuous flow synthesis of hypercrosslinked polymers (HCPs) was achieved within 5 minutes, 99% faster than a batch reaction, improving productivity rates by 32-fold. The faster kinetics also enhanced microporosity, increasing CO 2 /N 2 selectivity by 850%.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 27-03-2023
DOI: 10.1038/S41467-023-37479-9
Abstract: Advances in membrane technologies are significant for mitigating global climate change because of their low cost and easy operation. Although mixed-matrix membranes (MMMs) obtained via the combination of metal-organic frameworks (MOFs) and a polymer matrix are promising for energy-efficient gas separation, the achievement of a desirable match between polymers and MOFs for the development of advanced MMMs is challenging, especially when emerging highly permeable materials such as polymers of intrinsic microporosity (PIMs) are deployed. Here, we report a molecular soldering strategy featuring multifunctional polyphenols in tailored polymer chains, well-designed hollow MOF structures, and defect-free interfaces. The exceptional adhesion nature of polyphenols results in dense packing and visible stiffness of PIM-1 chains with strengthened selectivity. The architecture of the hollow MOFs leads to free mass transfer and substantially improves permeability. These structural advantages act synergistically to break the permeability-selectivity trade-off limit in MMMs and surpass the conventional upper bound. This polyphenol molecular soldering method has been validated for various polymers, providing a universal pathway to prepare advanced MMMs with desirable performance for erse applications beyond carbon capture.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR04801A
Abstract: Membranes are crucial to lowering the huge energy costs of chemical separations.
Publisher: Elsevier BV
Date: 05-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA02603F
Abstract: Addressing the mechanical weakness and physical aging of glassy mixed matrix membranes to realise their potential for enhancing the separation performance of current membrane technologies.
Publisher: Elsevier BV
Date: 10-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2TA07200A
Abstract: Spray coating creates highly porous polymer films that enhance pure water permeance by 7-fold, overcoming the trade-off between poor desalination performances and the sustainability offered by using green solvents in polymer membrane fabrication.
Publisher: Wiley
Date: 08-01-2016
Abstract: The loss of internal pores, a process known as physical aging, inhibits the long-term use of the most promising gas-separation polymers. Previously we reported that a porous aromatic framework (PAF-1) could form a remarkable nanocomposite with gas-separation polymers to stop aging. However, PAF-1 synthesis is very onerous both from a reagent and reaction-condition perspective, making it difficult to scale-up. We now reveal a highly dispersible and scalable additive based on α,α'-dichloro-p-xylene (p-DCX), that inhibits aging more effectively, and crucially almost doubles gas-transport selectivity. These synergistic effects are related to the intimately mixed nanocomposite that is formed though the high dispersibility of p-DCX in the gas-separation polymer. This reduces particle-size effects and the internal free volume is almost unchanged over time. This study shows this inexpensive and scalable polymer additive delivers exceptional gas-transport performance and selectivity.
Publisher: American Chemical Society (ACS)
Date: 15-04-2019
Abstract: Biofouling can be overcome with zwitterion grafts and antimicrobial, metallic nanoparticles. However, the mechanism underpinning this effective approach remains unclear. To elucidate the role of each component in this system while maximizing membrane antifouling and antimicrobial properties, here we performed a comparative study to investigate the impact of zwitterion type and their interactions with Ag of various states. Two different zwitterions (SO
Publisher: American Chemical Society (ACS)
Date: 26-10-2017
Abstract: Membrane separation is a promising technology for extracting temperature-sensitive organic molecules from solvents. However, a lack of membrane materials that are permeable toward organic solvents yet highly selective curtails large-scale membrane applications. To overcome the trade-off between flux and selectivity, additional molecular transportation pathways are constructed in ultrathin polyamide membranes using highly hydrostable metal organic frameworks with erse functional surface architectures. Additional passageways enhance water permeance by 84% (15.4 L m
Publisher: Elsevier BV
Date: 09-2010
Publisher: American Chemical Society (ACS)
Date: 24-02-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA02286J
Abstract: The effect of controlling interactions between the components in a mixed-matrix membrane at the molecular level has been explored.
Publisher: American Chemical Society (ACS)
Date: 29-04-2015
Abstract: We first report here mussel-inspired, hybrid coatings formed in a facile manner via simultaneous polymerization of mussel-inspired dopamine and hydrolysis of commercial tetraethoxysilane in a single-step process. The hybrid coatings can firmly adhered on hydrophobic polyvinylidene fluoride (PVDF) substrate, and the hydrophilicity of the coating can be tuned by adjusting silane concentration. The reason for the changed hydrophilicity of the coating is disclosed by a series of characterization, and was applied to rationally design optimized hybrid coatings that transform commercial PVDF microfiltration (MF) membrane hydrophobicity into high hydrophilicity with excellent water permeability and underwater superoleophobicity for oil-in-water emulsion separation. The PVDF MF membrane decorated with optimized coatings has ultrahigh water flux (8606 L m(-2) h(-1) only under 0.9 bar, which is 34 times higher than that of pristine membrane), highly efficient oil-in-water emulsion separation ability at atmospheric pressure (filtrate flux of 140 L m(-2) h(-1)) and excellent antifouling performance. More importantly, these membranes are extremely stable as underwater superoleophobicity are maintained, even after rigorous washings or cryogenic bending, disclosing outstanding stability. The simplicity and versatility of this novel mussel-inspired one-step strategy may bridge the material-induced technology gap between academia and industry, which makes it promising for eco-friendly applications.
Publisher: American Chemical Society (ACS)
Date: 05-06-2023
Publisher: Wiley
Date: 14-06-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA05970K
Abstract: Simultaneous polymerization of dopamine and hydrolysis of commercial γ-(2,3-epoxypropoxy)propytrimethoxysilane can endow membranes with exceptional wettability towards harsh water treatment.
Publisher: American Chemical Society (ACS)
Date: 19-04-2019
Abstract: Current forward osmosis (FO) membranes are unsuitable for arsenic removal from water because of their poor arsenic selectivity. In this study, we designed and synthesized a series of novel imidazolium-based ionic liquids via one-step quaternization reactions and grafted these novel compounds on to conventional thin-film composite FO membranes for treatment of arsenic-containing water. The newly developed ionic membranes contained a functionalized selective polyamide layer grafted with either carboxylic acid/carboxylate or sulfonate groups that drastically enhanced membrane hydrophilicity and thus FO water permeation. Ionic membranes modified with sodium 1-ethanesulfonate-3-(3-aminopropyl) imidazolium bromide (NH
Publisher: IOP Publishing
Date: 2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC03731D
Abstract: By replacing Lewis acids with Brønsted acids as catalysts, continuous flow synthesis of hypercrosslinked polymers is achieved within 10% of the time required for a typical batch reaction. Compared with batch-synthesised polymers, the flow-produced materials take up 24% more CO2, precluding the need for lengthy reaction protocols to yield high-performance hypercrosslinked polymers for carbon capture.
Publisher: American Chemical Society (ACS)
Date: 02-06-2020
Publisher: American Chemical Society (ACS)
Date: 15-06-2011
DOI: 10.1021/MA200885K
Publisher: American Chemical Society (ACS)
Date: 05-07-2011
DOI: 10.1021/MA201083M
Publisher: Springer Science and Business Media LLC
Date: 18-03-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA06070A
Abstract: The attractive intermolecular interactions between PIM-1 and polycyclic aromatic hydrocarbons were used to produce films with higher CO 2 /N 2 gas sorption selectivity and reduced ageing of permeability.
Publisher: American Chemical Society (ACS)
Date: 17-01-2019
Abstract: Membranes are particularly attractive for lowering the energy intensity of separations as they eliminate phase changes. While many tantalizing polymers are known, limitations in selectivity and stability slightly preclude further development. Mixed-matrix membranes may address these shortcomings. Key to their realization is the intimate mixing between the polymer and the additive to eliminate nonselective transport, improve selectivity, and resist physical aging. Polymers of intrinsic microporosity (PIMs) have inherently promising gas transport properties. Here, we show that porous additives can improve transport and resist aging in PIM-1. We develop a simple, low-cost, and scalable hyper-cross-linked polymer (poly-dichloroxylene, pDCX), which was hydroxylated to form an intimate mixture with the polar PIM-1. Solvent variation allowed control of physical aging rates and improved selectivity for smaller gases. This detailed study has allowed many interactions within mixed matrix membranes to be directly elucidated and presents a practical means to stabilize porous polymers for separation applications.
Publisher: Wiley
Date: 13-01-2015
Abstract: Porosity loss, also known as physical aging, in glassy polymers h ers their long term use in gas separations. Unprecedented interactions of porous aromatic frameworks (PAFs) with these polymers offer the potential to control and exploit physical aging for drastically enhanced separation efficiency. PAF-1 is used in the archetypal polymer of intrinsic microporosity (PIM), PIM-1, to achieve three significant outcomes. 1) hydrogen permeability is drastically enhanced by 375% to 5500 Barrer. 2) Physical aging is controlled causing the selectivity for H2 over N2 to increase from 4.5 to 13 over 400 days of aging. 3) The improvement with age of the membrane is exploited to recover up to 98% of H2 from gas mixtures with N2 . This process is critical for the use of ammonia as a H2 storage medium. The tethering of polymer side chains within PAF-1 pores is responsible for maintaining H2 transport pathways, whilst the larger N2 pathways gradually collapse.
Publisher: American Chemical Society (ACS)
Date: 26-06-2015
Publisher: American Chemical Society (ACS)
Date: 05-07-2020
Publisher: Springer Science and Business Media LLC
Date: 09-05-2023
DOI: 10.1038/S41467-023-38419-3
Abstract: Here, we present a proactive fouling prevention mechanism that endows superhydrophilic membranes with antifouling capability against migratory viscous crude oil fouling. By simulating the hierarchical architecture/chemical composition of a dahlia leaf, a membrane surface is decorated with wrinkled-pattern microparticles, exhibiting a unique proactive fouling prevention mechanism based on a synergistic hydration layer/steric hindrance. The density functional theory and physicochemical characterizations demonstrate that the main chains of the microparticles are bent towards Fe 3+ through coordination interactions to create nanoscale wrinkled patterns on smooth microparticle surfaces. Nanoscale wrinkled patterns reduce the surface roughness and increase the contact area between the membrane surface and water molecules, expanding the steric hindrance between the oil molecules and membrane surface. Molecular dynamic simulations reveal that the water-molecule densities and strengths of the hydrogen bonds are higher near the resultant membrane surface. With this concept, we can successfully inhibit the initial adhesion, migration, and deposition of oil, regardless of the viscosity, on the membrane surface and achieve migratory viscous crude oil antifouling. This research on the PFP mechanism opens pathways to realize superwettable materials for erse applications in fields related to the environment, energy, health, and beyond.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC40470F
Abstract: CO2 uptake in zirconium MOF UiO-66 almost doubles with post-synthetic exchange of Zr by Ti. This was due to smaller pore size and higher adsorption enthalpy, with good complementarity between experiment and simulation. Furthermore, the full effect is obtained with ~50% Ti loading, precluding the need to fully substitute frameworks for CO2 capture.
Publisher: Springer Science and Business Media LLC
Date: 16-01-2015
DOI: 10.1038/SREP07823
Publisher: American Chemical Society (ACS)
Date: 11-04-2017
Abstract: Membrane materials with high permeability to solvents while rejecting dissolved contaminants are crucial to lowering the energy costs associated with liquid separations. However, the current lack of stable high-permeability materials require innovative engineering solutions to yield high-performance, thin membranes using stable polymers with low permeabilities. Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) is one of the most permeable polymers but is extremely susceptible to physical aging. Despite recent developments in anti-aging polymer membranes, this research breakthrough has yet to be demonstrated on thin PTMSP films supported on porous polymer substrates, a crucial step toward commercializing anti-aging membranes for industrial applications. Here we report the development of scalable, thin film nanocomposite membranes supported on polymer substrates that are resistant to physical aging while having high permeabilities to alcohols. The selective layer is made up of PTMSP and nanoporous polymeric additives. The nanoporous additives provide additional passageways to solvents, enhancing the high permeability of the PTMSP materials further. Through intercalation of polyacetylene chains into the sub-nm pores of organic additives, physical aging in the consequent was significantly hindered in continuous long-term operation. Remarkably we also demonstrate that the additives enhance both membrane permeability and rejection of dissolved contaminants across the membranes, as ethanol permeability at 5.5 × 10
Publisher: American Chemical Society (ACS)
Date: 28-02-2018
Abstract: The potential of forward osmosis for water treatment can only be maximized with suitable draw solutes. Here a three-dimensional, multicharge draw solute of decasodium phytate (Na
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3TA04553F
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Cher Hon Lau.