Nanofiller-tuned microporous polymer molecular sieves for energy and environmental processes

10.1039/c5ta09060aJournal of Materials Chemistry A41270-27

Regulating the aqueous phase monomer balance for flux improvement in polyamide thin film composite membranes

Polyamide thin film composite (PA TFC) membranes are synthesized from interfacial polymerization using two amines in the aqueous phase. The conventional monomer, mphenelynediamine (MPD), is partially replaced by a linear monomer, 1,3–diamino-2- hydroxypropane (DAHP). The water permeability of the membranes improves by around 22 % (to 2.67 ± 0.09 L.m-2.h-1.bar-1) while keeping the same high salt rejection (96-98%) at an optimum DAHP/MPD ratio of 12.8 %. While developing the control PA TFC membrane we introduce a washing step and show that the support surface should be free from surface protective coatings to achieve high water flux (2.18 ± 0.08 L.m-2.h-1.bar-1). Incorporating DAHP units into the polyamide network improves the water flux through the membranes fabricated on both original and washed supports. The surface morphologies of polyamide films change significantly with introduction of DAHP, from large ridge-and-valley structure to enlarged nodular structures. High resolution SEM images show an ultrathin polyamide thin film with a thickness that is reduced with addition of DAHP. These influences of DAHP, namely a reduction in the selective layer thickness, an alteration in surface morphology, changes in internal molecular packing and hydrophilicity, are suggested as factors behind the improved water permeability.We would like to thank EPSRC grant, Schlumberger Faculty for the Future (FFTF) foundation and the Qatar National Research Fund for the research financial support.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S0376738815002161

REMOVED: High Performance Gas Separation Membrane from a Polymer of Intrinsic Microporosity by Photochemical Surface Modification

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)

Enhanced selectivity in mixed matrix membranes for CO2 capture through efficient dispersion of amine-functionalized MOF nanoparticles

Mixed matrix membranes (MMMs) for gas separation applications have enhanced selectivity when compared with the pure polymer matrix, but are commonly reported with low intrinsic permeability, which has major cost implications for implementation of membrane technologies in large-scale carbon capture projects. High-permeability polymers rarely generate sufficient selectivity for energy-efficient CO2 capture. Here we report substantial selectivity enhancements within high-permeability polymers as a result of the efficient dispersion of amine-functionalized, nanosized metal–organic framework (MOF) additives. The enhancement effects under optimal mixing conditions occur with minimal loss in overall permeability. Nanosizing of the MOF enhances its dispersion within the polymer matrix to minimize non-selective microvoid formation around the particles. Amination of such MOFs increases their interaction with thepolymer matrix, resulting in a measured rigidification and enhanced selectivity of the overall composite. The optimal MOF MMM performance was verified in three different polymer systems, and also over pressure and temperature ranges suitable for carbon capture

Thin, flexible supercapacitors made from carbon nanofiber electrodes decorated at room temperature with manganese oxide nanosheets

We report the fabrication and electrochemical performance of a flexible thin film supercapacitor with a novel nanostructured composite electrode. The electrode was prepared byin situcoprecipitation of two-dimensional (2D) MnO2nanosheets at room temperature in the presence of carbon nanofibers (CNFs). The highest specific capacitance of 142 F/g was achieved for CNFs-MnO2electrodes in sandwiched assembly with PVA-H4SiW12O40·nH2O polyelectrolyte separator.Peer Reviewe

Thin, flexible supercapacitors made from carbon nanofiber electrodes decorated at room temperature with manganese oxide nanosheets

We report the fabrication and electrochemical performance of a flexible thin film supercapacitor with a novel nanostructured composite electrode. The electrode was prepared by in situ coprecipitation of two-dimensional (2D) MnO2 nanosheets at room temperature in the presence of carbon nanofibers (CNFs). The highest specific capacitance of 142 F/g was achieved for CNFs-MnO2 electrodes in sandwiched assembly with PVA-H4SiW12O40.nH2O polyelectrolyte separator

In vitro production of polyhydroxyalkanoates: achievements and applications

The mechanisms of polyhydroxyalkanoate (PHA) production have been studied for over half a century. However, despite numerous improvements in the control of monomer composition, genetically-engineered host organisms, fermentation strategies and polymer recovery processes they remain uncompetitive compared with petrochemical plastics. Recently, interest has developed in the enzyme-catalysed production of PHAs in vitro. This has allowed the study of enzyme kinetics and properties, and represents another strategy for the economic production of PHAs on the industrial scale. It also presents an opportunity to coat other materials in thin films of PHA so as to modify the surface properties. In vitro production offers advantages over in vivo methods as it enables greater control over monomer composition and molecular weight, does not require a biomass-accumulation phase, simplifies downstream processing and can utilise a wider range of monomeric subunits

Early stages of polymer interdiffusion

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