Proton-exchange membranes (PEMs) consisting of sulfonated poly(ether sulfone) (SPES) with enhanced electrochemical properties have been successfully prepared by incorporating different amount of sulfonated graphene oxide (SGO). Composite membranes are tested for proton conductivity (30-90 °C) and methanol crossover resistance to expose their potential for direct methanol fuel cell (DMFC) application. Incorporation of SGO considerably increases the ion-exchange capacity (IEC), water retention and proton conductivity and reduces the methanol permeability. Membranes have been characterized by FTIR, XRD, DSC, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in composite membranes are established by FTIR. The distribution of SGO throughout the membrane matrix has been examined using SEM and TEM and found to be uniform. The maximum proton conductivity has been found in 5% SGO composite with higher methanol crossover resistance.

Nanohybrid membranes of electrically aligned functionalized carbon nanotube f CNT with sulfonated poly ether ether ketone (SPEEK) have been successfully prepared by solution casting. Functionalization of CNTs was done through a carboxylation and sulfonation route. Further, a constant electric field (500 V·cm(-2)) has been applied to align CNTs in the same direction during the membrane drying process. All the membranes are characterized chemically, thermally, and mechanically by the means of FTIR, DSC, DMA, UTM, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in hybrid membranes are established by FTIR. Physicochemical measurements were done to analyze membrane stability. Membranes are evaluated for proton conductivity (30-90 °C) and methanol crossover resistance to reveal their potential for direct methanol fuel cell application. Incorporation of f CNT reasonably increases the ion-exchange capacity, water retention, and proton conductivity while it reduces the methanol permeability. The maximum proton conductivity has been found in the S-sCNT-5 nanohybrid PEM with higher methanol crossover resistance. The prepared membranes can be also used for electrode material for fuel cells and batteries.

Different membrane properties by inclusion of graphene oxide content.

No abstract

Boron nitride (BN) is an exciting material and has drawn the attention of researchers for the last decade due to its surprising properties, including large surface area, thermomechanical stability, and high chemical resistance.

A series of polymer electrolytes of sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (sPPO) in combination with two-dimensional sulfonated boron nitride (s-BN) has been synthesized to form composite polymer electrolytes for direct methanol fuel cell (DMFC). The sulfonation of boron nitride (BN) has been confirmed by XPS, FT-IR, and elemental analysis. The composite membranes have been characterized for their water content, ion transport phenomenon, and thermo-mechanical stabilities along with methanol crossover resistance. Further, s-BN shows good dispersion in sPPO composite membranes by forming amplified longrange ionic clusters via hydrophilic or hydrogen bonding interaction between the s-BN and sPPO matrix. The optimized s-BN/sPPO (5 wt %) composite membrane reveals 67% higher proton conductivity and one-third methanol permeability compared to pristine sPPO membrane. The s-BN/sPPO (5 wt %) composite membrane presents a DMFC peak power density of 122 mW/cm 2 , which is higher than the peak power densities of 88 and 60 mW/cm 2 for Nafion 117 and pristine sPPO, respectively. The preferential increase in electrochemical selectivity of composite membranes suggests their potential in DMFCs.

We report the synthesis of an anion exchange membrane (AEM) based on chemically covalently modified graphene oxide (GO) for electrodialysis and fuel cell applications.

A new siloxane monomer, 3-(3-(diethoxy(2-(5-(4-(10-ethoxy-4-hydroxy-2,2-dimethyl-11-oxa-2-ammonio-6-aza-10-silatridecan-10-yl)phenyl)-1,3,4-oxadi azol-2-ylthio)ethyl)silyl)propylamino)-2-hydroxy-N,N,N-trimethylpropan-1-aminium chloride (OA), was synthesized by reported 3-((4-(5-(2-((3-aminopropyl) diethoxysilyl)ethylthio)-1,3,4-oxadiazol-2-yl)phenyl) diethoxysilyl)propan-1-amine (APDSMO) and glycidyltrimethylammonium chloride (GDTMAC) by epoxide ring-opening reaction. OA-poly(vinyl alcohol) (PVA) hybrid antibiofouling nanofilter (NF) membranes were prepared by acid-catalyzed sol-gel followed by formal cross-linking. Membranes showed wormlike arrangement and self-assembled layered morphology with varying OA content. Hybrid NF membrane, especially OA-6, showed low surface roughness, high hydrophilic nature, low biofouling, high cross-linking density, thermal and mechanical stablility, solvent- and chlorine-tolerant nature, along with good permeability and salt rejection. Prepared OA-6 hybrid NF membrane can be used efficiently for desalting and purification of water with about 2.0 g/L salt content (groundwater in major part of India). The described method provides novel route for producing antibiofouling membranes of diversified applications.