Water self-diffusion anisotropy and electrical conductivity of perfluorosulfonic acid/SiO2 composite proton exchange membranes

Poly(vinylamine-co-N-isopropylacrylamide) linear polymer and hydrogels with tuned thermoresponsivity

The fabrication of functional hydrogels with tuned thermoresponsivity is a major challenge. To meet this challenge we copolymerize N-isopropylacrylamide (NIPAm) with N-vinylformamide (NVF) in different ratios with the formamide group being subsequently selectively hydrolyzed to the corresponding amine (VAm). The copolymers are crosslinked with phenylcarbonate telechelic glycol. The influence of the NIPAm : VAm ratio on the thermoresponsitiviy is investigated in terms of absorbance, rheology, NMR spectroscopy, relaxometry, and diffusometry. Phase transition temperatures, change in the entropy of the polymer-water system, and width of the transition in the process of coil-to-globule and swollen-to-collapsed network transitions were evaluated by a two state model and Boltzmann sigmoidal function.

Humidity-induced formation of water channels in supramolecular assemblies of wedge-shaped amphiphiles: the effect of the molecular architecture on the channel topology

Absorption of water by wedge-shaped amphiphilic mesogens results in the formation of nanometer-sized water channels in the supramolecular structure that can have 1D or 2D-shape.

Synthesis of highly stable and high water retentive functionalized biopolymer-graphene oxide modified cation exchange membranes

Usage of polymer electrolyte membranes in energy based devices is substituting the conventional electrolytes.

SGO/SPES-based highly conducting polymer electrolyte membranes for fuel cell application

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.