Crosslinked organic/inorganic proton exchange membranes with multilayer structure

Organic/inorganic proton exchange membranes with multilayer structure based on silicon-containing sulfonated polystyrene/acrylate (SisPS/A) and chitosan (CS) are prepared by the layer-by-layer deposition technique. Then the multilayers are heat-induced to fabricate the crosslinked membrane structure. Scanning electron microscope micrograph shows the presence and stability of the thin layers coated on the SisPS/A substrate. Fourier transform infrared spectroscopy confirms the interaction between SisPS/A and CS molecules and the existence of crosslinked silica network structure in the multilayer systems. In comparison with the pure SisPS/A and Nafion® 117 membranes, the crosslinked organic/inorganic multilayer proton exchange membranes (c-SisPS/A-CS) display better methanol barrier and higher selectivity (conductivity/methanol diffusion coefficient). The methanol diffusion coefficient and selectivity of 15 bilayered c-SisPS/A-CS are 9.20 × 10− 8 cm2 s− 1 and 1.90 × 105 Ss cm− 3, respectively, which are attractive in direct methanol fuel cell applications.

► The crosslinked organic/inorganic proton exchange membranes with multilayer structure are prepared. ► The multilayer membranes show good methanol barrier and selectivity. ► Increasing the number of bilayers will decrease methanol diffusion coefficient. ► Increasing the number of bilayers will increase selectivity. ► LbL self-assembly and crosslinking are effective in improving membrane performance.