Polymer electrolyte membranes with high selectivity based on silicon-containing sulfonated polystyrene/acrylate, poly(vinyl alcohol) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid)

• The organic/inorganic composite membranes are prepared by blending and crosslinking.
• The composite membranes possess excellent thermal stability and methanol barrier.
• The selectivity of composite membranes is much higher than that of Nafion® 117.
• The composite membranes are particularly promising for DMFC applications.

A series of crosslinked organic/inorganic composite membranes are prepared from silicon-containing sulfonated polystyrene/acrylate, poly(vinyl alcohol) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) by blending and crosslinking. The potential of composite membranes as polymer electrolyte membranes in direct methanol fuel cells (DMFCs) is preliminarily assessed. It is found that these membranes possess excellent thermal stability and methanol barrier. Their methanol diffusion coefficient can be as low as 7.82 × 10−8 cm2 s−1, which is only about 1/30th of that (2.36 × 10−6 cm2 s−1) of Nafion® 117. In addition, the proton conductivity of the composite membranes is of the order of 10−2 S cm−1 and all the membranes show much higher selectivity in comparison with Nafion® 117. The highest selectivity value is 3.48 × 105 S cm−3, which is approximately 16.3 times of that (2.13 × 104 S cm−3) of Nafion® 117. These results indicate that the polymer electrolyte membranes fabricated in this work will be particularly promising for DMFC applications.