PVA/silica membranes were synthesized by the sol-gel process under acidic conditions. Tetraethoxysilane (TEOS) was used as precursor with concentration between 5 and 30% in two distinct systems. One system was used as control, which contained only PVA / TEOS. In the second system, groups necessary for conductivity were introduced with 12% by weight of hydrated phosphotungstic heteropolyacid (HPW) in relation to the mass of TEOS. The evaluations of the degree of swelling, permeability for ethanol and proton conductivity have shown that the membrane containing 30 wt% TEOS gives the best results among the membranes produced. The best results achieved in this study were 0.28 mS / cm of proton conductivity and 1.5 kg/m².h flux of ethanol solution. Thus, under these conditions, crosslinked membranes with PVA/SiO2 and TEOS precursor are good alternative for crosslinking PVA membranes since they were more selective to the flow of ethanol solution. However, for applications such as in electrolyte fuel cells, it is still necessary to investigate other ways to increase conductivity without affecting the dimensional stability.
PVA; fuel cell; HPW; silica; proton conducting membranes
