Preparation conditions of inorganic–organic hybrid membranes synthesized from Epoxycyclohexylethyltrimethoxysilane and 1-hydroxyethane-1, 1-diphosphonic acid

Proton conductive inorganic–organic hybrid membranes were synthesized from Epoxycyclohexylethyltrimethoxysilane (EHTMS) and 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) by the sol–gel method. In this paper, the effect of gel temperature, membrane-forming temperature and Si/P on hybrid membranes performance were discussed. FT-IR studies revealed the phosphonic acid was chemically bonded to the siloxane network. When the membrane-forming temperature is 150 °C, thermal analysis including TG and DTG confirmed that the hybrid membranes were thermally stability up to 250 °C and SEM images showed that the membranes surface smooth and dense, eliminating the phase separation phenomenon. The hybrid membranes with a molar ratio of Si/P = 6/1 possess better thermal stability and preferable flexibility.