Structural study on inorganic/organic hybrid composite membranes

New composite materials consisting of phosphosilicate (P(2)O(5)-SiO(2)), phosphotungstic acid (PWA), 3-mercaptopropyltrimethoxysilane (MPTS) and glutaraldehyde (GL) were prepared, and a high proton conductivity of 10(-2) S cm(-1) was observed at room temperature. By incorporating 3-mercaptopropyltrimethoxysilane (MPTS) and glutaraldehyde (GL) in to the P(2)O(5)-SiO(2)-PWA inorganic matrix, the composites showed high proton conductivity in the range of 10(-2) -10(-1) S cm(-1) at 120 degrees C. The structural formation was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and morphological analysis. The thermal properties were investigated by thermogravimetry (TG) and differential thermal analysis (DTA). A new inorganic-organic composite membrane was successfully prepared by a sol-gel process through hydrolysis and condensation of MPTS and tetraethoxysilane (TEOS). These P(2)O(5)-SiO(2)-PWA-MPTS, P(2)O(5)-SiO(2)-PWA-GL and P(2)O(5)-SiO(2)-PWA-MPTS-GL hybrid composite membranes showed high proton conductivities as a function of temperature. Moreover, they were thermally stable in air up to 250 and 300 degrees C due to the presence of a tolerant inorganic SiO(2) framework in the matrix.