Nanocomposite polymer electrolytes membranes based on Poly(vinylphosphonic acid)/SiO2

Proton conducting polymer electrolytes bearing phosphonic acid units are very promising due to their high conductivity, thermal and chemical stability. In the present work, proton conducting nanocomposite electrolytes containing poly(vinylphosphonic acid) (PVPA) and SiO2 were prepared by two different methods. The interaction existed between PVPA and SiO2 was confirmed by FT-IR spectroscopy. The surface roughness of the nanocomposites was studied using AFM. Thermogravimetric analysis revealed that the samples were thermally stable up to 200 degrees C. The glass transition temperature (Tg) of the materials were determined using DSC. In the anhydrous state, the proton conductivity of PVPA(10)SiO2 (in situ) was found to be 0,009 (Scm(-1)) at 120 degrees C. The proton conductivity of PVPA(10)SiO2 increased to 0.08 (Scm(-1)) at 50 % relative humidity. The SiO2 nanoparticles in the composite membranes improved the thermal properties and increased the proton conductivity.