Structure, properties and proton conductivity of Nafion/[(TiO2)center dot(WO3)(0.148)](psi TiO2) nanocomposite membranes

In this report are presented the preparation and the characterization of six nanocomposite membranes of formula {Nafion/[(TiO2).(WO3)0.148]yTiO2)} with yTiO2 in the range 0-2.988. These materials are based on Nafion and [(TiO2).(WO3)0.148] nanofiller. The effect of [(TiO2).(WO3)0.148] nanopowders on the structural, thermal, mechanical and electrical properties of {Nafion/[(TiO2).(WO3)0.148]yTiO2} membranes was studied. The water uptake (WU) value of materials was lower than that of pristine Nafion and was correlated with yTiO2. The thermal transitions were investigated by modulated differential scanning calorimetry (MDSC). The mechanical parameters and relaxation processes on temperature were studied by dynamical mechanical analyses (DMA). The FT-IR ATR and mu-Raman vibrational investigations allowed to determine the structure of the hydrophobic polytetrafluoroethylene (PTFE) domains of Nafion and the interactions Nafion-[(TiO2).(WO3)0.148] and Nafion-[H2O] in bulk materials. The analysis of complex conductivity plots were evaluated in the 10-2 Hz-10 MHz and 5-155°C regions. Results indicated that the conductivity of {Nafion/[(TiO2).(WO3)0.148]yTiO2} nanocomposite membrane, with yTiO2 = 1.616, at 135°C, is 5.0 x 10-2 S/cm, while its stability range of conductivity (SRC) extends up to 135°C