Structure, properties and proton conductivity of Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2 nanocomposite membranes

In this report are presented the preparation and the characterization of six nanocomposite membranes of formula {Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2}{Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2} with ψTiO2ψTiO2 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]ψTiO2}{Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2} membranes was studied. The water uptake (WU) value of materials was lower than that of pristine Nafion and was correlated with ψTiO2ψTiO2. 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 μ-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]ψTiO2}{Nafion/[(TiO2)⋅(WO3)0.148]ψTiO2} nanocomposite membrane, with ψTiO2=1.616ψTiO2=1.616, at 135 °C, is 5.0 × 10−2 S cm−1, while its stability range of conductivity (SRC) extends up to 135 °C.