Improving the ionic conductivity in nanostructured membranes based on poly(vinyl alcohol) (PVA), chitosan (CS), phosphoric acid (H3PO4), and niobium oxide (Nb2O5)

Nanostructured membranes based on poly(vinyl alcohol) (PVA) and chitosan (CS) weight ratio of PVA:CS (80:20), mixed with 40% phosphoric acid (H 3 PO 4 ) and finally doped with nanoporous niobium oxide (Nb 2 O 5 ) at different concentrations, were prepared by solution casting method. The ionic transport, structural, and thermal properties were studied by different techniques. Thermal analysis shows the glass transition temperature between 8 and 18 °C with a melting point around 160 °C. Impedance spectroscopy shows a maximum conductivity value of 4.67 × 10 −2 Scm −1 at 130 °C for the sample with 6% of Nb 2 O 5 , improving the ionic conductivity with respect to that of PVA:CS + 40% H 3 PO 4 concentrations.