Electrical Spectroscopy Studies of Organic/Inorganic Nano Composites

The electrical conductivity studies of chemically crosslinked nano composite membranes consisting of poly (vinyl alcohol) (PVA) and phosphomolybdic acid (PMA) with different blending composition and crosslinking density has been conducted over a wide frequency regime. The conductivity of the systems has been studied within the temperature range 25 oC ø T oe 100 oC for the hydrated membranes. The proton conductivity of the membranes was generally of the order of 10-3 S/cm. The conductivity of these membranes shows a temperature dependence of Arrhenius type. The activation energies for the membranes were calculated from the conductivity measurements. Both the pristine and hydrated membranes were also characterized by X-Ray diffraction studies to observe the effects of blending and hydration on the crystallinity of the composite membranes. The membranes showed comparable proton conductivity and better resistance to methanol permeability than that of Nafion 112 under the same measurement conditions. These properties make them good candidates as polymer electrolyte membranes for direct methanol fuel cell application.