Characterization of Low Cost Ion Conducting Poly(AAc-co-DMAPMA) Membrane for Fuel Cell Application

Abstract

Poly(AAc-co-DMAPMA) membrane (PADMA) is synthesized by free radical aqueous copolymerization of acrylic acid (AAc) and N-3-[dimethylamino)propyl]-methacrylamide (DMAPMA) to check its stability and conductivity. The hydrogel membrane characterized physically to study morphology by SEM, thermal stability by TGA and mechanical stability by measuring compressive strength and ionic conductivity by electrochemical impedance spectroscopy in alkaline as well as in acidic environment at different temperatures. The compression modulus of the hydrogel membrane is 24 kPa at pH = 1.0 and 16 kPa at pH = 7.0, and stable (no fracture) till 72% deformation. The PADMA hydrogel membrane ionic conductivity increased with the increase in temperature and structurally stable up to 190°C. Improvement in ionic conductivity is observed after the heat treatment of the membrane. Compared with ionic conductivity of Nafion? (SE512), the PADMA membrane found to be inferior. However, the PADMA hydrogel membrane conductivity was greater (~1 × 10 -4 S/cm) at low and high pH compared with neutral pH (~1 × 10 -5 S/cm) indicating the possibility of using the membrane as either a proton and hydroxyl ion conductor.