Implantation of Nafion® ionomer into polyvinyl alcohol/chitosan composites to form novel proton-conducting membranes for direct methanol fuel cells

A series of cost-effective, proton-conducting composite membranes, comprising of Nafion® ionomer, chitosan (CS), and polyvinyl alcohol (PVA), is successfully prepared. By taking advantage of the strong electrostatic interactions between Nafion® ionomer and CS component, Nafion ionomer is effectively implanted into the PVA/CS composite membranes, and improves proton conductivity of the PVA/CS composite membranes. Furthermore, this effect dramatically depends on the composition ratio of PVA/CS, and the optimum conductivity is obtained at the PVA/CS ratio of 1:1. The developed composite membranes exhibit much lower methanol permeability compared with the widely used Nafion® membrane, indicating that these novel membranes have great potential for direct methanol fuel cells (DMFCs).