Novel fluoropolymer anion exchange membranes for alkaline direct methanol fuel cells

A series of novel fluoropolymer anion exchange membranes based on the copolymer of vinylbenzyl chloride, butyl methacrylate, and hexafluorobutyl methacrylate has been prepared. Fourier transform infrared (FT-IR) spectroscopy and elemental analysis techniques are used to study the chemical structure and chemical composition of the membranes. The water uptake, ion-exchange capacity (IEC), conductivity, methanol permeability, and chemical stability of the membranes are also determined. The membranes exhibit high anionic conductivity in deionized water at 65 C ranging from 3.86 x 10(-2) S cm(-1) to 4.36 x 10(-2) S cm(-1). The methanol permeability coefficients of the membranes are in the range of 4.21-5.80 x 10(-8) cm(2) s(-1) at 65 degrees C. The novel membranes also show good chemical and thermal stability. An open-circuit voltage of 0.7 V and a maximum power density of 53.2 mW cm(-2) of alkaline direct methanol fuel cell (ADMFC) with the membrane C, 1 M methanol, 1 M NaOH, and humidified oxygen are achieved at 65 degrees C. Therefore, these membranes have great potential for applications in fuel cell systems. (C) 2012 Elsevier Inc. All rights reserved.