Biopolymer-based electrolyte membranes from chitosan incorporated with montmorillonite-crosslinked GPTMS for direct methanol fuel cells
A composite membrane was fabricated from biopolymer chitosan and montmorillonite (MMT) filler as an alternative membrane electrolyte for direct methanol fuel cell (DMFC) application. To first improve the organic–inorganic interfacial morphology, the pristine MMT was pre-treated using 3-glicidoxy propyltrimethoxysilane (GPTMS) surface modifier to produce organophilic MMT (O-MMT). The GPTMS modified MMT was mixed with chitosan in acetic acid solution and cast into membranes. SEM images and FTIR analysis showed that the O-MMT was successfully incorporated into the chitosan polymer matrix. Water and methanol uptake of the Ch/O-MMT composite membranes decreased with increasing O-MMT loadings, but the ion exchange capacity (IEC) value increased. The Ch/O-MMT with 5 wt% O-MMT loading exhibited the best methanol permeability and proton conductivity characteristics among the other Ch/O-MMT membranes, which were 3.03 × 10−7 cm2 s−1 and 4.66 mS cm−1, respectively. All the results obtained from this study can be used to conclude that the chitosan membrane with O-MMT filler is a promising high performance PEM candidate for DMFC application.