Control of nanoparticle dispersion in SPAES/SiO₂ composite proton conductors and its influence on DMFC membrane performance

A novel approach for effectively dispersing SiO₂ nanoparticles in a sulfonated poly(arylene ether sulfone) ionomer (SPAES) matrix has been demonstrated. It is based on the application of wet-type milling process. Compared to a conventional mixing process such as sonication, wet-type milling allowed noticeable improvements in SiO₂ nanoparticle dispersion, owing to the intensive impact of collisions between milling beads and nanoparticles. In terms of nanoparticle dispersion, the influence of wet-type milling on the direct methanol fuel cells (DMFC) membrane performance such as proton conductivity, methanol permeability, and selectivity was examined and compared with sonication process. This study underlines that nanoparticle dispersion in the composite membranes is crucial in determining DMFC membrane performance and can be substantially improved by employing a novel mixing process, i.e. wet-type milling.