Aggregation of ionomer and carbon blacks during MEA preparation: model to characterize particle size and catalyst accessibility

摘要

Aggregates form when ionomers such as Nafion are mixed with small particles. The formation of these aggregates is driven by particle surface area and cohesive energy between ionomer fluorocarbon side chains. A model is suggested for relating the size of aggregates to basic properties of the ionomer and particles. The model is applied to inks of Nafion and the platinized carbon black, Vulcan XC-72. Design notions for varying the properties of MEA inks are presented.