Understanding Binary Interactions and Aging Effects in Catalyst Layer Inks for Controlled Manufacturing

The effect of perfluorosulfonated ionomer loading in carbon-based colloidal inks is investigated under static and dynamic operating conditions. The results show that both the solvent-type and polymer loading play a role in ink stability, aggregation, and aging. Dynamic light scattering and shear and creep rheological experiments show that the addition of a polymer to carbon inks can act as a stabilizing agent which increases steric repulsion and decreases the inks overall viscosity. As the polymer loading is increased above 30wt% a decrease of approximately 30 MPa-1 in compliance is observed. A decrease in compliance at high polymer loading suggests weak interactions between the underlying carbon materials and indicates that a critical polymer loadings may exist for different shear processing routes.