The Impotence of Non-Brownian Particles on the Gel Transition of Colloidal Suspensions

摘要

The ability to predict transitions in the microstructure of mixed colloidal suspensions is of extreme interest and importance. The data presented here is specific to the case of battery electrode slurries whereby the carbon additive is reported to form strong colloidal gels. Using rheology, we have determined the effect of mixed particle systems on the critical gel transition ϕgel. More specifically, we show that the introduction of a high volume fraction of large non-Brownian particles has little to no effect on ϕgel. Although ϕgel is unchanged, the larger particles do change the shape of the linear viscoelasticity and the nonlinear yielding behavior. There are interesting similarities to the nonlinear behavior of the colloidal gels with trends observed for colloidal glasses. A comparison of experimental data and the prediction from theory shows that the equation presented by Poon et al. is able to quantitatively predict the transition from a fluid state to a gel state.