In 'low solid-content' colloidal dispersions such as that of catalyst inks, hydrodynamic interactions play a crucial role in the evolution of the microstructure. However, explicit representation of the surrounding solvent is too computationally expensive to model in the mesoscale. In order to elucidate the effect of hydrodynamics on the co-aggregation of Pt/C and ionomer, we opted for an implicit solvent approach that aims to capture solvent dynamics as a function of pair wise dissipative inter-particle interactions.