A Simulation Study on Dynamic Behavior of Equilibrium Polymer-Linked Colloidal Gels

Colloids with limited valence such as patchy particles can form equilibrium gels that are thermodynamically stable. Polymer-linked colloidal gels are promising candidates due to the possibility to tune valence using the macroscopically controllable ratio of linkers to colloids. Still, an understanding of the dynamics of such networks, and how they relate other systems such patchy colloids, is lacking. Using simulations of a coarse-grained model, we show that linked-colloidal networks exhibit dynamic hallmarks of viscoelastic equilibrium gels. Our results demonstrate that network bond persistence time controls structural relaxation. We also find the re-entrant structural and dynamic behavior as a function of linker concentration, centered at the stoichiometric ratio. Increasing or decreasing linker concentration from the stoichiometric ratio results in reduced network connectivity and shorter structural relaxation times. These results provide fundamental insights and suggest new macroscopic strategies for tuning the network connectivity and the dynamical response in colloidal networks.