On the Long-Term Stability of Colloidal Gels

Executive Summary

Building on preliminary results obtained at the end of our first three-year project, we have confirmed that curved menisci of whatever origin limit the life time of depletion-induced colloidal gels. Optical imaging reveals that rapid structural collapse is always initiated at these curved interfaces. Having shown that hydrodynamics is crucial for simulating realistic collapse in our previous project, we have now implemented the lattice-Boltzmann method for simulating gels, in which far-field flows are fully accounted for. Exploration of hydrodynamic interactions is now possible on desktop graphics processing unit (GPU) machines. Results to date show that such interactions are crucial for the aging of the gel structure before large-scale collapse, and speed up such collapse by generating back flows.