By measuring the orientation of colloidal doublets suspended in water under the opposing alignment forces of gravity and electrophoresis, we observed tangential forces between nontouching particles. We found a new phenomenon of time-dependent switching between “slipping” (no tangential force) and “sticking” (tangential forces producing rigid-body behavior of the doublet) for heterodoublets of silica/polystyrene. Tangential forces between particle surfaces across a fluid gap and their transient nature are important to the dynamics of colloidal suspensions and the evolution of floc morphology.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)