Marc Radu, Tanja Schilling
Suspensions of colloidal hard particles are a well established model system to study fundamental questions of statistical mechanics experimentally and theoretically. Their popularity as a model system is partly due to the assumption that solvent effects on phase transition kinetics can easily be factored out -- at least if one considers processes that are very slow compared to diffusive time-scales. In particular, crystal nucleation rates for hard sphere suspensions are often compared in units of a "typical" diffusion time. Here, we present a study on the crystallization process in supersaturated suspensions of hard spheres, taking into account the solvent viscosity via hybrid dynamics simulations. We show that, although the induction times are long compared to the diffusion time, crystal nucleation rates still depend strongly on the solvent viscosity. We do not observe any differences in the sizes, shapes or structures of the nuclei that are formed. The effect is purely kinetic. As crystal nucleation kinetics are influenced non-trivially by hydrodynamic interactions, colloids might not be as ideal a model system to study phase transitions as has been assumed up to now.
View original:
http://arxiv.org/abs/1301.5592
No comments:
Post a Comment