Rich Phase Behaviors of Colloids with Realistic Pair Potentials

Abstract

Colloids have been used as models to research phase behaviors of atoms and molecules. Although hard spheres undergo crystallization and melting analogous to atoms, so chosen for the study of phase transition, they meet drawbacks in implementing essential properties of atoms and molecules with attractive potentials. In this study, depletion attraction provides realistic pair potentials between colloids, and their rich phase behaviors are studied. The interparticle interactions are elaborately controlled experimentally, from which fluids, crystals, and glasses are produced. Phase boundary between the fluids and crystals is defined with the potential well-depth, whereas the slope better describes that between the crystals and glasses. The crystal growth is diffusion-limited. Ostwald ripening for a large Laplace pressure gradient decreases the number of crystallites. The crystal shapes are selected to either polygons or dendrites, which rely on maintaining the concentration gradient.