Colloidal phase behavior in a binary mixture

We present the observation of fluid‐solid phase transition in a close density matched system of charge stabilized polystyrene spheres suspended in a binary mixture. The microstructure and dynamics of crystallization are studied by Small Angle X‐ray Scattering (SAXS) and real space imaging in the confocal microscope. The reversible phase transitions are induced by using temperature as control parameter. The structure factor from SAXS can characterize the solid phase as fcc crystal; the radial distribution function of particles from confocal microscope can determine the particle pair potential in the dilute system in the qualitative manner. The colloids in a binary liquid mixture offer the opportunity to manipulate the particle interactions to understand the nature of weakly attractive systems.