Crystallization kinetics of a colloid-polymer system with depletion interaction

Compared to systems with only a steric interaction, a colloidal system with an attractive interaction, caused by addition of a polymer, exhibits a richer set of phases. Richer because more phases are possible; for example, one can actually see the coexistence of liquid, gas and crystal phases in equilibrium. In this thesis, we studied the crystallization of colloid particles in a colloid-polymer system. To understand how crystals nucleate within different phases, the samples investigated were in the three-phase region of the colloid-polymer phase diagram. Experiments were carried out in a microgravity environment on board the International Space Station (ISS). The samples were photographed as they crystallized and captured images were sent to Earth. Python scripts were developed to analyze data from the images. One key observation similar to that observed in a hard-sphere system was the formation of dendrites in one of the samples suggesting diffusion-limited growth.