Phase-Field Modeling of Colloid-Polymer Mixtures in Microgravity*

We present a theoretical model of colloid-polymer mixtures in a microgravity environment. Studying such mixtures gives us valuable insight into phase transition processes--insight that can be applied to various materials on earth. The addition of polymer to a colloidal suspension induces weakly attractive forces between the colloids and leads to a three-phase coexistence region, wherein a "liquid" phase coexists with a low-density gas phase and a high-density crystal phase. We construct, analyze and numerically simulate a phase-field model for phase separation in colloid-polymer mixtures. The results of our model simulations will be compared against experiments performed on the International Space Station, using image data available on the NASA Physical Sciences Informatics system.