  We study the thermodynamics of binary mixtures wherein the volume fraction of
the minority component is less than the amount required to form a flat
interface. Based on an explicit microscopic mean field theory, we show that the
surface tension dominated equilibrium phase of a polymer mixture forms a single
macroscopic droplet. A combination of elastic interactions that renormalize the
surface tension, and arrests phase separation for a gel-polymer mixture,
stabilize a micro-droplet phase. We compute the droplet size as a function of
the interfacial tension, Flory parameter, and elastic moduli of the gel. Our
results illustrate the importance of the rheological properties of the solvent
in dictating the thermodynamic phase behavior of biopolymers undergoing
liquid-liquid phase separation.
