Abstract
Effect of solute sizes on their miscibility in the freeze-concentrated phase among ice crystals was studied using poly(vinylpyrrolidone) (PVP), Ficoll, sucrose, and dextran as models. Thermal analysis of the frozen solutions containing various concentration ratios of higher molecular weight polymers showed two transitions (glass transition temperatures of maximally freeze-concentrated solutes: T_g's) near the individual polymer T_g's at wide concentration ratios, indicating separation into different phases. Smaller polymer combinations showed a single transition of the solute-mixture concentrated phase that moved between the intrinsic T_g's depending on the concentration ratios. The polymer size and concentration ratios, as well as the structure and co-solute compositions, are important factor that determine their miscibility in frozen solutions.
