Phenomenological Description of Phase Separation

Phenomenological Description of Phase Separation. Phase separation due to thermal gelation, evaporation of solvent and addition of nonsolvent can be illustrated with the aid of the phase diagram of a polymer solution. 

The points P and S represent the pure components, polymer and solvent respectively, and points on the line P-S describe mixtures of these two components. If a homogeneous mixture of the composition Xp at a temperature T), 

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