THERMODYNAMICS OF PHASE SEPARATION IN MIXTURES OF OPPOSITELY CHARGED POLYELECTROLYTES.

Complex coacervation is seen as a process whereby charge interactions lead to the formation of a new component or, in more thermodynamic terms, a standard state change. The complex then behaves as a single component obeying the basic Flory-Huggins polymer binary mixture phase separation rules. While this may be a seemingly trivial answer to a complex problem, the implications for further investigation are quite important. They center, however, not on the coacervate phase as such, though this too has interesting properties. More directly, the molecular weight selectivity, thepartitioning of molecules in heterogeneous mixtures and the possible enhancement of specific structure formation in the paired aggregate suggest that the coacervation process can produce new properties for combinations of unlike polymers for any situations where a small non-specific exergonic polymer-polymer interaction exists so long as several interaction regions are involved.