Nakajima and Sato (1972) have discussed the complex coacervation of sulfated polyvinyl alcohol) and an aminoacetalysed polyvinyl alcohol). The three component system of the polymer salt, water and sodium bromide was investigated. The results are interpreted according to a theoretical equation for the free energy of mixing, taking into account the entropy and enthalpy contributions.
In a second paper, Sato and Nakajima (1974a) reported on the conditions for complex coacervation of the two polymers by relating the effects of charge density on phase separation. Conditions for coacervation were discussed as a function of chain length, interaction between polymer and water, the temperature, the electrostatic interaction and the number of charges on the polyelectrolyte chain. Subsequently, the authors, Sato and Nakajima (1974b,c), discussed the conditions for the formation of coacérvate droplets as a function of charge density and polymer concentration. Furthermore, they indicated that the concentration of the coacérvate phase at 25 °C decreased and the concentration of the equilibrium liquid phase increased with increasing polymer concentration. The reduced viscosity of aqueous solutions of both polymers increased with decreasing polymer concentrations. The volume and polymer fraction of the coacervate phase containing the two polymers passed through a maximum value with increasing polymer concentration.
Okihana and Nakajima (1976) found that a 1:1 complex formed upon mixing the ratio of two polymers. The concentration of polymers in the coacervate and equilibrium liquid depended upon the initial polymer concentration. Coacervation of the 1:1 complex was suppressed by the addition of salts owing to a change in chain conformation.
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