Ionic-Group Dependence of Polyelectrolyte Coacervate Phase Behavior

A complex coacervate is the polymer-rich phase resulting from liquid–liquid phase separation induced by two oppositely charged polyelectrolytes in an aqueous solution, which shows the considerable potential of functional materials and the substantial role of biological processes. In this study, the phase behavior of complex coacervates for differently charged moieties is investigated using well-defined polyether-based polyelectrolytes functionalized with ammonium, guanidinium, sulfonate, and carboxylate groups. Turbidity measurement and thermogravimetric analysis provide the stability and phase diagram of the complex coacervates, indicating a significant role of the pair of charged groups. In stark contrast to ammonium-based coacervates, guanidinium-based coacervates show considerable stability upon the addition of salt and enhanced dehydration with increasing salt at low salt concentrat…