The Polymer Society of Korea

Abstract

Coacervation refers to the phase separation of protein or polyelectrolyte solutions into polymer-rich and polymer-dilute phases due to attractive interactions between polymer species. Specifically, simple coacervation involves a single polymer species, whereas complex coacervation occurs between oppositely charged polyelectrolytes. In simple coacervation, salt addition can either increase (salting-in) or decrease (salting-out) polymer solubility depending on the salt type. In complex coacervation, on the other hand, salt screens electrostatic interactions and can lead to the dissociation of polyelectrolyte complexes. Moreover, salt ions can either decrease or increase salt resistance of complexes by acting as preferential counterions or co-ions. In this study, we explore the potential of polyelectrolyte coacervate membranes for selective ion separation by utilizing the ion-specific phase behavior of coacervates. This approach is distinct from conventional ion separation mechanism such as Donnan exclusion, size exclusion, or dielectric exclusion. Our findings will enhance the understanding of the ion-specific effects on coacervation and can hold promise for advancing ion separation technologies.