Aqueous Multi‐Phase Systems From Polyacrylamides and Poly(ethylene glycol)

ABSTRACT Aqueous two‐phase systems (ATPSs) have attracted considerable attention as environmentally friendly multicompartment systems used for molecular separation and microgel templating that eliminate the need for organic solvents. The limited variety of polymers employed in ATPS applications, however, constrains their potential utility. This study systematically investigates binary combinations of poly(ethylene glycol), poly(acrylamide), and poly( N ‐acryloylmorpholine) to identify novel ATPSs. The three binary combinations spontaneously form ATPSs, and phase diagrams for all two‐phase systems are described. Furthermore, the studied ATPSs can be dispersed to form water‐in‐water (w/w) emulsions via nanoparticle stabilization. Fluorescently labeled polymers enable visualization of polymer distribution within the emulsion phases. Extension to ternary polymer systems was also investigated, revealing unprecedented ATPSs. Also for the ternary system, polymer behavior in stabilized emulsions was characterized using fluorescent labeling techniques. These findings expand the repertoire of polymer combinations available for aqueous multiphasic systems and provide a foundation for future partitioning studies aimed at developing novel extraction methodologies as well as microgel templates.