The Polymer Society of Korea

Abstract

Recently, the stickers-and-spacers framework has been adopted to describe liquid-liquid phase separation (LLPS) of biopolymers such as proteins and nucleic acids. In this work, we introduce peptide-inspired sticker-spacer polymers consisting of arginine-like guanidinium (G) stickers and lysine-like ammonium (A) spacers. When electrostatic repulsion is attenuated under high ionic strength, the sticker-spacer polymer undergoes LLPS in aqueous solutions, driven by attractive pi-pi interactions between G stickers. This LLPS behavior exhibits an upper critical solution temperature (UCST) and is highly programmable by varying salt concentration and sticker fraction. These results indicate that the sticker-sticker interactions of G-containing polymers are readily tunable by adjusting ionic strength and sticker valence, suggesting that associative polymers with G stickers are promising building blocks for designing stimuli-responsive polymeric materials in complex aqueous fluids.