Supramolecular control over thermo-responsive systems with lower critical solution temperature behavior

Abstract

Lower critical solution temperature (LCST) is the critical temperature below which the solution is miscible for all compositions and above which the solution becomes a suspension. The study of LCST properties has become a central research topic due to its profound impact on the applications of stimuli-responsive materials. Inspired by the marriage between materials science and supramolecular chemistry, the introduction of supramolecular pairs and interactions into polymeric LCST systems is increasingly practiced. Especially, supramolecular interactions provide precise control over LCST behavior in both water and organic solvents. Furthermore, supramolecular interactions not only control or adjust LCST behavior (supramolecular interaction controlled LCST), but also induce LCST phase behavior in species lack of thermo-sensitive properties (supramolecular interaction induced LCST). In this review, we summarize the applications of supramolecular interactions in LCST systems. By examining the relationship between supramolecular interactions and LCST changes, we further discuss the differences between supramolecular interaction controlled LCST and supramolecular interaction induced LCST. We hope this review will give our readers a snapshot on how the supramolecular interactions influence the LCST behavior in various systems, and benefit them with different applications.