Lower Critical Solution Temperature Active Supramolecular π-Systems for Smart Applications

Stimuli-responsive supramolecular systems have emerged as an essential requirement for a wide range of smart applications in material sciences and biology. Among various responses, thermal response is a common functional characteristic of macromolecular and supramolecular systems. For example, polyacrylamides and their variants are known to exhibit a phenomenon called lower critical solution temperature (LCST) under aqueous conditions, which is a heat-induced phase change from a transparent to opaque state. Similarly, numerous amphiphilic supramolecular systems are known to exhibit LCST properties. π-Conjugated molecules are emerging as preferred building blocks for the construction of LCST active supramolecular materials owing to their inherent electronic and optical properties, which are sensitive to temperature variations. A variety of amphiphilic π-systems have been reported for the creation of dynamic and adaptive LCST materials, and a combined analysis of such materials is important for further developments. In this minireview, we describe how researchers have exploited the LCST property of supramolecular π-systems for various smart applications, such as smart windows and nanothermometers, and discuss their future potential and challenges.