LCST behavior controlled by size-matching selectivity from low molecular weight monomer systems

Despite increasing attention being focused on traditional polymer-based LCST systems, only a limited number of LCST systems induced by small molecules have been investigated. In this paper, we developed a series of new thermo-responsive small molecules with crown ether units as the thermo-sensitive cores. The diversity in the crown ether structures fully demonstrates the differences in water solubility and LCST properties. Due to the competition between the supramolecular recognition process induced by the size-matching selectivity and the salting-out effect caused by cation-water-crown ether solvation, controllable and programmable thermo-responsive properties are realized.