Ion Pair Recognition Based Supramolecular Polymer Showing Rapid and Reversible Sol-Gel Transition through van der Waals Interactions

Ion pair receptors have shown potential in controllable recognition of cations and anions simultaneously, which has made a vital contribution to various research fields. Herein, rationally designed ion pairs were integrated into a calix[4]pyrrole skeleton, resulting in the formation of an ion pair recognition based linear supramolecular polymer. The effect of simultaneous host-guest and cation-πinteractions between carboxylate-functionalized calix[4]pyrrole and cetyltrimethylammonium was investigated by nuclear magnetic resonance spectroscopy, viscosity measurements, scanning electron microscopy, and differential scanning calorimetry. The resulting supramolecular polymer was found to show temperature-induced rapid and reversible sol-gel transition through van der Waals interactions of cetyl units.