High‐Performance pH‐Switchable Supramolecular Thermosets via Cation–π Interactions

Abstract Supramolecular chemistry has provided versatile and affordable solutions for the design of intelligent soft materials, but it cannot be applied in stiff materials. This paper describes a new concept for the design of high‐performance supramolecular thermosets by using the noncovalent cation–π interaction as cross‐linking. These supramolecular thermosets are a class of infusible and insoluble stiff polymers having excellent mechanical properties even at temperatures exceeding 300 °C. The cation–π interaction can be locally and reversibly installed and removed by aqueous treatments at high or low pH, respectively. Local manipulation of cross‐linking confers these thermosets with multiple stimuli‐responsive functions, such as recyclability, healability, adhesion, and nondestructive detection of cross‐linking and mechanical properties.