An AIE-active supramolecular cross-linked polymer gel based on multiple orthogonal non-covalent interactions with stimulus-responsive properties

Abstract

Owing to their abundant responsive moieties, supramolecular gels constructed through multiple non-covalent interactions serve as an indispensable platform for the fabrication of smart soft materials. In this work, we employed multiple orthogonal non-covalent interactions to construct a novel multi-stimuli-responsive supramolecular cross-linked polymer gel with AIE activity. Specifically, we designed and synthesized a tetraphenylene (TPE)-embedded asymmetric crown ether macrocycle BCE, along with a guest polymer G1 bearing a 2-ureido-4[1H]-pyrimidinone (UPy) motif. The host BCE and the guest G1 co-assemble into a supramolecular cross-linked polymer gel BCE⊃G1 based on host–guest interactions and the strong dimerization of quadruple hydrogen bonds. By exploiting the selective binding of Na⁺ to the smaller-sized crown ether cavity of BCE, the fluorescence intensity of the BCE⊃G1 polymer solution can be effectively regulated. This supramolecular gel not only demonstrates reversible expansion–contraction behavior but also exhibits sensitive responsiveness to external stimuli, underscoring its potential as an ideal platform for the development of intelligent stimulus-responsive nanomaterials.