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 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 polymer BCE⊃G1 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.