Graphene oxide supramolecular hybrid hydrogels based on host−guest assembled electrostatic cross-linker

Abstract

Non-covalent self-assembly of multi-components is a promising strategy for constructing supramolecular hydrogels. However, it remains challenging to achieve the multi-responsiveness to external stimuli for supramolecular hydrogels through a low-molecular-weight hydrogelator. Herein, we report a host−guest complex as low-molecular-weight hydrogelator for constructing graphene oxide (GO)-based supramolecular hybrid hydrogels. A 1:2 homoternary complex (CB[8]·NMAH+2) was formed through host−guest encapsulation of two protonated naphthalen-2-ylmethanamine (NMAH+) molecules in cucurbit[8]uril (CB[8]) host and worked as dynamically assembled electrostatic cross-linker in the presence of GO. The resulted GO hydrogels showed shear-thinning, self-healing properties, and were stimuli-responsive to pH and competing guests. The proposed concept of “assembled electrostatic cross-linker” (AEC) would be extended to construct other novel stimuli-responsive supramolecular materials.