Multi-stimuli responsive supramolecular hydrogels based on Fe3+ and diblock copolymer micelle complexation

Abstract

Stimuli-triggered degradable hydrogels have found broad applications in controlled release of drugs, fragrances, flavourings and fertilizers. Recently, multi-stimuli responsive micelle-based hydrogels have gained focus, since they could respond to a combination of external stimuli. Herein, a multi-stimuli responsive supramolecular hydrogel with great potential for biomedical application was prepared, which was composed of the micelle-forming diblock copolymer poly[(N-isopropylacrylamide-co-2-nitrobenzyl acrylate)-block-(N,N-dimethylacrylamide-co-acrylic acid)] (P(NIPAM-co-NBA)-b-P(DMA-co-AA)), and physically cross-linked by supramolecular complexation between AA groups and ferric ions (Fe³⁺), exhibiting gel–sol transition caused by UV irradiation, multidentate ligands (EDTA) and redox agents (Na₂S₂O₄).