Adhesive and self-healing soft gel based on metal-coordinated imidazole-containing polyaspartamide

A supramolecular gel formed by coordination of Ni(II) with poly(2-hydroxyethyl-co-1-(3-imidazolyl)propyl aspartamide) (PHEA-API) is reported. Novel polyaspartamide copolymers, PHEA-API, were prepared from polysuccinimide, which is the thermal polycondensation product of aspartic acid, via a successive ring-opening reaction using 1-(3-aminopropyl imidazole) (API) and ethanolamine (EA). Ni(II)-mediated gels, cross-linked by metal–ligand coordination, showed self-healing viscoelastic behavior in rheological analysis, which was also well reflected in high bulk adhesion strength on various different substrates. The approach described here results in a promising self-healing adhesive hydrogel with potential for a variety of industrial and biomedical applications including tissue adhesive, sealant, and smart drug delivery systems.