Covalent Cross-Linked Polymer Gels with Reversible Sol-Gel Transition and Self-Healing Properties

A strategy of constructing novel reversible polymer gels based on dynamic covalent chemistry. Covalent and reversible noncovalent interactions are two basic cross-linking forces to form three- dimensional networks in polymer gels. The networks based on covalent bonds in chemical gels are stable under ambient conditions owing to their robust and irreversible natures of the covalent bonds. Dynamic covalent chemistry offers an appealing prospect of constructing such materials. The chemical gel possesses self-healing property based on the reversible breaking and regenerating of acylhydrazone bonds. The dynamic polymer gels formed as well in other solvents such as ethanol, DMSO and CH 2Cl2. These gels were covalent cross-linked and revealed typical properties of chemical gels. The present discovery indicates that dynamic polymer gels may have a broad application as smart soft materials.