High strength PVA/poly (AACA-co-DMC) hydrogels self-healing in both alkali and acid solutions

It is still challenging to prepare high strength hydrogels which can self-heal in both alkali and acid solutions. In this work, 6-acrylamidohexanoic acid (AACA) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (DMC) monomers were copolymerized in a mixture solution of polyvinyl alcohol (PVA) and borax to prepare high strength and pH responsive hydrogel. Compared with borax cross-linked PVA gel, this hydrogel exhibits better mechanical properties owing to multi-physical interactions like electrostatic interactions and hydrogen bonds. Due to the presence of noncovalent interactions the hydrogel exhibits different degrees of self-healing ability in acid and alkali at the same time. Furthermore, the conductivity of the hydrogel can be significantly change with slight deformation, which can be used to monitor the body movement like swallow and finger bending.