Synthesis of a self-healable and pH responsive hydrogel based on an ionic polymer/clay nanocomposite

This investigation reports the preparation of a pH responsive self-healing nanocomposite hydrogel based on the in situ polymerization of 2-(acryloyloxy)ethyl trimethylammonium chloride and acrylic acid using N,N′-methylenebisacrylamide as a crosslinker and ammonium persulfate (APS) as a thermal initiator in the presence of soluble starch and organically modified montmorillonite (OMMT). The hydrogel was characterized using FTIR, SEM and TEM analyses. The influence of different parameters in swelling was investigated. The self-healing ability of the hydrogel was measured in different pH media and it was observed that it can show self-healing ability in physiological pH (pH = 7.4), in acidic pH (pH = 1.2) and in saline solution. This developed hydrogel showed excellent swelling ratio, mechanical strength, and elasticity. The hydrogel exhibited modulus values (G′, G′′) in the range of 10² Pa.