A novel photo-regulated self-healing hydrogel based on hollow SiO2@g-C3N4@TiO2 and PVA

Self-healing hydrogels have the ability to repair themselves at the incision after being damaged and can return to their original state of morphology and performance. However, constructing a hydrogel with superior mechanical strength and tensile properties after self-healing remains a challenge. In this work, using polyvinyl alcohol, borax, chitosan, and a type of SiO2@g-C3N4@TiO2 nanoparticles as raw materials, a novel photo-regulated self-healing hydrogel was developed using a freezing–thawing method, which could achieve a synchronous increase in Young's modulus and tensile strength under visible light irradiation during the self-healing process. In addition, the doping of the SiO2@g-C3N4@TiO2 nanoparticles improved the self-healing performance of the PVA-based hydrogels. With the addition of a trace amount of SiO2@g-C3N4@TiO2 nanoparticles, the self-healing efficiency of the hydrogel increased from 26.67% to 45.67% in darkness and from 41.33% to 65.67% under visible light irradiation.