Improved antifouling properties of PVA hydrogel via an organic semiconductor graphitic carbon nitride catalyzed surface-initiated photo atom transfer radical polymerization

[Display omitted] •g-C3N4 catalyzed SI-photoATRP has not been developed in surface modification.•g-C3N4 is visible-light-responsive to reduce the side reaction.•g-C3N4 is easier to remove to solve the catalyst residues problem.•PVA-g-pMEDSAH performs excellent antifouling properties and biocompatibility. An innovative g-C3N4 catalyzed surface-initiated photo atom transfer radical polymerization (SI-photoATRP) has been developed to construct MEDSAH zwitterionic polymer brushes on PVA hydrogel surface. g-C3N4 catalyzed SI-photoATRP is temporal and spatial control. As a heterogeneous reaction system, it can solve the catalyst residues problem. After grafting with MEDSAH, surface chemical composition and morphology of PVA-g-pMEDSAH hydrogel confirmed that MEDSAH was successfully grafted onto PVA hydrogel. Thermal property of PVA-g-pMEDSAH hydrogel decreased and hydrophilicity increased. No statistically significant differences between PVA and PVA-g-pMEDSAH were observed on mechanical properties. Cytotoxicity in vitro of PVA-g-pMEDSAH hydrogel could be considered as no cytotoxicity for L929 and NDHF cells. The antifouling properties of PVA-g-pMEDSAH hydrogel were significantly improved due to the enhancement of the surface hydration and steric repulsion effects caused by pMEDSAH polymer brushes. In addition, g-C3N4 is easier to modify to enhance the photocatalyst property. Thus, the heterogeneous reaction system of g-C3N4 catalyzed SI-photoATRP has huge potential applied in biomaterials surface modification.