Design of a Self-Healing and Highly Adhesive Hydrogel via Borate Ester and Fe3+-Catechol Coordination

Md Shamimun Fuad, Xiufang Zhu, Jie Cheng, Jingyang Zhao

Abstract: This study presents the development of a highly adhesive and self-healing hydrogel (HASHH) through a synergistic integration of polyvinyl alcohol (PVA), acrylic acid (AA), borax, ferric ions (Fe??), and polydopamine (PDA). The hydrogel network is formed via free-radical polymerization and reinforced by reversible dynamic interactions including borate ester bonds and Fe³⁺-catechol coordination. Characterization using SEM, FTIR, TGA, tensile testing, and swelling analysis confirms enhanced mechanical properties, thermal stability, and self-healing efficiency exceeding 95% within 24 hours. PDA incorporation significantly improves adhesion, with an adhesion strength of 0.084 MPa on aluminum substrates. The findings suggest HASHH is a promising candidate for biomedical applications such as wound dressings, tissue adhesives, and wearable sensors.

Keywords: self-healing hydrogel, polydopamine, borate ester, Fe³⁺ coordination, tissue adhesive