PVA/Agar Interpenetrating Network Hydrogel with Fast Healing, High Strength, Antifreeze, and Water Retention

Abstract Traditional self‐healing hydrogels have great application prospects in biological engineering because of their extremely high water content, but their durability cannot be easily guaranteed. Therefore, developing a rapid self‐healing hydrogel with long‐lasting water retention capacity is still a significant challenge. A high‐strength and fast self‐healing hydrogel with an interpenetrating double network based on polyvinyl alcohol/agar‐ethylene glycol (PVA/agar‐EG) is proposed. Polyvinyl alcohol (PVA) and agar are designed for the construction of the interpenetrating network. Furthermore, the introduction of a borate‐bonding dynamic action mode affords the hydrogel with extraordinary mechanical strength and rapid self‐healing. The addition of EG as a traveling solvent enables the sample to retain water and prevents freezing in harsh environments, including at high temperatures of 80 °C and extremely low temperatures of −40 °C. Additionally, owing to the intelligent remolding ability of the PVA/agar‐EG hydrogel, the material can be recycled to prolong the service life of the hydrogel. Overall, the PVA/agar‐EG hydrogel developed in this study can provide a new general strategy for the development of intelligent self‐healing devices, and hydrogels can be applied in complex environmental engineering.