Near-infrared light-responsive shape memory hydrogels with remolding and excellent mechanical performance

In recent years, intelligent shape memory hydrogels (SMHs) have received extensive attention. However, due to the limitations of their poor mechanical properties and the single functionality of soft materials, the requirements of shape memory hydrogels in practical applications are hard to meet. In this study, polyvinyl alcohol (PVA) was simply blended with a tannic acid (TA) and ferric ion (Fe3+) complex (TA-Fe3+) to prepare hydrogel materials with near-infrared (NIR) light-triggered shape memory. The introduction of TA-Fe3+ endows the hydrogel with a good photothermal effect (the temperature can be increased to 45 degrees C within 30 s). Under irradiation of near-infrared light, the hydrogel can achieve shape recovery in a short time. Due to the excellent hydrogen bonding between PVA, TA-Fe3+, and PVA chains, the hydrogels also have excellent tensile strength (3.68 MPa) and remolding properties. The PVA/TA-Fe3+ hydrogels are expected to find applications in biomedicine and intelligent engineering due to their excellent near-infrared-triggered shape memory, excellent mechanical properties, and remolding ability.