Self-Healing Hydrogel of Poly (Vinyl Alcohol)/Agarose with Robust Mechanical Property

As promising soft materials, various excellent properties of hydrogels have received widespread attention during recent years. Mechanical properties and self-healing performance are required characteristics for hydrogels in practical applications. An important challenge is to develop hydrogels exhibiting mechanical performance and self-recoverability through physical cross-linking. In this work, the authors report a hydrogel consisting of a fully physically linked poly (vinyl alcohol)/agarose (PVA/AG) dual-network, which is of high toughness and self-healing properties. The synthesis process of the PVA/AG hydrogel is convenient, with AG as the first network, and hydrogen bonding and crystal-associated PVA as the second network to form a dual physical crosslink. Due to this physical cross-linking, the PVA/AG hydrogel has good mechanical properties (tensile strength of 6.5 MPa to 14.6 MPa, ductility of 168% to 214%). The highest compressive strength of hydrogel is up to 3.66 MPa, which is almost 8 times that of pure PVA hydrogel. In addition, it has excellent self-healing properties without stimulation or healing agents. Compared to pure PVA hydrogel, PVA/AG hydrogels have higher thermal stability due to higher decomposition temperatures and lower degradation rates. In this study, the authors also initially explore the potential application of obtained hydrogel.