Due to the good biocompatibility, polyvinyl alcohol (PVA) hydrogels have attracted the attention of many biomaterial researchers. However, the low strength and poor toughness of pure PVA hydrogel prepared by freeze–thaw method limit the application. In this study, silica was used to enhance the performances of PVA hydrogel. Different from previous PVA/SiO₂ hydrogels, urea was used to regulate the formation and distribution of silica in PVA, which greatly improved the mechanical properties of hydrogels. The tensile stress and toughness of the obtained PVA(Urea)/SiO₂ hydrogels reached 8.10 MPa and 44.45 MJ/m³, which were 39 times and 212 times as that of pure PVA hydrogel, respectively. In PVA(Urea)/SiO₂ hydrogels, SiO₂ had both strengthening and toughening effects on hydrogels, which is very different from the ordinary composite hydrogels. In addition, PVA(Urea)/SiO₂ hydrogels showed unique self-reinforcing characteristics with increasing the number of tensile recoveries in cyclic stretching and recovery tests. Thus, PVA(Urea)/SiO₂ hydrogel with high strength and toughness, constructed by a simple strategy, is a potential candidate in cartilage repair.

由于良好的生物相容性，聚乙烯醇（PVA）水凝胶引起了许多生物材料研究者的关注。然而，冻融法制备的纯PVA水凝胶强度低、韧性差，限制了其应用。在这项研究中，二氧化硅被用来增强 PVA 水凝胶的性能。与以往的PVA/SiO ₂水凝胶不同，本发明采用尿素来调节PVA中二氧化硅的形成和分布，大大提高了水凝胶的力学性能。所得PVA(Urea)/SiO ₂水凝胶的拉伸应力和韧性达到8.10 MPa和44.45 MJ/m ³ ,分别是纯PVA水凝胶的39倍和212倍。在PVA(Urea)/SiO ₂水凝胶中，SiO ₂对水凝胶同时具有增强和增韧的作用，这与普通复合水凝胶有很大不同。此外，PVA(尿素)/SiO ₂水凝胶在循环拉伸和恢复测试中随着拉伸恢复次数的增加而表现出独特的自增强特性。因此，通过简单的策略构建的具有高强度和韧性的PVA(尿素)/SiO _{2水凝胶是软骨修复的潜在候选者。}