水凝胶承受各种动态应力,要求强大的机械性能。尽管取得了重大进展,在不使用潜在有害交联剂的情况下,将水凝胶强度与生物组织和塑料相匹配通常具有挑战性。使用氢键作为牺牲键提供了一种有希望的策略来产生坚韧的,用于生物医学和工业应用的多功能水凝胶。通过热诱导自由基聚合合成了聚(甲基丙烯酸)(PMA)/明胶水凝胶,并仅通过物理键进行交联,不添加任何化学交联剂。明胶的添加增加了水凝胶结构中疏水结构域的形成,作为永久交联点。PMA和明胶含量的增加通常导致较低的平衡水含量(WC),更高的热稳定性和更好的机械性能。抗拉强度和韧性值分别达到1.44±0.17MPa和4.91±0.51MJm-3,而压缩模量和强度达到0.75±0.06MPa和24.81±5.85MPa,分别,WC高于50wt。%.获得的压缩机械性能值与文献中报道的超强水凝胶相当。此外,水凝胶表现出优异的耐疲劳性和生物相容性,以及出色的形状记忆特性,这使它们成为广泛生物医学应用的突出候选者。
Hydrogels endure various dynamic stresses, demanding robust mechanical properties. Despite significant advancements, matching hydrogels\' strength to biological tissues and plastics is often challenging without applying potentially harmful crosslinkers. Using hydrogen bonds as sacrificial bonds offers a promising strategy to produce tough, versatile hydrogels for biomedical and industrial applications. Poly(methacrylic acid) (PMA)/gelatin hydrogels were synthesized by thermally induced free-radical polymerization and crosslinked only by physical bonds, without adding any chemical crosslinker. The addition of gelatin increased the formation of hydrophobic domains in the structure of the hydrogels, which acted as permanent crosslinking points. The increase in PMA and gelatin contents generally led to a lower equilibrium water content (WC), higher thermal stability and better mechanical properties. The values of tensile strength and toughness reached up to 1.44 ± 0.17 MPa and 4.91 ± 0.51 MJ m-3, respectively, while the compressive modulus and strength reached up to 0.75 ± 0.06 MPa and 24.81 ± 5.85 MPa, respectively, with the WC being higher than 50 wt.%. The obtained values for compressive mechanical properties are comparable with super-strong hydrogels reported in the literature. In addition, hydrogels exhibited excellent fatigue resistance and biocompatibility, as well as great shape memory properties, which make them prominent candidates for a wide range of biomedical applications.