Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, School of Chemistry, Xi'an Jiaotong University, Xi'an, 710049, China.
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, 710049, China.
Adv Mater. 2023 Jun;35(26):e2301551. doi: 10.1002/adma.202301551. Epub 2023 May 5.
The Hoffmeister effect of inorganic salts is verified as a promising way to toughen hydrogels, however, the high concentration of inorganic salts may be accompanied by poor biocompatibility. In this work, it is found that polyelectrolytes can obviously elevate the mechanical performances of hydrogels through the Hoffmeister effect. The introduction of anionic poly(sodium acrylate) into poly(vinyl alcohol) (PVA) hydrogel induces the aggregation and crystallization of the PVA to boost the mechanical properties of the resulting double-network hydrogel: elevation of 73, 64, 28, 135, and 19 times in the tensile strength, compressive strength, Young's modulus, toughness, and fracture energy compared with poly(acrylic acid), respectively. It is noteworthy that the mechanical performances of the hydrogels can be flexibly tuned by the variation of polyelectrolyte concentration, ionization degree, relative hydrophobicity of the ionic component, and polyelectrolyte type in a wide range. This strategy is verified to work for other Hoffmeister-effect-sensitive polymers and polyelectrolytes. Also, the introduction of urea bonds into the polyelectrolyte can further improve the mechanical properties and antiswelling capability of hydrogels. As a biomedical patch, the advanced hydrogel can efficiently inhibit hernia formation and promote the regeneration of soft tissues in an abdominal wall defect model.
无机盐的霍夫迈斯特效应已被证实是一种增强水凝胶韧性的有前途的方法，然而，高浓度的无机盐可能伴随着较差的生物相容性。在这项工作中，人们发现通过霍夫迈斯特效应，聚电解质可以明显提高水凝胶的机械性能。将阴离子型聚（丙烯酸钠）引入到聚乙烯醇（PVA）水凝胶中，诱导 PVA 的聚集和结晶，从而提高所得双网络水凝胶的机械性能：与聚丙烯酸相比，拉伸强度、压缩强度、杨氏模量、韧性和断裂能分别提高了 73、64、28、135 和 19 倍。值得注意的是，通过改变聚电解质的浓度、离子化度、离子成分的相对疏水性和聚电解质的类型，可以在很宽的范围内灵活地调节水凝胶的机械性能。该策略已被验证可适用于其他对霍夫迈斯特效应敏感的聚合物和聚电解质。此外，在聚电解质中引入脲键可以进一步提高水凝胶的机械性能和抗溶胀能力。作为一种生物医学贴片，先进的水凝胶可以有效地抑制疝气形成，并促进腹壁缺损模型中软组织的再生。
