Department of Materials Science and Engineering, University of Sheffield , Mappin Street, Sheffield S1 3JD, United Kingdom.
Department of Mechanical Engineering, University College London , Torrington Place, London WC1E 7JE, United Kingdom.
ACS Appl Mater Interfaces. 2017 Jul 12;9(27):22223-22234. doi: 10.1021/acsami.7b05261. Epub 2017 Jun 26.
Highly stretchable and highly resilient polymer-clay nanocomposite hydrogels were synthesized by in situ polymerization of acrylamide in the presence of pristine montmorillonite (MMT) or chitosan-treated MMT nanoplatelets at an elevated temperature. Both nanocomposite hydrogels can be stretched to a strain of no less than 1290%. The treatment of clay with chitosan improves the tensile strength, elongation at break, and energy at break of the nanocomposite hydrogel by 237%, 102%, and 389%, respectively, due to the strong chitosan-MMT electrostatic interaction and the grafting of polyacrylamide onto chitosan chains. Both hydrogels display excellent resilience with low hysteresis; with a maximum tensile strain of 50%, ultralow hysteresis is found, while, with a maximum strain of 500%, both hydrogels fully recover their original state in just 1 min. The superb resilience of the nanocomposite hydrogels is attributed to the strong interactions within the hydrogels brought by chain branching, multiple hydrogen bonding, covalent bonding, and/or electrostatic force. The hydrogels can be fabricated into different shapes and forms, including microfibers spun using pressurized gyration, which may find a variety of potential applications in particular in healthcare.
通过在高温下存在原始蒙脱土（MMT）或壳聚糖处理的 MMT 纳米片的情况下原位聚合丙烯酰胺，合成了高拉伸和高弹性的聚合物-粘土纳米复合材料水凝胶。两种纳米复合材料水凝胶都可以拉伸至应变不小于 1290%。壳聚糖处理粘土可分别提高纳米复合材料水凝胶的拉伸强度、断裂伸长率和断裂能 237%、102%和 389%，这是由于强的壳聚糖-MMT 静电相互作用和聚丙烯酰胺接枝到壳聚糖链上。两种水凝胶都表现出优异的弹性和低滞后性；在最大拉伸应变为 50%时，发现超低滞后性，而在应变最大为 500%时，两种水凝胶都在 1 分钟内完全恢复到原来的状态。纳米复合材料水凝胶的高弹性归因于链支化、氢键、共价键和/或静电力在水凝胶内产生的强相互作用。这些水凝胶可以被制成不同的形状和形式，包括使用加压旋转纺丝制成的微纤维，这可能在医疗保健等特定领域有多种潜在应用。
