Shear-induced assembly of a transient yet highly stretchable hydrogel based on pseudopolyrotaxanes
Shear-induced assembly of a transient yet highly stretchable hydrogel based on pseudopolyrotaxanes
复制标题
基于准聚轮烷的瞬时但高度可拉伸的水凝胶的剪切诱导组装
DOI：
10.1038/s41557-019-0235-8
复制
发表时间：
2019-05-01
期刊：
影响因子：
21.8
通讯作者：
Jiang, Wei
中科院分区：
文献类型：
--
作者：
Ke, Hua;Yang, Liu-Pan;Jiang, Wei
耗散自组装在生物系统中很常见，它通过消耗燃料来维持远离平衡的功能状态。合成耗散系统已经制备，可以模仿生物系统的一些特性，但它们往往表现出较差的机械性能。在这里，我们报告了剪切诱导的瞬态水凝胶，是高度可拉伸的。该系统是通过将Cu（II）加入到pseudopolyrotaxane的水溶液中来构建的，pseudopolyrotaxane本身是通过在聚乙二醇链上穿过分子管而形成的。剧烈摇动将溶液转化为凝胶，随着时间的推移，凝胶逐渐松弛回到溶胶状态。这个循环可以重复至少五次。提出了一种机制，依赖于从链内到链间协调和随后的热弛豫剪切诱导的过渡。远离平衡的水凝胶是高度可拉伸的，这可能是由于聚乙二醇链上的分子管的“摩擦”滑动。在摇动时，水凝胶经历快速的自我修复。
Dissipative self-assembly is common in biological systems, where it serves to maintain a far-from-equilibrium functional state through fuel consumption. Synthetic dissipative systems have been prepared that can mimic some of the properties of biological systems, but they often show poor mechanical performance. Here, we report a shear-induced transient hydrogel that is highly stretchable. The system is constructed by adding Cu(ii) into the aqueous solution of a pseudopolyrotaxane, which is itself formed by threading molecular tubes on polyethylene glycol chains. Vigorous shaking transforms the solution into a gel, which gradually relaxes back to the sol state over time. This cycle can be repeated at least five times. A mechanism is proposed that relies on a shear-induced transition from intrachain to interchain coordination and subsequent thermal relaxation. The far-from-equilibrium hydrogel is highly stretchable, which is probably due to ‘frictional’ sliding of the molecular tubes on the polyethylene glycol chains. On shaking, the hydrogel undergoes fast self-healing.