End-block length dependence of the hydrogel relaxation dynamics was investigated using PEO-based ABA triblock copolymer solutions in an aqueous solvent. Both ends of PEO were capped with hydrophobic poly(isopropyl glycidyl ether-co-ethyl glycidyl ether) exhibiting a lower critical solution temperature (LCST) behavior, resulting in the transition between sol and gel with temperature. Despite the nearly identical hydrophobicity of the end-blocks, the sol-to-gel transition temperature is found to be significantly dependent on the end-block length. Particularly, a small increment of the end-block length leads to significantly slower relaxation dynamics which is attributed to the thermodynamic barrier of end-block extraction. Hydrogels with an appropriate relaxation time show excellent injectability and self-healing ability, yet extremely slow relaxation dynamics result in brittle hydrogels. These results are discussed in terms of current understanding of the hydrogel relaxation dynamics and particular attention is paid to the issue of the chain dynamics between aggregated cores.

使用基于 PEO 的 ABA 三嵌段共聚物溶液在水性溶剂中研究了水凝胶弛豫动力学的末端嵌段长度依赖性。PEO的两端用疏水性聚（异丙基缩水甘油醚-加盖共-乙基缩水甘油醚）表现出较低的临界溶解温度（LCST）行为，导致溶胶和凝胶之间随温度的转变。尽管末端嵌段的疏水性几乎相同，但发现溶胶到凝胶的转变温度显着取决于末端嵌段长度。特别是，端块长度的小增量会导致松弛动力学显着变慢，这归因于端块提取的热力学障碍。具有适当弛豫时间的水凝胶显示出优异的可注射性和自愈能力，但极慢的弛豫动力学会导致水凝胶变脆。这些结果根据目前对水凝胶松弛动力学的理解进行了讨论，并特别关注聚集核之间的链动力学问题。