Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 6158510, Japan.
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 9201192, Japan.
Chemistry. 2021 Apr 12;27(21):6435-6439. doi: 10.1002/chem.202005099. Epub 2021 Feb 5.
Poly(ethylene oxide)s (PEOs) are useful polymers with good water solubility, biological compatibility, and commercial availability. PEOs with various end groups were threaded into pillar[5]arene rings in a mixture of water and methanol to afford pseudopolyrotaxanes. Corresponding polyrotaxanes were also constructed by capping COOH-terminated pseudopolyrotaxanes with bulky amines, in which multiple hydrogen bonds involving the pillar[5]arene OH groups were critically important to prevent dethreading. The number of threaded ring components could be rationally controlled in these materials, providing a simple and versatile method to tune the mechanical and thermal properties. Specifically, a polyrotaxane with a high-molecular-weight axle became elastic upon heating above the melting point of PEOs and exhibited temperature-dependent shape memory property because of the topological confinement and crosslinked hydrogen bonds.
聚环氧乙烷（PEOs）是一种具有良好水溶性、生物相容性和商业可用性的有用聚合物。将具有各种端基的 PEOs 穿入水和甲醇混合物中的杯[5]芳烃环中，得到假轮烷。通过用大体积胺封端 COOH 端接的假轮烷，也构建了相应的聚轮烷，其中涉及杯[5]芳烃 OH 基团的多个氢键对于防止解旋至关重要。在这些材料中，可以合理控制穿入的环组件的数量，提供了一种简单而通用的方法来调节机械和热性能。具体而言，当加热到 PEOs 的熔点以上时，具有高分子量轴的聚轮烷变得有弹性，并由于拓扑限制和交联氢键而表现出温度依赖性形状记忆特性。
