In this review article, we discuss the synthesis and dynamic nature of macromolecular systems that have mechanically linked polymer chains capable of undergoing a topology transformation driven by a rotaxane molecular switch. The rotaxane linking of polymer chains plays a crucial role in these systems. A linear polymer possessing a crown ether/sec-ammonium salt-type [1]rotaxane moiety at the axle chain terminal was prepared via the rotaxane linking of a single polymer chain. A linear–cyclic polymer topology transformation was achieved via the movement of the wheel component from one end to the other end of the axle component using the rotaxane macromolecular switch function. The successful synthesis of a macromolecular [2]rotaxane (M2R) possessing a single polymer axle and one crown ether wheel led to a variety of unique applications, such as the development of topology-transformable polymers and the synthesis of rotaxane crosslinked polymers (RCPs). The introduction of a polymer chain to the wheel component of M2R (rotaxane linking of two polymer chains) produced a rotaxane-linked AB block copolymer that transformed its topology from linear to branched. Furthermore, a rotaxane-linked three-component polymer and an ABC triblock copolymer were synthesized and transformed to the corresponding 3-arm star (co)polymers, and the transformation was confirmed by measuring the hydrodynamic volume change. The structural transformation of 4-arm and 6-arm star polymers was also accomplished using the dynamic mobility of a similar rotaxane. As a useful application, M2R-based vinylic crosslinkers (RCs) were prepared and applied to the synthesis of RCPs, whereby the addition of RCs into radical polymerization systems of vinyl monomers afforded polymers with excellent toughness by enhancing both of tradeoff properties that cannot be achieved using typical covalent crosslinkers. Synthesis and dynamic nature of macromolecular systems having mechanically linked polymer chains, which can undertake the topology transformation, are described. The rotaxane linking of polymer chains plays a crucial role in these systems. Successful syntheses of macromolecular [2]rotaxane (M2R) possessing single polymer axle and one crown ether wheel made possible the development of topology-transformable polymers from star to linear. Furthermore, rotaxane-linked ABC triblock copolymer and 4-arm and 6-arm star polymers were also synthesized and transformed to other topological polymers along with the property change.

中文翻译：

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拓扑可转换聚合物：通过聚合物链的机械连接进行线性支化聚合物结构转变

在这篇评论文章中，我们讨论了具有机械连接聚合物链的大分子系统的合成和动态性质，这些聚合物链能够经历由轮烷分子开关驱动的拓扑转换。聚合物链的轮烷连接在这些系统中起着至关重要的作用。在轴链末端具有冠醚/仲铵盐型[1]轮烷部分的线性聚合物是通过单个聚合物链的轮烷连接制备的。使用轮烷大分子开关功能，通过轮组件从轴组件的一端移动到另一端，实现了线性-环状聚合物拓扑转换。具有单个聚合物轴和一个冠醚轮的大分子 [2] 轮烷 (M2R) 的成功合成导致了各种独特的应用，例如拓扑可转化聚合物的开发和轮烷交联聚合物（RCPs）的合成。将聚合物链引入 M2R 的轮组件（两个聚合物链的轮烷连接）产生了轮烷连接的 AB 嵌段共聚物，将其拓扑结构从线性转变为支化。此外，轮烷连接的三组分聚合物和 ABC 三嵌段共聚物被合成并转化为相应的 3 臂星形（共）聚合物，并通过测量流体力学体积变化来确认转化。4 臂和 6 臂星形聚合物的结构转变也是使用类似轮烷的动态迁移率完成的。作为一个有用的应用，基于 M2R 的乙烯基交联剂 (RCs) 被制备并应用于 RCPs 的合成，因此，将 RC 添加到乙烯基单体的自由基聚合体系中，通过增强使用典型共价交联剂无法实现的两种权衡特性，为聚合物提供了优异的韧性。描述了具有机械连接聚合物链的大分子系统的合成和动态性质，可以进行拓扑转换。聚合物链的轮烷连接在这些系统中起着至关重要的作用。具有单聚合物轴和一个冠醚轮的大分子 [2] 轮烷 (M2R) 的成功合成使拓扑可转换聚合物从星形到线性的发展成为可能。此外，还合成了轮烷连接的 ABC 三嵌段共聚物和 4 臂和 6 臂星形聚合物，并随着性能的变化转化为其他拓扑聚合物。