Switchable Polymer Materials Controlled by Rotaxane Macromolecular Switches

-ammonium salt/crown ether couples. The successful synthesis of M2Rs possessing a single polymer axle and one crown ether wheel, constituting a key component of the macromolecular switch, has allowed us to develop various unique applications such as the development of topology-transformable polymers. Polymer topological transformations (e.g., linear-star and linear-cyclic) are achieved using rotaxane-linked polymers and rotaxane macromolecular switches. The pronounced dynamic nature of these polymer systems is sufficiently interesting to design sophisticated stimuli-responsive molecules, polymers, and materials.