Topology-transformable block copolymers based on a rotaxane structure: change in bulk properties with same composition

Hiroki Sato,Daisuke Aoki,Hironori Marubayashi,Teruaki Hayakawa,Ken Nakajima,Toshikazu Takata,Hiromitsu Sogawa,Xiaobin Liang,Shuichi Nojima,Satoshi Uchida

doi:10.1038/s41467-021-26249-0

Hiroki Sato, Daisuke Aoki + Show 8 more

Open Access

https://doi.org/10.1038/s41467-021-26249-0

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Abstract

The topology of polymers affects their characteristic features, i.e., their microscopic structure and macroscopic properties. However, the topology of a polymer is usually fixed during the construction of the polymer chain and cannot be transformed after its determination during the synthesis. In this study, topology-transformable block copolymers that are connected via rotaxane linkages are introduced. We will present systems in which the topology transformation of block copolymers changes their 1) microphase-separated structures and 2) macroscopic mechanical properties. The combination of a rotaxane structure at the junction point and block copolymers that spontaneously form microphase-separated structures in the bulk provides access to systems that cannot be attained using conventional covalent bonds.

Highlights

The topology of polymers affects their characteristic features, i.e., their microscopic structure and macroscopic properties
Two types of block copolymers whose topology can be transformed via a movable rotaxane linkage at their junction point were synthesized
Such block copolymers represent a system in which the topology transformation of the polymer changes the microphase-separated structure and macroscopic mechanical properties

Summary

Introduction

The topology of polymers affects their characteristic features, i.e., their microscopic structure and macroscopic properties. The initial microphase-separated structure of the multicomponent polymer system is converted by a polymer topology transformation via a movable rotaxane linkage at the junction point. The transformation of the ABC terpolymer from a star-shaped (ABCstar) to a linear (ABClinear) topology, which is due to the interaction change from sec-ammonium/crown ether to urethane linkage/crown ether[19,20,21], was achieved via the acetylation of the sec-ammonium moiety in the center of the polymer chain in ABCstar.

Results

Conclusion