Polymer Mechanochemistry of Component Parts for Artificial Molecular Machines

A huge variety of synthetic molecular machines and their components are developed, and their actuation at the molecular level is demonstrated and used in microscopic molecular systems and macroscopic materials. Not only the actuation but also their mechanical responses are critical to the applications. In other words, a molecular machine or a machine part insensitive to mechanical forces can produce mechanical work by another external stimulus even under mechanical loading as an actuator, whereas that sensitive to mechanical forces can be controlled to generate motions by mechanical forces as a mechanophore. To explore the mechanical response empirically, a molecular machine or a part of it has to be chemically incorporated in a polymer chain, through which elongational forces can be applied to the embedded molecule. Here, the mechanochemistry of component parts is reviewed for artificial molecular machines represented by photoswitches and mechanically interlocked architectures using polymer mechanochemistry. Artificial molecular machines receive significant interest as the smallest machines from not only chemistry but also material science and material development. The mechanical responses as well as the actuation of the machines and components are critical to the applications. In this review, the polymer mechanochemistry of component parts is highlighted for synthetic molecular machines such as photoswitches and mechanical bonds.image