Synthetic Molecular Motors and Mechanical Machines

Graphical Abstract

Exercising demons: Although the notion of synthetic molecular-level motors and machines has been around for 150 years (for example, Maxwell's demon, see picture), it is only recently that research in this area has flourished. The current state of the art in regard to how the components of molecular-level structures can be switched, rotated, speeded up, slowed down, and directionally driven in response to stimuli is described in the Review.

Abstract

The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.