Rotaxanes are molecules where one or more ring components is threaded onto an axle that is capped on both ends with stoppers to prevent the rings from falling off. One of the most interesting features of these rotaxanes is the ability to move an interlocked ring along the axle. By tuning (chemically, electrically, and optically) strong enthalpic interactions within the molecule, researchers can entice a ring to cover specific portions of the axle, creating a molecular switch. Since 2010, we have constructed theoretically-based designs of rotaxane-based molecular machines. These machines are (1) piston-rotaxane, a simple molecular machine designed to dissipate mechanical energy like a molecular scale automobile shock adsorber, and (2) a molecular screw, where rotation and translation of rings about and along the axle are coupled. Other rotaxane systems that we are working on include include single polyrotaxane moelcules, polyrotaxane gels and brushes
Our aim is to continue development of theory and simulation of rotaxanes using statistical thermodynamics towards synthesis and single molecule force spectroscopy.