Self-propelled supramolecular nanomotors with temperature-responsive speed regulation

Self-propelled catalytic micro- and nanomotors have been the subject of intense study over the past few years, but it remains a continuing challenge to build in an effective speed-regulation mechanism. Movement of these motors is generally fully dependent on the concentration of accessible fuel, with propulsive movement only ceasing when the fuel consumption is complete. Here we report a demonstration of control over the movement of self-assembled stomatocyte nanomotors via a molecularly built, stimulus-responsive regulatory mechanism. A temperature-sensitive polymer brush is chemically grown onto the nanomotor, whereby the opening of the stomatocytes is enlarged or narrowed on temperature change, which thus controls the access of hydrogen peroxide fuel and, in turn, regulates movement. To the best of our knowledge, this represents the first nanosized chemically driven motor for which motion can be reversibly controlled by a thermally responsive valve/brake. We envision that such artificial responsive nanosystems could have potential applications in controllable cargo transportation. Effective regulation over the motion of self-propelled micro- and nanomotors is a challenging proposition. Now, self-assembled stomatocyte nanomotors with thermoresponsive polymer brushes have been designed that sense changes in local temperature and regulate the accessibility of the hydrogen peroxide fuel — thereby adjusting the speed and behaviour of nanomotor itself.