Self-propelled Nanoparticles

Chemically active particles that self-propel due to catalytic reactions have been demonstrated at various length scales. It has, however, not yet been experimentally established how the propulsion of very small chemical motors scales with size. For this reason, we use a unique physical nanofabrication technique, based on physical vapor deposition, to grow catalytically-active Janus particles. These can be grown at defined lengths ranging from 20nm to 500nm, and can contain photocatalytic materials. This allows us to switch the particle between its passive and active state and thereby potentially from Brownian to enhanced diffusion. The observation of the particles’ motion is, however, far from trivial. We report our latest experimental results from a variety of analytical techniques, some of which can be used in situ.