Suppressing rotational diffusion of Janus particles by surface modifications for directed thermophoretic motion

Here, the influence of various surface modifications on self-propelled motion of laser-heated goldcapped Janus particles is investigated. Wide-field laser heating of the gold hemisphere induces an asymmetric temperature profile around the particles resulting in thermophoretic self-propulsion [1]. Besides the desired directed translational motion also rotational diffusion of the Janus particles has to be regarded [2]. Therefore, we modified the Janus particles with linear DNA strands to stabilize the self-driven thermophoretic motion against the rotational diffusion. In addition, by changing the surface properties of the confining microfluidic chambers, the orientation of Janus particle was also affected. Furthermore, linking polystyrene microspheres to Janus particles via linear double-stranded DNA was investigated as a model system for transport of microcargo.