1D manipulation of a micrometer size particle actuated via thermocapillary convective flows

This paper deals with the open-loop characterization of a micromanipulation system actuated by thermocapillary convective flows. Micrometric size objects placed at the air/liquid interface are actuated by heating the surface of the liquid using a laser. The heat generates a surface tension gradient at the interface which induces thermocapillary convective flows that are used to move the objects. In this paper, the performances of this approach are analyzed based on open-loop experiments. Several actuation strategies are proposed and discussed. The experimental results highlight the potential of this approach since velocities up to several millimeters per second are obtained. However the precision of the positioning is not ensured by open-loop actuation, so closed-loop control will be necessary in future works. As a first step towards closed-loop control, this paper proposes a model of the system. This model is based on the open-loop experimental results, but the proposed methodology can be applied to any setup that use thermocapillary convective flows for particle manipulation.