On the Thermocapillary Migration on Radially Microgrooved Surfaces.

Thermocapillary migration describes the phenomenon in which a droplet placed on a nonuniformly heated surface can migrate from warm to cold regions. Herein, we report an experimental investigation of the migration of silicone oil droplets on radially microgrooved surfaces subjected to a thermal gradient; the effects of the initial divergence angle and divergent direction on the migration behavior are highlighted. A theoretical model is established to predict the migration velocity considering the thermocapillary, viscous resistance, and radial structure-induced forces; furthermore, the proposed theoretical derivation is validated. This study advances the understanding of this interfacial phenomenon, which has great potential for regulating and controlling liquid motion in lubrication systems, condensation and heat-transfer devices, and open microfluidics.