Light Driven Fuel-Free Thermocapillary Microswimmers

Surface tension is a powerful agent for driving biological and artificial micron-sized particles. Surface tension gradients however, typically require a chemical reaction, making a capillary based swimmer fuel dependent. By combining a light absorbing bead with a fluid droplet we made a dimer that is propelled by light, and requires no chemical fuel. The 6 μm swimmers’ motility records over 10 μm/s and show good with measured thermocapillary and hydrodynamic parameters. We discuss the swimmers’ manipulation and interactions.