Microscale Marangoni Surfers

Abstract

We apply laser light to induce the asymmetric heating of Janus colloids adsorbed at water-oil interfaces and realize active micrometric "Marangoni surfers". The coupling of temperature and surfactant concentration gradients generates Marangoni stresses leading to self-propulsion. Particle velocities span four orders of magnitude, from microns/s to cm/s, depending on laser power and surfactant concentration. Experiments are rationalized by finite elements simulations, defining different propulsion regimes relative to the magnitude of the thermal and solutal Marangoni stress components.

main: 6 pages, 4 figures; supplemental: 18 pages, 11 figures

References in corpus (6)

• Induced-charge Electrophoresis of Metallo-dielectric Particles
• Viscous Marangoni propulsion
• Tuning the motility and directionality of self-propelled colloids
• Thermally driven Marangoni surfers
• Visco-elastic drag forces and crossover from no-slip to slip boundary conditions for flow near air-water interfaces
• Effect of surface-active contaminants on radial thermocapillary flows