Cloaking effect on the thermocapillary motion of droplet on slippery liquid-infused porous surface

The thermocapillary motion of both cloaked and non-cloaked droplets on slippery liquid-infused porous surface were investigated experimentally. The effect of droplet radius, temperature gradient and oil viscosity on the migration velocity of droplet were considered. We found that the migration velocity of cloaked droplet was larger than that of non-cloaked droplet, which was attributed to the larger apparent radius. Through nondimensional analysis, the migration velocity of both cloaked and non-cloaked droplet followed the same linear relation with Marangoni number with slope of k = 22, which indicated that the cloaking effect actually promoted the ther-mocapillary motion of droplet on SLIPS with an external temperature gradient. In addition, the motion of oil layer underneath droplet was observed, which was responsible for the positive intercept of migration velocity.