Abstract
Contactless droplet transport has gained intensive attention in recent years. In this study, the motion of a sessile binary droplet or a pure water droplet under the contactless Marangoni effect has been investigated experimentally and theoretically. The concrete form of the driving force originates from the evaporation of a pure liquid "source" droplet was achieved and verified by our experimental data. For a "target" droplet consisting of pure water, we discovered a non-negligible increase in its spreading radius R during motion. Based on the experimental results, we proposed a linear approximation between R and the droplet spacing and successfully introduced its influence on the driving force calculation through the perturbation theory. (c) 2021 Author(s).