Surfactant-Mediated Sliding of Aqueous Droplets on Smooth Solid Surfaces

Slippery surfaces on which liquid droplets display high mobility have attracted great interest due to their wide range of applications. Immense research efforts have been devoted to the development of novel slippery surfaces with tailored functions. Prior studies have focused mainly on super-repellent surfaces and lubricant-infused surfaces, which possess superior slipperiness. However, these surfaces typically require creation of micro/nano surface textures and surface chemistry modification through complex processes. Unlike prior work, this study introduces a novel strategy to induce the sliding of aqueous droplets on smooth solid surfaces. We show that droplets containing ionic surfactants display high mobility on the solid surfaces without morphology and chemistry modification. The sliding behavior of the droplet is regulated by the surfactant concentration. Furthermore, we demonstrate the controlled manipulation of the surfactant-laden droplets.