title: From sticky to slippery droplets: dynamics of contact line depinning on superhydrophobic surfaces.
abstract: This study explores how surface morphology affects the dynamics of contact line depinning of an evaporating sessile droplet on micropillared superhydrophobic surfaces. The result shows that neither a liquid-solid contact area nor an apparent contact line is a critical physical parameter to determine the depinning force. The configuration of a contact line on a superhydrophobic surface is multimodal, composed of both two phases (liquid and air) and three phases (liquid, solid, and air). The multimodal state is dynamically altered when a droplet recedes. The maximal three-phase contact line attainable along the actual droplet boundary is found to be a direct and linear parameter that decides the depinning force on the superhydrophobic surface.
authors.affiliation: Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Chang-Hwan
authors.initials: CH
authors.lastname: Choi