title: Water Penetration through a Superhydrophobic Mesh During a Drop Impact.
abstract: When a water drop impacts a mesh having submillimeter pores, a part of the drop penetrates through the mesh if the impact velocity is sufficiently large. Here we show that different surface wettability, i.e., hydrophobicity and superhydrophobicity, leads to different water penetration dynamics on a mesh during drop impact. We show, despite the water repellence of a superhydrophobic surface, that water can penetrate a superhydrophobic mesh more easily (i.e., at a lower impact velocity) over a hydrophobic mesh via a penetration mechanism unique to a superhydrophobic mesh. On a superhydrophobic mesh, the water penetration can occur during the drop recoil stage, which appears at a lower impact velocity than the critical impact velocity for water penetration right upon impact. We propose that this unique water penetration on a superhydrophobic mesh can be attributed to the combination of the hydrodynamic focusing and the momentum transfer from the water drop when it is about to bounce off the surface, at which point the water drop retrieves most of its kinetic energy due to the negligible friction on superhydrophobic surfaces.
authors.affiliation: Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea.
authors.forename: Seunggeol
authors.initials: S
authors.lastname: Ryu
authors.affiliation: Center for Nanoscience and Engineering, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
authors.forename: Prosenjit
authors.initials: P
authors.lastname: Sen
authors.affiliation: Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea.
authors.forename: Youngsuk
authors.initials: Y
authors.lastname: Nam
authors.affiliation: Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea.
authors.forename: Choongyeop
authors.initials: C
authors.lastname: Lee