Droplets Can Rebound toward Both Directions on Textured Surfaces with a Wettability Gradient

Bo Zhang, Qing Lei, Zuankai Wang, Xianren Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

44 Citations (Scopus)

Abstract

The impact of water droplets on superhydrophobic surfaces with a wettability gradient is studied using the lattice Boltzmann simulation. Droplets impacting such textured surfaces have been previously reported to rebound obliquely following the wettability gradient due to the unbalanced interfacial forces created by the heterogeneous architectures. Here we demonstrate that droplets can rebound toward both directions on textured surfaces with a wettability gradient. Our simulation results indicate that the rebound trajectory of droplets is determined by the competition between the lateral recoil of the liquid and the penetration and capillary emptying of the penetrated liquid from the textures in the vertical direction. When the time scale for the droplet penetration and capillary emptying process is smaller than the time for the lateral spreading, the droplet will rebound following the wettability gradient. By contrast, the droplet will display a bouncing against the wettability gradient direction because of the significant capillary penetration and emptying in the transverse direction. We believe that our study provides important insight for the design of micro/nanotextured surfaces for controlled droplet manipulation.

Original languageEnglish
Pages (from-to)346-351
Number of pages6
JournalLangmuir
Volume32
Issue number1
DOIs
Publication statusPublished - 12 Jan 2016
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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