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Title: Numerical study of the effects of surface topography and chemistry on the wetting transition using the string method

Droplets on a solid surface patterned with microstructures can exhibit the composite Cassie-Baxter (CB) state or the wetted Wenzel state. The stability of the CB state is determined by the energy barrier separating it from the wetted state. In this work, we study the CB to Wenzel transition using the string method [E et al., J. Chem. Phys. 126, 164103 (2007); W. Ren and E. Vanden-Eijnden, J. Chem. Phys. 138, 134105 (2013)]. We compute the transition states and energy barriers for a three-dimensional droplet on patterned surfaces. The liquid-vapor coexistence is modeled using the mean field theory. Numerical results are obtained for surfaces patterned with straight pillars and nails, respectively. It is found that on both type of surfaces, wetting occurs via infiltration of the liquid in a single groove. The reentrant geometry of nails creates large energy barrier for the wetting of the solid surface compared to straight pillars. We also study the effect of surface chemistry, pillar height, and inter-pillar spacing on the energy barrier and compare it with nails.
Authors:
 [1] ;  [2] ;  [3]
  1. School of Mathematical Sciences, Soochow University, Suzhou 215006 (China)
  2. Department of Mathematics, National University of Singapore, Singapore 119076 (Singapore)
  3. (Singapore)
Publication Date:
OSTI Identifier:
22415440
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMISTRY; COMPARATIVE EVALUATIONS; DROPLETS; LIQUIDS; MEAN-FIELD THEORY; MICROSTRUCTURE; NUMERICAL ANALYSIS; SOLIDS; STABILITY; SURFACES; THREE-DIMENSIONAL CALCULATIONS; TOPOGRAPHY; VAPORS