Wetting on physically patterned solid surfaces: the relevance of molecular dynamics simulations to macroscopic...

Area of Science:

• Physics
• Materials Science
• Computational Science

Background:

• Understanding droplet behavior on patterned surfaces is crucial for various applications, including microfluidics and materials engineering.
• Surface topography significantly influences droplet wetting properties, leading to complex behaviors.

Purpose of the Study:

• To investigate the wetting of Lennard-Jones cylindrical droplets on surfaces with groove patterns using molecular dynamics (MD) simulations.
• To determine if droplet wetting behavior and contact angles are size-dependent on patterned surfaces.
• To compare simulation results with established mathematical models for droplet free energy.

Main Methods:

• Employing molecular dynamics (MD) simulations to model droplet-surface interactions.
• Utilizing scaled surface topography parameters relative to droplet size.
• Developing phase diagrams to map wetting modes against surface topographical parameters.

Main Results:

• Droplet wetting modes and contact angles were found to be independent of droplet size when surface topography parameters were scaled accordingly.
• MD-derived contact angles showed good agreement with predictions from a mathematical model for small Bond numbers.
• Phase diagrams successfully predicted multiple wetting modes based on surface topography, consistent with experimental observations.

Conclusions:

• MD simulations provide valuable insights into the large-length-scale wetting behavior of droplets on patterned surfaces.
• The size-independence of wetting modes, under scaled topography, simplifies the understanding of droplet-surface interactions.
• This study bridges the gap between atomistic simulations and macroscopic wetting phenomena.