Numerical study of the wetting and mobility of liquid droplets on horizontal and inclined flat and microgrooved surfaces

Abstract

Designing hydrophobic surfaces with controllable wettability has attracted much interest in the recent times. The present study seeks to simulate the static and dynamic wetting behavior of liquid droplets on horizontal flat and microgrooved surfaces and compare the findings with experimentally obtained data. Using an open-source software, a 3D drop-shape model is developed to numerically analyze the shape of liquid droplets and anisotropic wetting for a wide range of parametric space. The effects of droplet volume, variation in the microgroove geometry and wettability gradient along the parallel and perpendicular directions of the microgrooved surfaces etc. on the drop shape and apparent contact angle are examined. Simulation and analysis are extended to analyze the wetting behavior of V-grooved geometry and are compared with the findings on rectangular microgrooved surfaces. For creating wettability gradient along the parallel direction of the grooves, periodic PDMS (Polydimethylsiloxane) coating is considered and increased hydrophobicity of the surface is observed with significant increase in the parallel contact angle for this case. The simulated results manifest considerable differences in the wetting pattern of the microgrooved and flat surfaces and are found out to be in good agreement with the experimental findings.