Influence of surface roughness on superhydrophobicity

TL;DR

This study uses molecular dynamics simulations to analyze how surface roughness influences superhydrophobicity, revealing that nanodroplet contact angles are mainly affected by roughness amplitude rather than fractal dimension.

Contribution

It provides new insights into the role of surface roughness parameters on superhydrophobicity using molecular dynamics simulations.

Findings

Contact angle depends strongly on roughness amplitude.

Contact angle is nearly independent of fractal dimension D_f.

Results help in designing surfaces with desired superhydrophobic properties.

Abstract

Superhydrophobic surfaces, with liquid contact angle theta greater than 150 degree, have important practical applications ranging from self-cleaning window glasses, paints, and fabrics to low-friction surfaces. Many biological surfaces, such as the lotus leaf, have hierarchically structured surface roughness which is optimized for superhydrophobicity through natural selection. Here we present a molecular dynamics study of liquid droplets in contact with self-affine fractal surfaces. Our results indicate that the contact angle for nanodroplets depends strongly on the root-mean-square surface roughness amplitude but is nearly independent of the fractal dimension D_f of the surface.