Two modes of contact-time reduction in the impact of particle-coated droplets on superhydrophobic surfaces

Abstract

Reducing the contact time during droplet impact is essential for many scientific and industrial applications, such as self-cleaning, anti-icing, heat transfer, and condensation. This paper reports contact-time reduction by coating droplets with micro–nano hydrophobic particles. Such particle-coated droplets are known as liquid marbles (LM). LM impact on superhydrophobic surfaces reveals two different modes of contact-time reduction. For lower impact energies, the reduced adhesion of LM with the surface is responsible for a reduction of up to 21%. Contact-time reduction in this regime is found to be independent of particle size but dependent on the solid fraction of LM. However, a fragmentation-based contact-time reduction is observed for larger particle sizes and higher impact energies. Here, the reduction is as high as 65%. Such fragmentation occurs because the spreading LM lamella breaks when its thickness becomes similar to particle dimensions. Our findings reveal the potential of LM as a novel approach to reduce contact time during droplet impact, with implications for various scientific and industrial applications.