Initial spreading of low-viscosity drops on partially wetting surfaces

TL;DR

This study investigates the initial rapid spreading of low-viscosity drops on partially wetting surfaces using molecular dynamics and high-speed imaging, revealing a wettability-independent spreading regime where the contact radius grows as the square root of time.

Contribution

It provides new insights into the initial spreading dynamics at small scales, showing a universal spreading behavior regardless of surface wettability.

Findings

Contact radius grows as square root of time

Spreading regime is independent of wettability

Accessed previously unexplored length- and time-scales

Abstract

Liquid drops start spreading directly after brought into contact with a partial wetting substrate. Although this phenomenon involves a three-phase contact line, the spreading motion is very fast. We study the initial spreading dynamics of low-viscosity drops, using two complementary methods: Molecular Dynamics simulations and high-speed imaging. We access previously unexplored length- and time-scales, and provide a detailed picture on how the initial contact between the liquid drop and the solid is established. Both methods unambiguously point towards a spreading regime that is independent of wettability, with the contact radius growing as the square root of time.