Spreading and absorption of silicone oil droplets on silicone elastomer films

TL;DR

This paper studies how silicone oil droplets spread and absorb into soft silicone films, showing how their behavior differs from traditional wetting laws.

Contribution

The study introduces a new phenomenological model to explain droplet spreading on soft substrates, incorporating absorption and mechanical effects.

Findings

Droplet spreading on soft silicone films deviates from classical Tanner’s law.

Absorption and mechanical effects influence droplet dynamics on soft substrates.

Film thickness affects the effective stiffness and absorption potential of the system.

Abstract

When a liquid droplet completely wets a hard substrate, its spreading dynamics follow Tanner’s law, with the droplet radius growing as the one-tenth power of time. Here, we investigate how these dynamics change when silicone oil droplets spread on soft silicone elastomer and gel films supported by a rigid silicon substrate. While the droplets fully wet the elastomer surface, they also simultaneously swell the elastomer film. By varying the film thickness, we observe deviations from the classical power-law scaling, which we interpret in terms of changes to the effective stiffness and the absorption potential of the system. We describe the spreading behavior using a phenomenological model that accounts for both absorption and mechanical contributions..

Droplet spreading on a soft substrate

Figures