# 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.

## Key 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