Fluctuation assisted spreading of a fluid filled elastic blister

Abstract

In this theoretical and numerical study, we show how spatially extended fluctuations can influence and dominate the dynamics of a fluid filled elastic blister as it deforms onto a pre-wetted solid substrate. To describe the blister dynamics, we develop a stochastic elastohydrodynamic framework that couples the viscous flow, the elastic bending of the interface and the noise from the environment. We deploy a scaling analysis to find the elastohydrodynamic spreading law $\hat{R}\sim \hat{t}^{1/11}$, where $\hat{R}$ is the spreading radius and $\hat{t}$ is time, a direct analogue to the capillary spreading of drops, while the inclusion of noise in our model highlights that the dynamics speeds up significantly $\hat{R}\sim \hat{t}^{1/6}$ as local changes in curvature at the spreading front enhance the peeling of the elastic interface from the substrate. These fluctuations have a pronounced influence on the shape of the deforming blister and lead to the formation of a precursor film similar to a perfectly wetting droplet. Moreover, our analysis identifies a distinct criterion for the transition between the deterministic and the stochastic spreading regime, which is further illustrated by numerical simulations.