Enhanced Dip Coating on a Soft Substrate
Abstract
A solid, withdrawn from a liquid bath, entrains a thin liquid film. This simple process, first described by Landau, Levich and Derjaguin (LLD), is commonly observed in everyday life. It also plays a central role in liquid capture by animals, and is widely used for surface-coating purposes in industry. Motivated by the emerging interest in the mechanics of very soft materials, and in particular the resulting elastocapillary coupling, we develop a dip-coating model that accounts for the additional presence of a soft solid layer atop the rigid plate. The elastic response of this soft layer is described by a Winkler's foundation. Using a combination of numerical, scaling and asymptotic-matching methods, we find a new softness-dependent power-law regime for the thickness of entrained liquid at small capillary number, which corresponds to a modified physics at play in the dynamic meniscus. The crossover between this regime and the classical dip-coating one occurs when the substrate's deformation is comparable to the thickness of the entrained liquid film.
Cite
@article{arxiv.2203.00322,
title = {Enhanced Dip Coating on a Soft Substrate},
author = {Vincent Bertin and Jacco Snoeijer and Elie Raphaël and Thomas Salez},
journal= {arXiv preprint arXiv:2203.00322},
year = {2022}
}