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arXiv · 2203.00322

Enhanced Dip Coating on a Soft Substrate

Vincent Bertin·Jacco Snoeijer·Elie Raphaël·Thomas Salez
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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A solid, withdrawn from a liquid bath, entrains a thin liquid film.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.

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Vincent Bertin, Jacco Snoeijer, Elie Raphaël, Thomas Salez. 2022-03-01. Enhanced Dip Coating on a Soft Substrate. https://arxiv.org/abs/2203.00322

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