Non-monotonic motion of sliding droplets on strained soft solids

Fuente: arXiv
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Main Authors: Chao, Youchuang, Jeon, Hansol, Karpitschka, Stefan
Format: Preprint
Published: 2024
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author Chao, Youchuang
Jeon, Hansol
Karpitschka, Stefan
author_facet Chao, Youchuang
Jeon, Hansol
Karpitschka, Stefan
contents Soft materials are ubiquitous in technological applications that require deformability, for instance, in flexible, water-repellent coatings. However, the wetting properties of pre-strained soft materials are only beginning to be explored. Here we study the sliding dynamics of droplets on pre-strained soft silicone gels, both in tension and in compression. Intriguingly, in compression we find a non-monotonic strain dependence of the sliding speed: mild compressions decelerate the droplets, but stronger compressions lead again to faster droplet motion. Upon further compression, creases nucleate under the droplets until finally, the entire surface undergoes the creasing instability, causing a ``run-and-stop" motion. We quantitatively elucidate the speed modification for moderate pre-strains by incremental viscoelasticity, while the acceleration for larger pre-strains turns out to be linked to the solid pressure, presumably through a lubrication effect of expelled oligomers.
format Preprint
id arxiv_https___arxiv_org_abs_2411_03915
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Non-monotonic motion of sliding droplets on strained soft solids
Chao, Youchuang
Jeon, Hansol
Karpitschka, Stefan
Soft Condensed Matter
Soft materials are ubiquitous in technological applications that require deformability, for instance, in flexible, water-repellent coatings. However, the wetting properties of pre-strained soft materials are only beginning to be explored. Here we study the sliding dynamics of droplets on pre-strained soft silicone gels, both in tension and in compression. Intriguingly, in compression we find a non-monotonic strain dependence of the sliding speed: mild compressions decelerate the droplets, but stronger compressions lead again to faster droplet motion. Upon further compression, creases nucleate under the droplets until finally, the entire surface undergoes the creasing instability, causing a ``run-and-stop" motion. We quantitatively elucidate the speed modification for moderate pre-strains by incremental viscoelasticity, while the acceleration for larger pre-strains turns out to be linked to the solid pressure, presumably through a lubrication effect of expelled oligomers.
title Non-monotonic motion of sliding droplets on strained soft solids
topic Soft Condensed Matter
url https://arxiv.org/abs/2411.03915