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arXiv · 1312.7423

Shedding new light on the mystery of wetting on soft solids

Su Ji Park·Byung Mook Weon·Ji San Lee·Junho Lee·Jinkyung Kim·Jung Ho Je
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Abstract

One of the most questionable issues in wetting is the vertical force balance that is excluded in Young's law. On soft deformable solids, such as biotic materials and synthetic polymers, the vertical force of liquid leads to a microscopic protrusion of the contact line, i.e. a "wetting ridge". The wetting principle that determines the geometry of the ridge-tip is at the heart of the issues over the past half century. Here, we reveal a universal wetting principle by directly visualizing ridge-tips with high spatio-temporal resolution using x-ray microscopy. We find that the tip-geometry is asymmetric and bent, and invariant during ridge growth or by surface softness. This singular geometry is explained by linking the macroscopic and microscopic contact angles to Young's and Neumann's laws, respectively. Our dual-scale model would be applicable to a general framework in wetting and give new clues to various issues in cell-substrate interaction and elasto-capillary problems.

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Su Ji Park, Byung Mook Weon, Ji San Lee, Junho Lee, Jinkyung Kim, Jung Ho Je. 2013-12-28. Shedding new light on the mystery of wetting on soft solids. https://arxiv.org/abs/1312.7423

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