Capillary Pressure and Contact Line Force on a Soft Solid
Abstract
The surface free energy, or surface tension, of a liquid interface gives rise to a pressure jump when the interface is curved. Here we show that a similar capillary pressure arises at the interface of soft solids. We present experimental evidence that immersion of a thin elastomeric wire into a liquid induces a substantial elastic compression due to the solid capillary pressure at the bottom. We quantitatively determine the effective surface tension from the elastic displacement field, and find a value comparable to the liquid-vapor surface tension. Most importantly, these results also reveal the way the liquid pulls on the solid close to the contact line: the capillary force is not oriented along the liquid-air interface, nor perpendicularly to the solid surface, as previously hypothesized, but towards the interior of the liquid.
Cite
@article{arxiv.1201.4268,
title = {Capillary Pressure and Contact Line Force on a Soft Solid},
author = {Antonin Marchand and Siddhartha Das and Jacco H. Snoeijer and Bruno Andreotti},
journal= {arXiv preprint arXiv:1201.4268},
year = {2015}
}