Laboratoire Charles Coulomb, UMR 5221, Université Montpellier 2 and CNRS, Place Eugène Bataillon, F-34095 Montpellier Cedex, France.
Phys Rev Lett. 2013 Sep 13;111(11):114301. doi: 10.1103/PhysRevLett.111.114301. Epub 2013 Sep 10.
Under the effect of surface tension, a blob of liquid adopts a spherical shape when immersed in another fluid. We demonstrate experimentally that soft, centimeter-size elastic solids can exhibit a similar behavior: when immersed into a liquid, a gel having a low elastic modulus undergoes large, reversible deformations. We analyze three fundamental types of deformations of a slender elastic solid driven by surface stress, depending on the shape of its cross section: a circular elastic cylinder shortens in the longitudinal direction and stretches transversally; the sharp edges of a square based prism get rounded off as its cross sections tend to become circular; and a slender, triangular based prism bends. These experimental results are compared to analysis and nonlinear simulations of neo-Hookean solids deformed by surface tension and are found to be in good agreement with each other.
在表面张力的作用下，浸入另一种液体中的液滴会呈现出球形。我们通过实验证明，柔软的厘米级弹性固体也可以表现出类似的行为：当浸入液体中时，弹性模量较低的凝胶会发生大的、可逆的变形。我们分析了表面应力驱动下三种基本类型的细长弹性固体变形，这取决于其横截面的形状：圆形弹性圆柱体在纵向缩短并横向拉伸；方形基底棱柱的尖锐边缘变圆，因为其横截面趋于变成圆形；以及一个细长的、三角形基底的棱柱弯曲。这些实验结果与受表面张力变形的新胡克固体的分析和非线性模拟进行了比较，发现它们之间具有很好的一致性。
