论文标题
外部张力对弹性板润湿的影响
Effect of external tension on the wetting of an elastic sheet
论文作者
论文摘要
对弹性毛细血管现象的最新研究引发了人们对经典年轻拉普拉斯 - 杜普雷(YLD)问题的基本变体的兴趣:液态滴和较薄的低弯曲刚度固体薄板之间的毛细血管相互作用。在这里,我们考虑了一个二维模型,该模型承担外部拉伸负荷,滴剂的特征是定义明确的Young接触角$θ_y$。使用数值,变异和渐近技术的组合,我们讨论润湿与所施加张力的函数。我们发现,对于$ 0 <θ_y<π/2 $的可润湿表面,由于表的变形,与需要$θ_y= 0 $的刚性基板相比,由于表的变形,因此可以在关键的施加张力下进行完整润湿。相反,对于非常巨大的施加紧张,板变得平坦,经典的部分润湿情况被恢复。在中间紧张局势时,薄板中形成了一个囊泡,该囊泡包围了大多数流体,我们在小弯曲刚度的极限下对这种润湿状态提供了准确的渐近描述。我们表明,弯曲刚度多么小,会影响囊泡的整个形状。发现了涉及部分润湿和``囊泡''溶液的丰富分叉图。对于适度小的弯曲刚度,部分润湿可以与囊泡溶液和完全润湿共存。最后,我们确定了与张力有关的弯曲毛细管长度,$λ_\ text {bc} $,发现滴的形状由比率$ a/λ_\ text {bc}^2 $确定,其中$ a $是滴头的区域。
Recent studies of elasto-capillary phenomena have triggered interest in a basic variant of the classical Young-Laplace-Dupré (YLD) problem: The capillary interaction between a liquid drop and a thin solid sheet of low bending stiffness. Here, we consider a two-dimensional model where the sheet is subjected to an external tensile load and the drop is characterized by a well-defined Young's contact angle $θ_Y$. Using a combination of numerical, variational, and asymptotic techniques, we discuss wetting as a function of the applied tension. We find that, for wettable surfaces with $0<θ_Y<π/2$, complete wetting is possible below a critical applied tension thanks to the deformation of the sheet in contrast with rigid substrates requiring $θ_Y=0$. Conversely, for very large applied tensions, the sheet becomes flat and the classical YLD situation of partial wetting is recovered. At intermediate tensions, a vesicle forms in the sheet, which encloses most of the fluid and we provide an accurate asymptotic description of this wetting state in the limit of small bending stiffness. We show that bending stiffness, however small, affects the entire shape of the vesicle. Rich bifurcation diagrams involving partial wetting and ``vesicle'' solution are found. For moderately small bending stiffnesses, partial wetting can coexist both with the vesicle solution and complete wetting. Finally, we identify a tension-dependent bendo-capillary length, $λ_\text{BC}$, and find that the shape of the drop is determined by the ratio $A/λ_\text{BC}^2$, where $A$ is the area of the drop.