Barakat Joseph M, Squires Todd M
Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States.
Langmuir. 2022 Jan 25;38(3):1099-1105. doi: 10.1021/acs.langmuir.1c02709. Epub 2022 Jan 11.
Heterogeneous fluid interfaces often include two-dimensional solid domains that mechanically respond to changes in interfacial curvature. While this response is well-characterized for rigid inclusions, the influence of solid-like elasticity remains essentially unexplored. Here, we show that an initially flat, elastic inclusion embedded in a curved, fluid interface will exhibit qualitatively distinct behavior depending on its size and stiffness. Small, stiff inclusions are limited by bending and experience forces directed up gradients of Gaussian curvature, in keeping with prior findings for rigid discoids. By contrast, larger and softer inclusions are driven down gradients of squared Gaussian curvature in order to minimize the elastic penalty for stretching. Our calculations of the force on a solid inclusion are shown to collapse onto a universal curve spanning the bending- and stretching-limited regimes. From these results, we make predictions for the curvature-directed motion of deformable solids embedded within a model interface of variable Gaussian curvature.
非均匀流体界面通常包含二维固体区域，这些区域会对界面曲率的变化产生机械响应。虽然这种响应对于刚性夹杂物已经有了很好的表征，但类固体弹性的影响基本上仍未被探索。在这里，我们表明，嵌入弯曲流体界面中的初始平坦弹性夹杂物，根据其尺寸和刚度将表现出定性不同的行为。小的、刚性的夹杂物受弯曲限制，并受到指向高斯曲率梯度向上的力，这与之前关于刚性盘状体的研究结果一致。相比之下，更大、更软的夹杂物会沿着平方高斯曲率的梯度向下移动，以尽量减少拉伸的弹性惩罚。我们对固体夹杂物上力的计算结果显示，它们可以归结为一条跨越弯曲和拉伸限制区域的通用曲线。基于这些结果，我们对嵌入可变高斯曲率模型界面内的可变形固体的曲率导向运动做出了预测。
