The control of the morphology of desiccation cracks is fascinating not only from the application point of view but also from the rich physics behind it. Here, we present a seemingly simple method to tailor the morphology of desiccation cracks by exploitation of the combined effect of particle shape anisotropy and the shape of the confining boundary. This allows us to make circular, square, and triangular-shaped desiccation cracks in the vicinity of the confining boundaries. As the colloidal dispersion dries in confined wells, a drying front appears at the center of the well. With further evaporation, the drying front recedes toward the boundary from the center of the well. We show that the temporal evolution of the drying front is strongly influenced by the shape of the well. Subsequently, desiccation cracks appear in the penultimate stage of drying, and the morphology of the cracks is governed by the shape of the drying front and hence by the shape of the wells. The spatial evolution of the crack pattern is quantified by estimation of the curvature of the cracks, which suggests that the influence of the confining boundary on crack formation is long-ranged. However, the cracks in the dried deposit consisting of spherical particles remain unaffected by the shape of the well, and the cracks are always radial. We establish a one-to-one correspondence between the shape of the drying front and the morphology of the crack pattern in the final dried deposit of ellipsoids.

中文翻译：

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围压边界形状和颗粒形状各向异性对干燥裂纹形貌的影响

干燥裂纹形态的控制不仅从应用的角度来看，而且从其背后丰富的物理学来看，都是令人着迷的。在这里，我们提出了一种看似简单的方法，通过利用颗粒形状各向异性和限制边界形状的组合效应来调整干燥裂缝的形态。这使我们能够在限制边界附近制作圆形、方形和三角形的干燥裂缝。随着胶体分散体在密闭井中干燥，干燥前沿出现在井的中心。随着进一步的蒸发，干燥前沿从井的中心向边界后退。我们表明，干燥前沿的时间演变受到井形状的强烈影响。随后，干燥裂缝出现在干燥的倒数第二阶段，裂缝的形态由干燥前沿的形状决定，因此也由井的形状决定。通过估计裂缝的曲率来量化裂缝模式的空间演变，这表明限制边界对裂缝形成的影响是长期的。然而，由球形颗粒组成的干燥沉积物中的裂缝不受井形的影响，裂缝始终呈放射状。我们在椭圆体的最终干燥沉积物中建立了干燥前沿的形状和裂纹图案的形态之间的一一对应关系。通过估计裂缝的曲率来量化裂缝模式的空间演变，这表明限制边界对裂缝形成的影响是长期的。然而，由球形颗粒组成的干燥沉积物中的裂缝不受井形的影响，裂缝始终呈放射状。我们在椭圆体的最终干燥沉积物中建立了干燥前沿的形状和裂纹图案的形态之间的一一对应关系。通过估计裂缝的曲率来量化裂缝模式的空间演变，这表明限制边界对裂缝形成的影响是长期的。然而，由球形颗粒组成的干燥沉积物中的裂缝不受井形的影响，裂缝始终呈放射状。我们在椭圆体的最终干燥沉积物中建立了干燥前沿的形状和裂纹图案的形态之间的一一对应关系。