Desiccation crack patterns in drying laponite gel formed in an electrostatic field
Desiccation crack patterns in drying laponite gel formed in an electrostatic field
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DOI：
10.1016/j.clay.2007.05.005
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发表时间：
2008-04
影响因子：
5.6
通讯作者：
D. Mal;S. Sinha;T. Middya;S. Tarafdar
中科院分区：
文献类型：
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作者：
D. Mal;S. Sinha;T. Middya;S. Tarafdar
干燥裂缝在天然和合成粘土中形成有趣的图案。在水溶液中具有净负表面电荷的粘土片晶受到电场的影响。本文报道了在径向外电场中裂纹形成的观测结果。裂纹从任何一个正极开始呈放射状，无论是中心电极还是外部电极。没有磁场的相同几何形状不会产生典型的放射状图案。径向排列引起的场的不均匀性是一个关键因素，我们发现矩形几何中产生的均匀场没有任何明显的特征。薄膜的SEM图像显示，粘土纳米片的排列在有和没有外部场干燥的样品中有很大的不同。在没有电场的情况下，粒子线性排列，大概是沿着衬底上的缺陷沿着，但是电场破坏了这种排列，产生了均匀的无序排列。
Desiccation cracks form interesting patterns in natural and synthetic clays. Clay platelets, having a net negative surface charge in aqueous solution, are affected by an electric field. We report observation of cracks forming in a radial external electric field. The cracks start radially from whichever electrode is positive, whether it is the central or outer electrode. The same geometry without the field does not produce the characteristic radial pattern. The non-uniform nature of the field due to the radial arrangement is a crucial factor, we find that the uniform field produced in rectangular geometry does not show any distinctive feature. SEM images of the films show that the arrangement of the clay nano-platelets is quite different in samples dried with and without the external field. With no field, the particles are aligned linearly, presumably along defects on the substrate, but the electric field disrupts this alignment and produces a homogeneous disordered arrangement.