Self-organized structures in thin liquid films on chemically heterogeneous substrates: Effect of antagonistic short and long range interactions
Self-organized structures in thin liquid films on chemically heterogeneous substrates: Effect of antagonistic short and long range interactions
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化学异质基质上薄膜中的自组织结构：拮抗的短程和长程相互作用的影响
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发表时间：
2001
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通讯作者：
Ashutosh Sharma
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作者：
M. Zope;K. Kargupta;Ashutosh Sharma
基于非线性模拟方法，研究了在长程货车德瓦耳斯吸引和短程软排斥作用下，化学非均匀基底上薄液膜自发去湿过程中的表面不稳定性、动力学和形貌.非均匀性的去湿特征与均匀表面上的旋节线去湿形成了鲜明的对比。在化学不均匀性的存在下，不稳定性是由导致微尺度润湿性对比的分子间相互作用的梯度引起的。不稳定性的时间尺度可以大大小于亚稳时间尺度，特别是对于接近临界厚度的较薄的膜，并且它与由异质性引起的电势差成反比。在非常小的长度尺度上，异质结甚至可以使旋节稳定的膜不稳定。局部有序的结构（液滴和孔）周围的异质性产生的“城堡护城河”，“涟漪”和“花”l…
Surface instability, dynamics, and morphology in spontaneous dewetting of a thin liquid film on a chemically heterogeneous substrate are studied based on nonlinear simulations for a system subjected to a long range van der Waals attraction and soft short-range repulsion. Characteristics of dewetting by a heterogeneity are clearly contrasted with the spinodal dewetting on a homogeneous surface. In the presence of a chemical heterogeneity, the instability is engendered by the gradient of intermolecular interactions that lead to a microscale wettability contrast. The time scale of instability can be substantially less than the spinodal time scale, especially for thinner films close to the critical thickness, and it varies inversely with the potential difference induced by the heterogeneity. Heterogeneity, on a very small length scale, can even destabilize a spinodally stable film. A local ordering of the structure (droplets and holes) around the heterogeneity produces “castle-moat,” “ripples,” and “flower” l...