Electric field induced microstructures in thin films on physicochemically heterogeneous and patterned substrates.
Electric field induced microstructures in thin films on physicochemically heterogeneous and patterned substrates.
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DOI：
10.1063/1.3400653
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发表时间：
2010-05
期刊：
影响因子：
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通讯作者：
Samanvaya Srivastava;P. D. S. Reddy;Cindy Wang;D. Bandyopadhyay;Ashutosh Sharma
中科院分区：
文献类型：
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作者：
Samanvaya Srivastava;P. D. S. Reddy;Cindy Wang;D. Bandyopadhyay;Ashutosh Sharma
我们通过非线性模拟研究位于地形或化学图案化基底上的粘性薄膜中电场诱导的图案形成。薄膜微结构可以在参数窗口内与衬底图案对准，其中场引起的不稳定性的旋节线长度尺度接近衬底周期性。我们系统地研究了当（i）基板图案周期在恒定的膜厚度下变化和（ii）膜厚度在恒定的基板周期下变化时，膜形态和顺序的变化。模拟显示了当基板形貌从突起变为空腔时两种不同的演化途径。孤立的衬底缺陷产生与周期性图案化衬底上的结构不同的局部有序波纹状结构。在后一种情况下，薄膜形态由图案周期性和不稳定性长度尺度之间的竞争决定。将薄膜形态与下面的基板图案相关联对于场诱导图案化和界面间图案转移的鲁棒性（例如，印刷在基板上的信息的编码-解码）具有影响。
We study by nonlinear simulations the electric field induced pattern formation in a thin viscous film resting on a topographically or chemically patterned substrate. The thin film microstructures can be aligned to the substrate patterns within a window of parameters where the spinodal length scale of the field induced instability is close to the substrate periodicity. We investigate systematically the change in the film morphology and order when (i) the substrate pattern periodicity is varied at a constant film thickness and (ii) the film thickness is varied at a constant substrate periodicity. Simulations show two distinct pathway of evolution when the substrate-topography changes from protrusions to cavities. The isolated substrate defects generate locally ordered ripplelike structures distinct from the structures on a periodically patterned substrate. In the latter case, film morphology is governed by a competition between the pattern periodicity and the length scale of instability. Relating the thin film morphologies to the underlying substrate pattern has implications for field induced patterning and robustness of inter-interface pattern transfer, e.g., coding-decoding of information printed on a substrate.