Directional liquid wicking in regular arrays of triangular posts.
Directional liquid wicking in regular arrays of triangular posts.
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DOI：
10.1021/acs.langmuir.9b03032
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
Ban-Yang Liu;R. Seemann;Li-Jen Chen;M. Brinkmann
中科院分区：
文献类型：
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作者：
Ban-Yang Liu;R. Seemann;Li-Jen Chen;M. Brinkmann
通过实验和数值能量最小化方法研究了润湿液体在均匀三角形截面柱微图案中的芯吸作用。为了测试定向芯吸，我们使用标准光刻工艺制造了具有线分数和纵横比的各种组合的柱的规则阵列。与数值能量最小化的液体膜形态，我们发现自发芯吸的实验中只为线分数和纵横比的均匀的液体膜代表的状态最低的界面自由能，并在我们的数值能量最小化没有本地能量最小值可以检测到。数值结果进一步表明，末端弯月面的某种形态的稳定性控制相对于三角形柱的取向的芯吸方向。所观察到的自发芯吸相对于弯月面取向的选择性可以被利用来构建用于部分润湿液体的微流体整流器。
Wicking of wetting liquids into micro-patterns of posts with homogeneous triangular cross-section is studied in experiments and by numerical energy minimizations. To test for directional wicking we fabricated regular arrays of posts with various combinations of line fractions and aspect ratios using standard photolithography processes. In agreement with numerical energy minimizations of the liquid film morphology, we find spontaneous wicking in the experiments only for line fractions and aspect ratios where the homogeneous liquid film represents the state of lowest interfacial free energy and where no local energy minimum could be detected in our numerical energy minimizations. The numerical results further demonstrate that the stability of a certain morphology of the terminal meniscus controls the direction of wicking relative to the orientation of the triangular posts. The observed selectivity of spontaneous wicking in respect to the meniscus orientation can be exploited to build a micro-fluidic rectifier for partially wetting liquids.