Moving contact-line mobility measured
Moving contact-line mobility measured
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DOI：
10.1017/jfm.2018.105
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发表时间：
2018-03-01
影响因子：
3.7
通讯作者：
Steen, Paul H.
中科院分区：
文献类型：
--
作者：
Xia, Yi;Steen, Paul H.
接触线迁移率通过将接触角Δ α与接触线速度U-CL相关联来表征液体润湿或不润湿固体载体的速度。在液体快速移动通过固体时，接触角随接触线速度动态变化。粘滑区以外的速度是本文实验的重点。对于这些速度，液体惯性和表面张力竞争，而阻尼较弱。迁移率参数M根据经验定义为Δ α和U-CL之间的比例，当它存在时，M Δ α = U-CL。我们发现了M的存在，并测量了它。实验方法是通过液滴支撑点的平动来驱动液滴的接触线。测量了接触角、位移和接触线速度。为了揭示粘滑的移动性，将传统的Delta alpha对U-CL的图通过位移重新缩放重新映射为新的图。这个新的图表揭示了一个区域，其中1 Δ α与U-CL成比例，斜率产生迁移率M。报道的实验方法介绍了循环动态接触角测角仪。的概念和方法的测角仪说明与数据映射的lowhysteresis非润湿基板上的水。
Contact-line mobility characterizes how fast a liquid can wet or unwet a solid support by relating the contact angle Delta alpha to the contact-line speed U-CL. The contact angle changes dynamically with contact-line speeds during rapid movement of liquid across a solid. Speeds beyond the region of stick-slip are the focus of this experimental paper. For these speeds, liquid inertia and surface tension compete while damping is weak. The mobility parameter M is defined empirically as the proportionality, when it exists, between Delta alpha and U-CL, M Delta alpha = U-CL. We discover that M exists and measure it. The experimental approach is to drive the contact line of a sessile drop by a planenormal oscillation of the drop's support. Contact angles, displacements and speeds of the contact line are measured. To unmask the mobility away from stick-slip, the diagram of Delta alpha against U-CL, the traditional diagram, is remapped to a new diagram by rescaling with displacement. This new diagram reveals a regime where 1 Delta alpha is proportional to U-CL and the slope yields the mobility M. The experimental approach reported introduces the cyclically dynamic contact angle goniometer. The concept and method of the goniometer are illustrated with data mappings for water on a lowhysteresis non-wetting substrate.