Thermocapillary motion of a liquid drop on a horizontal solid surface
Thermocapillary motion of a liquid drop on a horizontal solid surface
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DOI：
10.1021/la7036839
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发表时间：
2008-05-06
期刊：
影响因子：
3.9
通讯作者：
Subramanian, R. Shankar
中科院分区：
文献类型：
--
作者：
Pratap, Vikram;Moumen, Nadjoua;Subramanian, R. Shankar
实验研究了正癸烷液滴在水平聚二甲基硅氧烷（PDMS）涂层玻璃表面上的温度梯度运动，并利用润滑近似理论描述了球帽状液滴在水平固体表面上的热毛细运动。在实验中改变液滴的大小和施加的温度梯度，并将测得的液滴速度与模型的预测进行比较。理论模型正确地预测了液滴速度随液滴尺寸和温度梯度的变化规律，尽管实际速度比预测的要小。接触角滞后的影响，这导致一个临界滴尺寸低于该滴不移动，被发现是最小的。与以前的研究不同（Chen，J. Z.; Troian，S. M.; Darhuber，A.一、瓦格纳，S. J.Appl.Phys.2005，97，014906; Brzoska，J. B.; Brochard-Wyart，F.; Rondelez，F. Langmuir 1993，9，2220），该小的临界液滴尺寸似乎与所施加的温度梯度无关。结果还提出了上的变形的移动液滴的接触线的纵横比的形式，并与温度差横跨的足迹的液滴和毛细管数。
The motion of drops of decane on horizontal poly(dimethylsiloxane) (PDMS)-coated glass surfaces resulting from a temperature gradient on the surface is studied experimentally, and a theoretical description of the thermocapillary motion of spherical-cap drops on a horizontal solid surface obtained using the lubrication approximation also is presented. The drop size and the applied temperature gradient are varied in the experiments, and the measured velocities of the drops are compared with predictions from the model. The scalings of the velocity with drop size and with the applied temperature gradient are predicted correctly by the theoretical model, even though the actual velocities are smaller than those predicted. The influence of contact angle hysteresis, which leads to a critical drop size below which drops do not move, is found to be minimal. Unlike in previous studies (Chen, J. Z.; Troian, S. M.; Darhuber, A. A.; Wagner, S. J. Appl. Phys. 2005, 97, 014906; Brzoska, J. B.; Brochard-Wyart, F.; Rondelez, F. Langmuir 1993, 9, 2220), this small critical drop size appears to be independent of the applied temperature gradient. Results also are presented on the deformation of the contact lines of the moving drops in the form of an aspect ratio, and correlated with the temperature difference across the footprints of the drops and the capillary number.