Krasovitski Boris, Marmur Abraham
Departments of Biomedical Engineering and Chemical Engineering, Technion-Israel Institute of Technology, 32000 Haifa, Israel.
Langmuir. 2005 Apr 26;21(9):3881-5. doi: 10.1021/la0474565.
The limiting inclination angle (slip angle), for which a two-dimensional water drop may be at equilibrium on a chemically heterogeneous surface, is exactly calculated for a variety of cases. The main conclusion is that, in the cases studied, the contact angles at the upper and lower contact line do not always simultaneously equal the receding and advancing contact angles, respectively. On a hydrophobic surface, the lowest contact angle (at the upper contact line) tends to be approximately equal to the receding contact angle, while the highest contact angle (at the lower contact line) may be much lower than the advancing contact angle. For hydrophilic surfaces, the opposite is true. These conclusions imply that the hysteresis range cannot in general be measured by analyzing the shape of a drop on an inclined plane. Also, the limiting inclination angle cannot in general be calculated from the classical equation based only on the advancing and receding contact angles.
对于各种情况，精确计算了二维水滴在化学异质表面上可能处于平衡状态时的极限倾斜角（滑移角）。主要结论是，在所研究的情况下，上下接触线处的接触角并不总是分别同时等于后退接触角和前进接触角。在疏水表面上，最低接触角（在上接触线处）往往近似等于后退接触角，而最高接触角（在下接触线处）可能远低于前进接触角。对于亲水表面，情况则相反。这些结论意味着，一般不能通过分析倾斜平面上液滴的形状来测量滞后范围。此外，一般不能仅根据前进接触角和后退接触角，从经典方程计算极限倾斜角。
