Léopoldès J, Bucknall D G
Department of Materials, Oxford University, Oxford OX1 3PH, UK.
J Phys Chem B. 2005 May 12;109(18):8973-7. doi: 10.1021/jp0508094.
When a droplet of fluid is deposited on a surface with chemical and/or topological patterns, its static shape is highly dependent on the 2D distribution of the patterns. In the case of chemical stripes, three distinct spreading regimes have been observed as a function of wettability contrast between the two kind of stripes. For low wettability contrast, the droplet spreads with the same [corrected] velocity normal and parallel to the stripes [corrected] and the macroscopic contact angle is close to Cassie's contact angle. When the wettability contrast is intermediate/high, the resulting shape of the droplets is elongated. In the intermediate wettability contrast regime, an ideal situation shows stick and slip behavior of the contact line, during which the contact line jumps from one stripe to another. For a high wettability contrast, the confinement of the fluid between two chemical stripes leads to a 2D spreading.
当一滴流体沉积在具有化学和/或拓扑图案的表面上时，其静态形状高度依赖于图案的二维分布。对于化学条纹的情况，根据两种条纹之间的润湿性对比度，观察到三种不同的铺展状态。对于低润湿性对比度，液滴在垂直和平行于条纹方向上以相同的[校正后]速度铺展，宏观接触角接近卡西接触角。当润湿性对比度为中等/高时，液滴最终的形状会拉长。在中等润湿性对比度状态下，理想情况是接触线呈现粘滑行为，在此期间接触线从一条条纹跳到另一条条纹。对于高润湿性对比度，两种化学条纹之间流体的限制会导致二维铺展。
