Contact angle hysteresis origins: Investigation on super-omniphobic surfaces
Contact angle hysteresis origins: Investigation on super-omniphobic surfaces
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DOI：
10.1039/c1sm05832k
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发表时间：
2011-01-01
期刊：
影响因子：
3.4
通讯作者：
Senez, Vincent
中科院分区：
文献类型：
--
作者：
Dufour, Renaud;Harnois, Maxime;Senez, Vincent
研究了PDMS-Si_3 N_4微结构组成的粘性和柔性超疏水表面上液滴的接触角滞后现象。到目前为止，广泛的研究一直集中在滞后和表面性质，如粗糙度或缺陷密度之间的关系。然而，很少有人注意到滞后相对于液体表面张力的依赖性。在这项工作中，前进和后退的表观接触角测量表面上显示4个不同的缺陷密度与10水-乙醇混合物（表面能范围从72到21.7 mN m（-1））。虽然前进角被发现是恒定的，无论缺陷密度和液体表面能，后退角表现出更复杂的变化。令人惊讶的是，我们注意到在低表面能下该后退角的饱和。为了解释这一现象，我们从微毛细管桥形成和断裂的角度来解决后退接触线变形。该模型得到了局部变形的精细SEM观察的支持，并提供了一个新的视角来解释饱和现象的潜在机制。
Contact angle hysteresis of liquid droplets is investigated on sticky and flexible super-omniphobic surfaces made up of PDMS-Si3N4 microstructures. Up to now, extensive studies have been focusing on the relation between hysteresis and surface properties such as roughness or defect density. However, little attention has been paid to the dependence of hysteresis with respect to the liquid surface tension. In this work, advancing and receding apparent contact angles are measured on surfaces displaying 4 different defect densities with 10 water-ethanol mixtures (surface energy ranging from 72 to 21.7 mN m(-1)). While advancing angles are found to be constant whatever the defect density and the liquid surface energy, receding angles exhibit more complex variations. Surprisingly, we noticed a saturation of this receding angle at low surface energy. In order to explain this phenomenon, we address the receding contact line distortion from the point of view of micro capillary bridges formation and breakage. The model is supported by fine SEM observation of the local deformation and offers a new perspective to explain the underlying mechanism of the saturation phenomenon.