化学非光滑表面和几何粗糙表面的润湿性

Wettability of Chemical Unsmoothed Surfaces and Rough Surfaces

研究了弥散Al_2O_3粒子的尼龙1010基复合涂层和喷涂T8钢—浸渍聚有机硅氧烷的复合涂层两类化学非光滑表面及聚乙烯、聚苯乙烯、尼龙6、尼龙1010、T8钢、45钢和Al_2O_3粗糙表面的润湿性。导出了弥散球形粒子型化学非光滑表面上液体接触角与其组成相固有接触角关系的方程,该方程与尼龙1010—Al_2O_3粒子复合涂层表面接触角试验结果吻合良好。在尼龙1010基体中加入适量Al_2O_3粒子后,液体接触角未发生明显变化;T8钢喷涂层浸渍聚有机硅氧烷后,表面憎水性明显增强;材料的固有接触角越远离90°,表面粗糙性对接触角的影响越明显。

Surface wettability of soil-engaging components of terrain machines and tools influences their soil adhesion behaviour considerably. Hydrophobic materials have, in many situations, excellent property of reducing soil adhesion. Wetting behaviour of rough surfaces and chemical unsmoothed surfaces consisting of materials with high surface energy and with low surface energy is different from homogeneous and smooth surfaces.An equation of relationship between contact angles for a liquid on chemical unsmoothed surfaces formed by dispersing particles in the matrix of other materials and intrinsic contact angles of their components has been derived. For chemical unsmoothed surfaces dispersed with A12O3 particles in PA 1010 matrix, measured values of their contact angles fit well with the values calculated by the equation. The effect of a certain content of A12O3 particles on contact angles for liquid on the chemical unsmoothed surfaces formed by dispersing A12O3 particles in the matrix of PA1010 is a little. Hydrophobicity of steel T8 - polysiloxane chemical unsmoothed surfaces is, considerably, enhanced in comparison with steel T8.Wettability of rough surfaces of steel, Al2O3 and polymers varies due to surface irregularity and the extent of change of the contact angles depends upon their inherent wettability, that is, wetting behaviour of smooth surfaces of these materials. The greater the difference between their intrinsic contact angles and ninety degrees, the greater the effect of surface roughness on contact angles is.