SEPARATION OF SMALL BUBBLE FROM GAS FLOW INJECTED INTO TURBULENT BOUNDARY LAYER

液滴在斜板上的滑动角一直没有精确的理论预测。基于宏观润湿行为，从液滴所受重力和表面张力之间的力平衡出发，探讨了计算液滴滑动角的理论模型。三种试验液体与固体板的每种组合的滑动角测量结果与实验结果吻合得很好。用近似理论计算了液滴在倾斜平板上的三维形貌，结果与照相测量的形貌吻合较好，为了尽可能简单地检测自组装膜上的微观缺陷，本文讨论了利用上述滑动角检测自组装膜上微观缺陷的可能性。采用浸渍法在硅片上制备了四种不同浸渍时间的自组装膜测试板。首先，用作者提出的方法对自组装膜表面的接触角进行了实验测量。结果表明，均匀的标准膜与分子有序缺陷的膜相比，接触角滞后相差1 <$2度。这表明宏观润湿特性取决于固体表面的微观缺陷。接下来，对于体积为1 μ l的液滴测量SAM上的滑动角。标准膜与其他缺陷膜的滑动角相差6 °，远大于上述接触角滞后差。通过滑动角的测量可以很容易地检测出自组装膜上的缺陷。

There has been no exact theory to predict the sliding angle of liquid droplet on the inclined plate. In this study, based on the macroscopic wetting behavior , the theoretical model to calculate the sliding angle was discussed from the force balance between the gravitational force and the surface tension acting on the droplet. The results of sliding angles agreed very well with those of experiments for each combination between three kinds of test liquids and solid plates. The profile of three dimensional liquid droplet on the inclined plate was obtained from an approximate theory and the results agreed well with measured profiles by photograph.In order to detect the microscopic defect on the Self Assembled Monolayers (SAMs) as simple as possible, we discussed the possibility of the method by use of sliding angles stated above. The test plates of SAMs on the silicon wafer were made by the immersion method for four kinds of immersion time. First, the contact angles on the SAMs plates were measured experimentally by the method proposed by the authors. The results showed that there appeared the difference of contact angle hysteresis 1〜2degrees between homogeneous standard film and other films with defect of molecular order. This indicates that the macroscopic wetting characteristics is dependent on the microscopic defect on the solid surface. Next, the sliding angles on SAMs were measured for the droplet with volume of1μ1. The difference of sliding angle between standard film and other films with defect were 6 degrees, which is much larger than the difference of contact angle hysteresis stated above. The defect on SAMs may be detected easily from the measurement of sliding angles.