雾滴体积和测量时间与雾滴接触角的关系

农药喷雾质量直接关系到药效的发挥,喷雾液滴与靶标的接触角可以用来表征喷雾质量的好坏,并可说明喷洒液的表面张力与靶标的表面张力是否匹配。针对喷雾液滴在靶标上接触角测量的重现性不佳等问题,以玻璃和石蜡模拟靶标表面,研究了去离子水在亲水和疏水靶标表面上液滴体积(重力)和测量时间对接触角测量的影响,结果表明:液滴体积越大接触角越小,这种趋势在亲水表面比疏水表面上更突出,测量时体积可分别选择在0.5~1μl和1~5μl;液滴滴下30~50 s后与固体表面基本达到平衡,对接触角测量的准确度影响较小。

Studies on Relation of Droplet Contact Angle to Droplet Volume and Measuring Time

Spraying quality is directly related to the efficiency of pesticide action.Contact angle(CA) between spraying droplet and target can be used to describe spraying quality and illustrate whether suface tention of spraying dilution is matched with surface tension(ST) of target.In order to resolve the repeatability of contact angle measurement,the factors such as droplet volume,measure time,hydrophilic and hydrophobic targets were studied by using deionized water on glass and paraffin surface.It is shown that the larger the droplet volume is the smaller the CA is which is more remarkable on hydrophilic surface than hydrophobic one.If the volumes are selected in 0.5-1μl and 1-5μl,the droplets will be balanced on the solid surfaces in 30-50s.