The impact dynamics of a solution drop of Triton X-100 impinging on a paraffin film was studied, specifically to develop a new method for evaluating the in situ surface dilational rate, λ. The drop images (side and top views) during the impingement process were sequentially digitized and used to calculate the interfacial areas of the liquid-air and liquid-solid interfaces. The data of interfacial area were then used to calculate the relaxation of λ. The surface dilational rate showed a strong oscillation at the beginning of the drop impact. It oscillated from 0 down to −390/s, up to 290/s, and then down to −200/s. This surface dilational rate is far above 2.4/s, which is the lower limit of λ for an expanding pendant bubble in a Triton X-100 solution with an isolated air-liquid surface (Lin et al., 2017). A simple but useful theoretical framework is given for the calculation of the dynamic surface dilational rate, surface concentration and surface tension of an impinging drop of surfactant solution.

研究了Triton X-100溶液滴撞击石蜡膜的冲击动力学，特别是开发了一种评估原位的新方法表面膨胀率λ。撞击过程中的液滴图像（侧视图和俯视图）被顺序数字化，并用于计算液-气和液-固界面的界面面积。然后将界面面积的数据用于计算λ的弛豫。在跌落冲击开始时，表面膨胀率显示出强烈的振荡。它从0下降到-390 / s，上升到290 / s，然后下降到-200 / s。该表面膨胀率远高于2.4 / s，这是在具有孤立气液表面的Triton X-100溶液中膨胀悬垂气泡的λ下限（Lin等人，2017）。给出了一个简单但有用的理论框架来计算表面活性剂溶液撞击液滴的动态表面膨胀率，表面浓度和表面张力。