When small particles (e.g., flour, pollen, etc.) come in contact with a liquid surface, they immediately disperse. The dispersion can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. This explosive-like dispersion is the consequence of capillary forces pulling particles into the interface causing them to accelerate to a relatively large velocity. The maximum velocity increases with decreasing particle size; for nanometer-sized particles (e.g., viruses and proteins), the velocity on an air-water interface can be as large as 47 m/s. We also show that particles oscillate at a relatively-high frequency about their floating equilibrium before coming to stop under viscous drag. The observed dispersion is a result of strong repulsive hydrodynamic forces that arise because of these oscillations.
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机译：当小颗粒（例如面粉，花粉等）与液体表面接触时，它们会立即分散。分散可能发生得如此之快，以至于呈现爆炸性，特别是对于流动性液体（如水）表面的小颗粒。这种爆炸性的分散是毛细作用力将颗粒拉入界面的结果，该作用使颗粒加速到相对较大的速度。最大速度随着粒径的减小而增加。对于纳米尺寸的粒子（例如病毒和蛋白质），空气-水界面的速度可高达47 m / s。我们还表明，粒子在它们的漂浮平衡附近以相对较高的频率振荡，然后在粘性阻力作用下停止。观察到的分散是由于这些振荡而产生的强烈排斥流体动力的结果。
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