Jet drops resulting from bubble bursting at a liquid surface play a key role in various mass transfer processes across the interface, including sea spray aerosol generation and pathogen transmission. However, the impact of structurally compound interfaces, characterized by complex surface rheology introduced by surface-active contaminants, on the jet drop ejection still remains unclear. Here, we experimentally investigate the influence of surface viscoelasticity on the size and velocity of the top jet drops from surface bubble bursting, examining both pure protein and mixed protein–surfactant solutions. We document that for bubble bursting at a pure-protein-laden surface where surface elasticity dominates, the increase in E_c, i.e. the interfacial elastocapillary number as the ratio between the effects of interfacial elasticity and capillarity, efficiently increases the radius and decreases the velocity of the top jet drop, ultimately inhibiting the jet drop ejection. On the other hand, considering the mixed protein–surfactant solution, we show that the top jet drop radius and velocity exhibit a different variation trend with E_c, which is attributed to the additional dissipation on the capillary waves as well as the retardation and resistance on the converging flow for jet formation from surface viscoelasticity. Our work may advance the understanding of bubble bursting dynamics at contaminated liquid surfaces and shed light on the potential influence of surface viscoelasticity on the generation of bubble bursting aerosols.

中文翻译：

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表面粘弹性对气泡破裂产生的顶部喷射液滴的影响

液体表面气泡破裂产生的喷射液滴在跨界面的各种传质过程中发挥着关键作用，包括海喷雾气溶胶的产生和病原体传播。然而，结构复合界面（其特征是表面活性污染物引入的复杂表面流变学）对喷射液滴喷射的影响仍不清楚。在这里，我们通过实验研究了表面粘弹性对表面气泡破裂产生的顶部喷射液滴的尺寸和速度的影响，检查了纯蛋白质和混合蛋白质-表面活性剂溶液。我们记录了，对于表面弹性占主导地位的纯蛋白质表面的气泡破裂，E _c的增加，即界面弹性毛细管数作为界面弹性和毛细管作用之间的比率，有效地增加了半径并降低了速度顶部喷射液滴，最终抑制喷射液滴喷射。另一方面，考虑到混合的蛋白质-表面活性剂溶液，我们发现顶部射流液滴半径和速度随E _c表现出不同的变化趋势，这归因于毛细波的额外耗散以及延迟和阻力关于表面粘弹性射流形成的会聚流。我们的工作可能会增进对受污染液体表面气泡破裂动力学的理解，并揭示表面粘弹性对气泡破裂气溶胶产生的潜在影响。