Distinct Jetting Dynamics of Contaminated Bubble Bursting and Their Role in Contaminant-Laden Aerosol Emission

When a bubble bursts at an air-liquid interface, the collapse of the bubble cavity associated with capillary wave converging generates an upward jet that can fragment into small droplets. Since these small droplets can remain suspended in the air as a key source of aerosols for water-to-air transport, this jetting phenomenon has been studied over decades due to its significance in a variety of topics, including flavor release from sparkling drinks, cloud-forming marine aerosols, and airborne transport of microplastic particles as well as respiratory pathogens. However, the effects of contaminants originating from diverse natural or industrial sources--such as immiscible impurities, surfactants, or proteins--on the bubble bursting jets remain largely unclear. In this talk, we explore some distinct features of jetting dynamics produced by bursting contaminated bubbles (e.g. oil-coated and protein-laden bubbles) 1-5. Through a combination of experiments, theory and numerical simulations, we provide a framework based on capillary wave propagation to rationalize our observations, considering the interplay of inertia, surface tension, viscosity, and/or interfacial rheology. The implications for bubble-mediated contaminant transmission are further discussed.

1 Z. Yang, B. Ji, J. Feng, Daughter oil droplet entrainment by oil-coated bubble bursting. J. Fluid Mech. 977, A10 (2023).
2 B. Ji, Z. Yang, Z. Wang, R. H. Ewoldt, J. Feng, Secondary bubble entrainment via primary bubble bursting at a viscoelastic surface. Phys. Rev. Lett. 131, 104002 (2023).
3 Z. Yang, B. Ji., J.T. Ault, J. Feng, Enhanced singular jet formation in oil-coated bubble bursting. Nat. Phys., 19, 884-890 (2024)
4 Z. Yang, J. Feng, Jet size prediction in multiphase compound bubble bursting, Phys. Rev. Lett. accepted

Jie Feng is an Assistant Professor in the Department of Mechanical Science & Engineering at the University of Illinois at Urbana-Champaign, directing the Fluids, Interfaces & Transport (FIT) laboratory. He received his B.S. from Tsinghua University and his Ph.D. in Mechanical & Aerospace Engineering from Princeton University. He completed his postdoctoral research in Chemical & Biological Engineering at Princeton University before joining the University of Illinois. The research of his group focuses on understanding microscale transport phenomena in complex fluids, with a particular emphasis on the dynamics of drops, bubbles, and vesicles. He aims to leverage these insights to address some of the challenging problems in energy, the environment, and healthcare, where complex fluid dynamics plays a central role. He was recognized as an Emerging Investigator by Soft Matter in 2023 and Nanoscale in 2024. His research is supported by the National Science Foundation, the American Chemical Society's Petroleum Research Fund, and industry.