Periodic bouncing of a plasmonic bubble in a binary liquid by competing solutal and thermal Marangoni forces

• Published in: Proceedings of the National Academy of Sciences - PNAS 2021-06, Vol.118 (23), p.1-7
• Main Authors: Diddens, Christian, Detert, Marvin, Zandvliet, Harold J. W., Lohse, Detlef
• Format: Article
• Language: English
• Subjects: Bouncing; Bubbles; Ethanol; Fluid dynamics; Fluid flow; Hydrodynamics; Laser beam heating; Nanoparticles; Nucleation; Phase transitions; Physical Sciences; Plasmonics; Substrates; Temperature gradients; Vaporization
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2103215118

The physicochemical hydrodynamics of bubbles and droplets out of equilibrium, in particular with phase transitions, display surprisingly rich and often counterintuitive phenomena. Here we experimentally and theoretically study the nucleation and early evolution of plasmonic bubbles in a binary liquid consisting of water and ethanol. Remarkably, the submillimeter plasmonic bubble is found to be periodically attracted to and repelled from the nanoparticle-decorated substrate, with frequencies of around a few kilohertz. We identify the competition between solutal and thermal Marangoni forces as the origin of the periodic bouncing. The former arises due to the selective vaporization of ethanol at the substrate’s side of the bubble, leading to a solutal Marangoni flow toward the hot substrate, which pushes the bubble away. The latter arises due to the temperature gradient across the bubble, leading to a thermal Marangoni flow away from the substrate, which sucks the bubble toward it. We study the dependence of the frequency of the bouncing phenomenon from the control parameters of the system, namely the ethanol fraction and the laser power for the plasmonic heating. Our findings can be generalized to boiling and electrolytically or catalytically generated bubbles in multicomponent liquids.