title: Vapor and Gas-Bubble Growth Dynamics around Laser-Irradiated, Water-Immersed Plasmonic Nanoparticles.
abstract: Microbubbles produced by exposing water-immersed metallic nanoparticles to resonant light play an important role in emerging and efficient plasmonic-enhanced processes for catalytic conversion, solar energy harvesting, biomedical imaging, and cancer therapy. How do these bubbles form, and what is their gas composition? In this paper, the growth dynamics of nucleating bubbles around laser-irradiated, water-immersed Au plasmonic nanoparticles are studied to determine the exact origin of the occurrence and growth of these bubbles. The microbubbles' contact angle, footprint diameter, and radius of curvature were measured in air-equilibrated water (AEW) and degassed water (DGW) with fast imaging. Our experimental data reveals that the growth dynamics can be divided into two regimes: an initial bubble nucleation phase (regime I, < 10 ms) and, subsequently a bubble growth phase (regime II). The explosive growth in regime I is identical for AEW and DGW due to the vaporization of water. However, the slower growth in regime II is distinctly different for AEW and DGW, which is attributed to the uptake of dissolved gas expelled from the water around the hot nanoparticle. Our scaling analysis reveals that the bubble radius scales with time as R(t) ∝ t1/6for both AEW and DGW in the initial regime I, whereas in the later regime II it scales as R(t) ∝ t1/3for AEW and is constant for perfectly degassed water. These scaling relations are consistent with the experiments.
authors.affiliation: Robotics Institute, School of Mechanical Engineering and Automation, Beihang University , Beijing 100191, P.R. China.
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Wang
authors.forename: Mikhail E
authors.initials: ME
authors.lastname: Zaytsev
authors.affiliation: MESA+ Institute for Nanotechnology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente , Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
authors.forename: Hai Le
authors.initials: HL
authors.lastname: The
authors.affiliation: MESA+ Institute for Nanotechnology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente , Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
authors.forename: Jan C T
authors.initials: JC
authors.lastname: Eijkel
authors.forename: Harold J W
authors.initials: HJ
authors.lastname: Zandvliet
authors.affiliation: Soft Matter and Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia.
authors.forename: Xuehua
authors.identifier: 0000-0001-6093-5324
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization , 37077 Goettingen, Germany.
authors.forename: Detlef
authors.identifier: 0000-0003-4138-2255
authors.initials: D
authors.lastname: Lohse
keywords: bubbles; dissolved gas; nanoparticles; plasmonics; vapor