Removal of surface-attached micro- and nanobubbles by ultrasonic cavitation in microfluidics

• DOI: 10.1016/j.ultsonch.2024.107011
• Publication Date: 2024-08-03T16:20:13Z
• Authors: Zibo Ren; Peng Xu; Huan Han; Claus-Dieter Ohl; Zhigang Zuo; Shuhong Liu
• Keywords: Microchannel; Acoustic streaming; Merge (version control)

Surface-attached micro- and nanobubbles are known for their resistance to external forces. This study experimentally theoretically investigates response strong ultrasonic fields. with contact radii from 2 μm 20 generated in a microchannel exposed ultrasound through vibrating glass substrate. At driving frequency over 200 kHz up MHz tested, no significant the is observed. By contrast, at 100 kHz–200 kHz, cavitation bubbles appear migrate toward surface nanobubbles. Then merge bubbles, detach substrate, become free gaseous nuclei susceptible further cavitation. Notably, removal process leaves observable residue. Theoretical analysis suggests that directional migration of driven by mutual acoustic radiation work demonstrates fields can effectively remove nanobubbles, transforming them into nuclei.