Nanoscale Investigation
into Dynamics of Thin Liquid
Films during Bouncing and Attachment of Rising Air Bubbles on Hydrophilic
and Hydrophobic Surfaces
posted on 2023-11-30, 17:34authored byFatemeh Hamidzadeh, Kaiwu Huang, Xinyu Ye, Lei Pan
Investigations
on bouncing and attachment of free-rising
air bubbles
on hydrophobic surfaces have been limited to side-view, high-speed
photography of the bubble-plate attachment process. In this work,
an investigation of the dynamics as well as stability of thin liquid
films (TLFs) between free-rising air bubbles and quartz surfaces was
performed using a newly developed multiple-wavelength synchronized
reflection interferometry microscopy (SRIM) technique. The effect
of surface hydrophobicity on both the stability and critical rupture
thickness of TLFs was investigated. Results showed that the TLF ruptured
at a critical rupture thickness of 100–1000 nm or beyond during
bubble’s impact on hydrophobic quartz surfaces. The critical
rupture thicknesses varied depending on the surface hydrophobicity
as well as surface asperity. A higher surface hydrophobicity, in general,
contributed to a higher critical rupture thickness. In addition, the
effect of n-octanol on the stability of the TLFs
was investigated. Results showed that film stability increased with
increasing the concentration of n-octanol, which
was accompanied by a significant decrease in the critical rupture
thickness. The present result illustrates, for the first time, the
dynamics of TLFs on hydrophobic surfaces under a dynamic condition
compared with previous studies under a quasi-equilibrium condition.
The information revealed from the present work has a significant implication
to many industrial applications, including froth flotation and other
biological and semiconductor applications.