Issue 13, 2022

Unraveling the effects of gas species and surface wettability on the morphology of interfacial nanobubbles

Abstract

The morphology of interfacial nanobubbles (INBs) is a crucial but controversial topic in nanobubble research. We carried out atomistic molecular dynamics (MD) simulations to comprehensively study the morphology of INBs controlled by several determinant factors, including gas species, surface wettability, and bubble size. The simulations show that H2, O2 and N2 can all form stable INBs, with the contact angles (CAs, on the liquid side) following the order CA(H2) < CA(N2) < CA(O2), while CO2 prefers to form a gas film (pancake) structure on the substrate. The CA of INBs demonstrates a linear relation with the strength of interfacial interaction; however, a limited bubble CA of ∼25° is found on superhydrophilic surfaces. The high gas density and high internal pressure of the INBs are further confirmed, accompanied by strong interfacial gas enrichment (IGE) behavior. The morphology study of differently sized INBs shows that the internal density of the gas is drastically decreased with the bubble size at the initial stage of bubble nucleation, while the CA remains almost constant. Based on the simulation results, a modified Young's equation is presented for describing the extraordinary morphology of INBs.

Graphical abstract: Unraveling the effects of gas species and surface wettability on the morphology of interfacial nanobubbles

Supplementary files

Article information

Article type
Paper
Submitted
04 Jan 2022
Accepted
24 May 2022
First published
24 May 2022
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2022,4, 2893-2901

Unraveling the effects of gas species and surface wettability on the morphology of interfacial nanobubbles

K. Hu, L. Luo, X. Sun and H. Li, Nanoscale Adv., 2022, 4, 2893 DOI: 10.1039/D2NA00009A

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