The interplay among gas, liquid and solid interactions determines the stability of surface nanobubbles. Issue 44 (10th November 2020)

• Record Type: Journal Article
• Authors: Tortora, Marco; Meloni, Simone; Tan, Beng Hau; Giacomello, Alberto; Ohl, Claus-Dieter; Casciola, Carlo Massimo
• Is Part Of: Nanoscale. Volume 12:Issue 44(2020)
• Page Start: 22698
• Page End: 22709
• Publication Date: 2020-11-10
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr05859a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We develop a comprehensive theory explaining the stability, instability and other properties of surface nanobubbles under all known experimental conditions. Abstract : Surface nanobubbles are gaseous domains found at immersed substrates, whose remarkable persistence is still not fully understood. Recently, it has been observed that the formation of nanobubbles is often associated with a local high gas oversaturation at the liquid–solid interface. Tan, An and Ohl have postulated the existence of an effective potential attracting the dissolved gas to the substrate and producing a local oversaturation within 1 nm from it that can stabilize nanobubbles by preventing outgassing in the region where gas flow would be maximum. It is this effective solid–gas potential – which is not the intrinsic, mechanical interaction between solid and gas atoms – its dependence on chemical and physical characteristics of the substrate, gas and liquid, that controls the stability and the other characteristics of surface nanobubbles. Here, we perform free energy atomistic calculations to determine, for the first time, the effective solid–gas interaction that allows us to identify the molecular origin of the stability and other properties of surface nanobubbles. By combining the Tan–An–Ohl model and the present results, we provide a comprehensive theoretical framework allowing, among others, the interpretation of recent unexplained experimental results, such as the stability of surface nanobubbles in degassed liquids, the very high gas concentration in the liquid surrounding nanobubbles, and nanobubble instability in organic solvents with high gas solubility.