Premium
Probing the Effect of Salinity and pH on Surface Interactions between Air Bubbles and Hydrophobic Solids: Implications for Colloidal Assembly at Air/Water Interfaces
Author(s) -
Cui Xin,
Shi Chen,
Zhang Shuo,
Xie Lei,
Liu Jing,
Jiang Dazhi,
Zeng Hongbo
Publication year - 2017
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201700388
Subject(s) - disjoining pressure , laplace pressure , chemical physics , colloid , bubble , chemical engineering , particle (ecology) , aqueous solution , mica , chemistry , surface charge , materials science , nanotechnology , mechanics , thermodynamics , surface tension , composite material , oceanography , engineering , geology , thin film , physics
In this work, a bubble probe atomic force microscope (AFM) was employed to quantify the interactions between two air bubbles and between an air bubble and an octadecyltrichlorosilane (OTS)‐hydrophobized mica under various aqueous conditions. The key parameters (e.g., surface potentials, decay length of hydrophobic attraction) were obtained by analyzing the measured forces through a theoretical model based on Reynolds lubrication theory and an augmented Young–Laplace equation by including effect of disjoining pressure. The bubble‐OTS hydrophobic attraction with a decay length of 1.0 nm was found to be independent of solution pH and salinity. These parameters were further used to predict the attachment of OTS‐hydrophobized particles onto the air/water interface, demonstrating that particle attachment driven by hydrophobic attraction could be facilitated by suppressing electrical double‐layer repulsion at low pH or high salinity condition. This facile methodology can be readily extended to quantify interactions of many other colloidal particles with gas/water and oil/water interfaces, with implications for colloidal assembly at different interfaces in many engineering applications.