title: Influence of nanobubbles on the adsorption of nanoparticles.
abstract: A quartz crystal microbalance was used to study the influence of nanobubbles on the adsorption of polystyrene nanoparticles onto surfaces coated with gold, or coated with dodecanethiol or mercaptoundecanoic acid self-assembled monolayers (SAMs). Adsorption of the nanoparticles onto the surface causes the resonant frequency of the quartz crystal to decrease. We found that particles were adsorbed onto the gold-coated quartz crystal in air-rich water, but not in degassed water. This finding supports the long-standing hypothesis that nanobubbles play a key role in the long-range attractive force between hydrophobic surfaces in aqueous solutions. When the experiments were conducted using quartz crystals coated with a hydrophobic dodecanethiol SAM, the nanoparticles were adsorbed onto the surface even in degassed water due to the short-range hydrophobic interactions between the nanoparticles and the dodecanethiol molecules. In contrast, the nanoparticles were adsorbed to a lesser degree onto the hydrophilic mercaptoundecanoic acid-coated crystals due to electrostatic repulsive forces.
authors.affiliation: Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Korea.
authors.forename: Hyejung
authors.initials: H
authors.lastname: Seo
authors.forename: Myungsun
authors.initials: M
authors.lastname: Yoo
authors.forename: Sangmin
authors.initials: S
authors.lastname: Jeon