The Relationship Between Nanobubbles and the Hydrophobic Force

Palmer, Lauren A.; Cookson, David J.; Lamb, Robert N.

doi:10.1021/la1029678

Cited by 17 publications

(12 citation statements)

References 17 publications

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“…Finally, Small-Angle X-ray Scattering (SAXS) experiments have investigated the formation of NBs on hydrophobic SAMs surface in a binary ethanol/water titration [113]. SAXS revealed an electron density depletion layer at the hydrophobic interface with changing air solubility in the immersing liquid due to the NB formation [113]. Hence, NB formation was responsible for the so-called long-range hydrophobic force [113].…”

Section: Methodsmentioning

confidence: 99%

“…SAXS revealed an electron density depletion layer at the hydrophobic interface with changing air solubility in the immersing liquid due to the NB formation [113]. Hence, NB formation was responsible for the so-called long-range hydrophobic force [113]. Other methods to study NBs include the Fluorescence Lifetime Imaging Microscopy (FLIM, see Fig.…”

Section: Methodsmentioning

confidence: 99%

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Surface nanobubbles: Theory, simulation, and experiment. A review

Theodorakis

Che

2019

Advances in Colloid and Interface Science

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Surface nanobubbles (NBs) are stable gaseous phases in liquids that form at the interface with solid substrates. They have been particularly intriguing for their high stability that contradicts theoretical expectations and their potential relevance for many technological applications. Here, we present the current state of the art in this research area by discussing and contrasting main results obtained from theory, simulation and experiment, and presenting their limitations.We also provide future perspectives anticipating that this review will stimulate further studies in the research area of surface NBs.The subsequent sections of this review article are organised as follows: In Sec. 2, we present a range of different theoretical, simulation and experimental methodologies, which are used to study surface NBs discussing their limitations and contrasting main results. In Sec. 3, we discuss the main morphological and mechanical characteristics of surface NBs. In Sec. 4, we provide a review of the main experimental methods to generate surface NBs. In Sec. 5, we discuss the main hypothesis that supports the intriguing high NBs' stability, i.e. contactline pinning. Finally, we present our perspectives in the research area of surface NBs in Sec. 6.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Surface nanobubbles: Theory, simulation, and experiment. A review

Theodorakis

Che

2019

Advances in Colloid and Interface Science

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“…The solvent exchange process has meanwhile successfully been applied in many research groups to produce surface nanobubbles; see, e.g., Martinez and Stroeve (2007), S. Yang et al ( , 2008, Hampton, Donose, and Nguyen (2008), Palmer, Cookson, and Lamb (2011), Chan and Ohl (2012), Ishida, Kusaka, and Ushijima (2012), Karpitschka et al (2012), and Belova et al (2013). We discuss many of these papers later in this section and in Sec.…”

Section: Solution Bmentioning

confidence: 99%

“…Apart from the techniques discussed previously, several other techniques have also been used to examine the surface nanobubbles, namely, neutron reflectivity measurements (Schwendel et al, 2003;Steitz et al, 2003) and small angle x-ray scattering (Palmer, Cookson, and Lamb, 2011).…”

Section: E Further Techniques For the Study Of Surface Nanobubblesmentioning

confidence: 99%

Surface nanobubbles and nanodroplets

2015

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Surface nanobubbles are nanoscopic gaseous domains on immersed substrates which can survive for days. They were first speculated to exist about 20 years ago, based on stepwise features in force curves between two hydrophobic surfaces, eventually leading to the first atomic force microscopy (AFM) image in 2000. While in the early years it was suspected that they may be an artifact caused by AFM, meanwhile their existence has been confirmed with various other methods, including through direct optical observation. Their existence seems to be paradoxical, as a simple classical estimate suggests that they should dissolve in microseconds, due to the large Laplace pressure inside these nanoscopic spherical-capshaped objects. Moreover, their contact angle (on the gas side) is much smaller than one would expect from macroscopic counterparts. This review will not only give an overview on surface nanobubbles, but also on surface nanodroplets, which are nanoscopic droplets (e.g., of oil) on (hydrophobic) substrates immersed in water, as they show similar properties and can easily be confused with surface nanobubbles and as they are produced in a similar way, namely, by a solvent exchange process, leading to local oversaturation of the water with gas or oil, respectively, and thus to nucleation. The review starts with how surface nanobubbles and nanodroplets can be made, how they can be observed (both individually and collectively), and what their properties are. Molecular dynamic simulations and theories to account for the long lifetime of the surface nanobubbles are then reported on. The crucial element contributing to the long lifetime of surface nanobubbles and nanodroplets is pinning of the three-phase contact line at chemical or geometric surface heterogeneities. The dynamical evolution of the surface nanobubbles then follows from the diffusion equation, Laplace's equation, and Henry's law. In particular, one obtains stable surface nanobubbles when the gas influx from the gas-oversaturated water and the outflux due to Laplace pressure balance. This is only possible for small enough surface bubbles. It is therefore the gas or oil oversaturation ζ that determines the contact angle of the surface nanobubble or nanodroplet and not the Young equation. The review also covers the potential technological relevance of surface nanobubbles and nanodroplets, namely, in flotation, in (photo)catalysis and electrolysis, in nanomaterial engineering, for transport in and out of nanofluidic devices, and for plasmonic bubbles, vapor nanobubbles, and energy conversion. Also given is a discussion on surface nanobubbles and nanodroplets in a nutshell, including theoretical predictions resulting from it and future directions. Studying the nucleation, growth, and dissolution dynamics of surface nanobubbles and nanodroplets will shed new light on the problems of contact line pinning and contact angle hysteresis on the submicron scale.

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“…Studies show that NBs can promote physiological activity of living organisms and increase cell productivity [ 18 ]. They are responsible for long-range attractive hydrophobic forces [ 19 – 20 ]. The coalescence of NBs on hydrophobic surfaces is believed to form a gas bridge and leads to long-range attractive forces [ 19 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Automatic morphological characterization of nanobubbles with a novel image segmentation method and its application in the study of nanobubble coalescence

Wang

et al. 2015

Beilstein J. Nanotechnol.

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SummaryNanobubbles (NBs) on hydrophobic surfaces in aqueous solvents have shown great potential in numerous applications. In this study, the morphological characterization of NBs in AFM images was carried out with the assistance of a novel image segmentation method. The method combines the classical threshold method and a modified, active contour method to achieve optimized image segmentation. The image segmentation results obtained with the classical threshold method and the proposed, modified method were compared. With the modified method, the diameter, contact angle, and radius of curvature were automatically measured for all NBs in AFM images. The influence of the selection of the threshold value on the segmentation result was discussed. Moreover, the morphological change in the NBs was studied in terms of density, covered area, and volume occurring during coalescence under external disturbance.

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The Relationship Between Nanobubbles and the Hydrophobic Force

Cited by 17 publications

References 17 publications

Surface nanobubbles: Theory, simulation, and experiment. A review

Surface nanobubbles: Theory, simulation, and experiment. A review

Surface nanobubbles and nanodroplets

Automatic morphological characterization of nanobubbles with a novel image segmentation method and its application in the study of nanobubble coalescence

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