Bubble characterizations on hydrophobic surface using lattice Boltzmann simulation with large density ratios

Purpose The maintenance of the air–water interface is crucial for the drag reduction on hydrophobic surfaces. But the air bubbles become unstable and even washed away under high speed flow, causing the failure of surface hydrophobicity. Thereby, this paper aims to understand the relations between bubble behaviors and surface properties, flow conditions and to discover new methods to maintain the air–water interface. Design/methodology/approach Bubble properties on hydrophobic surfaces were characterized using single-component multiphase lattice Boltzmann simulation. Three equations of state (EOSs), including the Peng–Robinson, Carnahan–Starling and modified Kaplun–Meshalkin EOSs, were incorporated to achieve high density ratios. Findings Both the static and dynamic properties of bubbles on hydrophobic surfaces were investigated and analyzed under different flow conditions, solid–liquid interactions and surface topology. Originality/value By revealing the properties of bubbles on hydrophobic surfaces, the effects of flow conditions and surface properties were characterized. The maintenance method of air–water interface can be proposed according to the bubble properties in the study.

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Diffusion characteristics of air pockets on hydrophobic surfaces in channel flow: Three-dimensional measurement of air-water interface

Physical Review Fluids ◽

10.1103/physrevfluids.4.074001 ◽

2019 ◽

Vol 4 (7) ◽

Cited By ~ 1

Author(s):

Hyunseok Kim ◽

Hyungmin Park

Keyword(s):

Channel Flow ◽

Three Dimensional ◽

Water Interface ◽

Hydrophobic Surfaces ◽

Dimensional Measurement ◽

Diffusion Characteristics ◽

Air Water Interface ◽

Three Dimensional Measurement ◽

Air Pockets

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Nanoparticle interaction with model lung surfactant monolayers

Journal of The Royal Society Interface ◽

10.1098/rsif.2009.0329.focus ◽

2009 ◽

Vol 7 (suppl_1) ◽

Cited By ~ 83

Author(s):

Rakesh Kumar Harishchandra ◽

Mohammed Saleem ◽

Hans-Joachim Galla

Keyword(s):

Surface Properties ◽

Self Assembly ◽

Current Knowledge ◽

Surface Film ◽

Lung Surfactant ◽

Hydrophobic Surface ◽

Surface Pattern ◽

Lipid Monolayers ◽

Water Interface ◽

Air Water Interface

One of the most important functions of the lung surfactant monolayer is to form the first line of defence against inhaled aerosols such as nanoparticles (NPs), which remains largely unexplored. We report here, for the first time, the interaction of polyorganosiloxane NPs (AmorSil20: 22 nm in diameter) with lipid monolayers characteristic of alveolar surfactant. To enable a better understanding, the current knowledge about an established model surface film that mimics the surface properties of the lung is reviewed and major results originating from our group are summarized. The pure lipid components dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol have been used to study the biophysical behaviour of their monolayer films spread at the air–water interface in the presence of NPs. Film balance measurements combined with video-enhanced fluorescence microscopy have been used to investigate the formation of domain structures and the changes in the surface pattern induced by NPs. We are able to show that NPs are incorporated into lipid monolayers with a clear preference for defect structures at the fluid–crystalline interface leading to a considerable monolayer expansion and fluidization. NPs remain at the air–water interface probably by coating themselves with lipids in a self-assembly process, thereby exhibiting hydrophobic surface properties. We also show that the domain structure in lipid layers containing surfactant protein C, which is potentially responsible for the proper functioning of surfactant material, is considerably affected by NPs.

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Effect of Chain Microstructure and Subphase pH on the Surface Properties and Aggregation Behavior of Amphiphilic Copolymers Based on Fluoroacrylates

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.816.312 ◽

2019 ◽

Vol 816 ◽

pp. 312-317

Author(s):

Alexandra O. Grigoreva ◽

E.Y. Polozov ◽

S.D. Zaitsev

Keyword(s):

Acrylic Acid ◽

Surface Properties ◽

Butyl Acrylate ◽

Langmuir Monolayer ◽

Aggregation Behavior ◽

Reactivity Ratios ◽

Water Interface ◽

Amphiphilic Copolymers ◽

Air Water Interface ◽

Raft Agent

Copolymerization of 2,2,3,3,4,4,5,5-octafluoropentyl acrylate (OFPA) and acrylic acid (AA), OFPA and tert-butyl acrylate (t-BA) in presence ofdibenzylcarbonotrithioate (BTC) and polymeric RAFT-agents was studied, reactivity ratios were calculated. It was shown that type of RAFT-agent can influence on chain microstructure of obtained polymers. Aggregation behavior of obtained amphiphilic copolymers with different microstructures at the air/water interface was characterized by the Langmuir monolayer technique. The effect of the microstructureand subphase pH on the isotherm curves were shown.

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