Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates

We study the wetting properties of very small droplets of salty aqueous suspensions of unilamellar liposomes of DMPC (dimyristoylphosphatidylcholine), situated on SiO2–glass surfaces with different levels of hydrophobicity. We evaluated two different measures of hydrophobicity of solid surfaces - re...

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Main Authors: Alexandrova, L., Karakashev, S.I., Grigorov, L., Phan, Chi, Smoukov, S.
Format: Journal Article
Published: Elsevier BV 2015
Online Access:http://hdl.handle.net/20.500.11937/4288
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author Alexandrova, L.
Karakashev, S.I.
Grigorov, L.
Phan, Chi
Smoukov, S.
author_facet Alexandrova, L.
Karakashev, S.I.
Grigorov, L.
Phan, Chi
Smoukov, S.
author_sort Alexandrova, L.
building Curtin Institutional Repository
collection Online Access
description We study the wetting properties of very small droplets of salty aqueous suspensions of unilamellar liposomes of DMPC (dimyristoylphosphatidylcholine), situated on SiO2–glass surfaces with different levels of hydrophobicity. We evaluated two different measures of hydrophobicity of solid surfaces - receding contact angles and the thickness of wetting films trapped between an air bubble and the solid surface at different levels of hydrophobicity. We established a good correlation between methods which differ significantly in measurement difficulty and experimental setup. We also reveal details of the mechanism of wetting of different surfaces by the DMPC liposome suspension. Hydrophilic surfaces with water contact angles in the range of 0° to 35° are readily hydrophobized by the liposomes and only showed corresponding contact angles in the range 27°-43°. For same range of surface hydrophobicities, there was a clear reduction of the thickness of the wetting films between the surface and a bubble, reaching a minimum in the 35°-40° range. At higher levels of hydrophobicity both pure water and the liposome suspension show similar contact angles, and the thickness of wetting films between a bubble and those surfaces increases in parallel. Our analysis showed that the only force able to stabilize the film under these experimental conditions is steric repulsion. The latter suggests that nanobubbles adsorbed on hydrophobic parts of the surface, and coated with a DMPC layer, may be the cause of the 40-70 nm thickness of wetting films we observe.
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spelling curtin-20.500.11937-42882017-09-13T14:47:34Z Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates Alexandrova, L. Karakashev, S.I. Grigorov, L. Phan, Chi Smoukov, S. We study the wetting properties of very small droplets of salty aqueous suspensions of unilamellar liposomes of DMPC (dimyristoylphosphatidylcholine), situated on SiO2–glass surfaces with different levels of hydrophobicity. We evaluated two different measures of hydrophobicity of solid surfaces - receding contact angles and the thickness of wetting films trapped between an air bubble and the solid surface at different levels of hydrophobicity. We established a good correlation between methods which differ significantly in measurement difficulty and experimental setup. We also reveal details of the mechanism of wetting of different surfaces by the DMPC liposome suspension. Hydrophilic surfaces with water contact angles in the range of 0° to 35° are readily hydrophobized by the liposomes and only showed corresponding contact angles in the range 27°-43°. For same range of surface hydrophobicities, there was a clear reduction of the thickness of the wetting films between the surface and a bubble, reaching a minimum in the 35°-40° range. At higher levels of hydrophobicity both pure water and the liposome suspension show similar contact angles, and the thickness of wetting films between a bubble and those surfaces increases in parallel. Our analysis showed that the only force able to stabilize the film under these experimental conditions is steric repulsion. The latter suggests that nanobubbles adsorbed on hydrophobic parts of the surface, and coated with a DMPC layer, may be the cause of the 40-70 nm thickness of wetting films we observe. 2015 Journal Article http://hdl.handle.net/20.500.11937/4288 10.1016/j.cis.2014.08.003 Elsevier BV restricted
spellingShingle Alexandrova, L.
Karakashev, S.I.
Grigorov, L.
Phan, Chi
Smoukov, S.
Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title_full Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title_fullStr Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title_full_unstemmed Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title_short Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2–glass plates
title_sort wetting properties of phospholipid dispersion on tunable hydrophobic sio2–glass plates
url http://hdl.handle.net/20.500.11937/4288