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Influence of dissolved gas on the interaction between hydrophobic surfaces in water

Wennerström, Håkan LU (2003) In The Journal of Physical Chemistry Part B 107(50). p.13772-13773
Abstract
We analyze how the interaction between two hydrophobic surfaces in water depends on the amount of dissolved gas. At equilibrium there is, for a truly hydrophobic surface with contact angle theta > 90degrees, a long range attractive force. The attraction is due to the formation of a gaseous film between the surfaces. For a completely degassed sample the gas consists of water vapor and the range of the force is of order 500 nm at ambient conditions. In the other extreme where the water

s saturated with gas with respect to the atmosphere the range of the equilibrium force is determined by the hydrostatic pressure and it diverges as the distance between the surface setup and the air-water interface goes to zero. It is generally... (More)
We analyze how the interaction between two hydrophobic surfaces in water depends on the amount of dissolved gas. At equilibrium there is, for a truly hydrophobic surface with contact angle theta > 90degrees, a long range attractive force. The attraction is due to the formation of a gaseous film between the surfaces. For a completely degassed sample the gas consists of water vapor and the range of the force is of order 500 nm at ambient conditions. In the other extreme where the water

s saturated with gas with respect to the atmosphere the range of the equilibrium force is determined by the hydrostatic pressure and it diverges as the distance between the surface setup and the air-water interface goes to zero. It is generally considered that the formation of a gaseous film is a kinetically very slow process so that one in practice stays on the metastable liquid branch until an instability appears at short separations. For the particular case of formation and stability of oil in water emulsions in the absence of stabilizer a degassing will affect at least two crucial steps in the process. In the formation of droplets, new interfaces are formed and separated from short distances. The presence of dissolved gas, in both oil and water, facilitates the formation of gas bubbles between the surfaces. Furthermore, the lifetime of gas bubbles adsorbed on the interface is substantially prolonged in the presence of dissolved gas and they can act as nucleation centers for the formation of a gaseous le

s between two oil droplets at re-encounters. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
107
issue
50
pages
13772 - 13773
publisher
The American Chemical Society
external identifiers
  • wos:000187279200006
  • scopus:0347568220
ISSN
1520-5207
DOI
10.1021/jp030927w
language
English
LU publication?
yes
id
791c61af-506f-44b8-9c41-3a11c8c60bf9 (old id 122258)
date added to LUP
2007-07-12 14:04:21
date last changed
2018-05-29 10:17:51
@article{791c61af-506f-44b8-9c41-3a11c8c60bf9,
  abstract     = {We analyze how the interaction between two hydrophobic surfaces in water depends on the amount of dissolved gas. At equilibrium there is, for a truly hydrophobic surface with contact angle theta &gt; 90degrees, a long range attractive force. The attraction is due to the formation of a gaseous film between the surfaces. For a completely degassed sample the gas consists of water vapor and the range of the force is of order 500 nm at ambient conditions. In the other extreme where the water <br/><br>
s saturated with gas with respect to the atmosphere the range of the equilibrium force is determined by the hydrostatic pressure and it diverges as the distance between the surface setup and the air-water interface goes to zero. It is generally considered that the formation of a gaseous film is a kinetically very slow process so that one in practice stays on the metastable liquid branch until an instability appears at short separations. For the particular case of formation and stability of oil in water emulsions in the absence of stabilizer a degassing will affect at least two crucial steps in the process. In the formation of droplets, new interfaces are formed and separated from short distances. The presence of dissolved gas, in both oil and water, facilitates the formation of gas bubbles between the surfaces. Furthermore, the lifetime of gas bubbles adsorbed on the interface is substantially prolonged in the presence of dissolved gas and they can act as nucleation centers for the formation of a gaseous le<br/><br>
s between two oil droplets at re-encounters.},
  author       = {Wennerström, Håkan},
  issn         = {1520-5207},
  language     = {eng},
  number       = {50},
  pages        = {13772--13773},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Influence of dissolved gas on the interaction between hydrophobic surfaces in water},
  url          = {http://dx.doi.org/10.1021/jp030927w},
  volume       = {107},
  year         = {2003},
}