Summary: On bridging bubbles between hydrophobic surfaces
Phil Attard
Department of Physics, Faculty of Science,
Australian National University, Canberra, ACT, 0200, Australia.
(Langmuir 12, 1693­1695 (1996))
The thermodynamic stability of bubbles and
bridging vapor cavities is re­analyzed. It is shown
that bubbles are stable in the isobaric ensemble, and
that a bubble stuck to a surface, particularly a hy­
drophobic surface, has a lower Gibbs free energy than
when in bulk water. It is also pointed out that va­
por cavities bridging between two hydrophobic sur­
faces have a local grand potential minimum at sub­
microscopic radii, and are therefore mechanically sta­
ble even though the contact angle is greater than the
bulk one. It is concluded that bubbles or cavities
bridging between two hydrophobic surfaces are a vi­
able possibility for the long range attractions that
have been measured.
The intimate connection between bubbles and

Source: Attard, Phil - School of Chemistry, University of Sydney

Collections: Chemistry