Eur. Phys. J. E 6, 315-323 (2001)
Adsorption from pure and mixed vapours of n-hexane and n-perfluorohexane
M.M. Kohonen and H.K. ChristensonDepartment of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra A.C.T. 0200, Australia mika.kohonen@physik.uni-ulm.de
(Received 30 July 2001)
Abstract
We have used a modified surface force apparatus (SFA) to
study adsorption onto mica surfaces from near-saturated vapours of
n-hexane and n-perfluorohexane, and mixtures thereof. For
relative vapour pressures in the range 0.9-0.998 the films
adsorbed from vapours of the pure liquids range in thickness from
1 to 4 nm, in crude agreement with the predictions of
non-retarded van der Waals-Lifshitz theory. The observed
deviations from theory show a qualitative difference between the
two liquids, which may reflect differences in the significance of
structural contributions to the disjoining pressure. Under the same
experimental conditions, adsorption from vapours of (one-phase)
liquid mixtures gives rise to films which are significantly
thicker, over a broad range of intermediate compositions, than
those adsorbed from the pure vapours, with a broad maximum in
thickness observed near the critical composition of the bulk
liquid mixture.
68.08.Bc - Wetting.
68.15.+e - Liquid thin films.
64.75.+g - Solubility, segregation, and mixing; phase separation.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
