Thermodynamics of superspreading
A. Kabalnov
Hewlett Packard Company, 1000 NE Circle Blvd.,
Corvallis OR 97330, USA
alexey_kabalnov@ex.cv.hp.com
Received 19 May 1999 and Received in final form 29 October 1999
Abstract
A simple model for calculation of the spreading
coefficient of an aqueous surfactant solution on an apolar solid
is proposed. The spreading coefficient is predicted to have two
components: i) the van der Waals component, which is similar to
the spreading coefficient of the alkane, making up the surfactant
tail; and ii) the monolayer frustration component, dependent on
the bending moduli and the spontaneous curvature of the
surfactant. The frustration term is minimized at a negative
spontaneous curvature. In order for a solution to spread, the van
der Waals component of the spreading coefficient must be positive
and larger than the monolayer frustration term. The spreading is
facilitated by surfactants having very short and branched alkyl
tails.
PACS
68.45.Gd Wetting - 68.10.Gw Interface
activity, spreading - 68.10.-m Fluid surfaces and fluid-fluid
interfaces
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
