Eur. Phys. J. E 5, 51-58
Adsorption of hydrophobic polyelectrolytes at the air/water interface: Conformational effect and history dependence
O. Théodoly, R. Ober and C.E. WilliamsLaboratoire des Fluides Organisés (URA 792 du CNRS) , Physique de la Matière Condensée, Collège de France, 11 place M. Berthelot, 75005 Paris, France claudine.williams@college-de-france.fr or williams@ext.jussieu.fr
(Received 16 June 2000 )
Abstract
We present an experimental study of the adsorption of hydrophobic highly charged
polyelectrolytes on a neutral and hydrophobic surface, the air/water interface. The
polymer was a randomly sulphonated polystyrene with charge fractions between 0.3
and 0.9 and the adsorbed layers were characterised by Langmuir through
measurements, ellipsometry and X-ray reflectivity. The adsorption rate is always very
slow and the resulting layers are very thin (< 3 nm). A maximum of adsorption with
the charge fraction is observed which we relate to the conformation of the chains in
solution. We show that adsorption is partially irreversible, strongly hysteretic and that
the state of an adsorbed layer depends on its history.
61.25.Hq - Macromolecular and polymer solutions; polymer melts; swelling.
68.10.-m - Fluid surfaces and fluid-fluid interfaces.
82.65.Dp - Thermodynamics of surfaces and interfaces.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
