Eur. Phys. J. E 5, 51-58
Adsorption of hydrophobic polyelectrolytes at the air/water interface: Conformational effect and history dependenceO. Théodoly, R. Ober and C.E. Williams
Laboratoire des Fluides Organisés (URA 792 du CNRS) , Physique de la Matière Condensée, Collège de France, 11 place M. Berthelot, 75005 Paris, France email@example.com or firstname.lastname@example.org
(Received 16 June 2000 )
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