Eur. Phys. J. E 5, 87-96
Adsorption of anionic polyelectrolytes to dioctadecyldimethylammonium bromide monolayers
J. Engelking and H. MenzelInstitut für Makromolekulare Chemie der Universität Hannover, Am Kleinen Felde 30, 30167 Hannover, Germany Menzel@mbox.imc.uni-hannover.de
(Received 1st July 2000 and Received in final form 7 December 2000 )
Abstract
Monolayers of dioctadecyldimethylammonium bromide (DODA) at the air/water interface
were used as model for charged surfaces to study the adsorption of anionic polyelectrolytes.
After spreading on a pure water surface the monolayers were compressed and subsequently
transferred onto a polyelectrolyte solution employing the Fromherz technique. The
polyelectrolyte adsorption was monitored by recording the changes in surface pressure at
constant area. For poly(styrene sulfonate) and carboxymethylcellulose the plot of the surface
pressure as function of time gave curves which indicate a direct correlation between the
adsorbed amount and surface pressure as well as a solely diffusion controlled process. In the
case of rigid rod-like poly(p-phenylene sulfonate)s the situation is more complicated. Plotting
the surface pressure as function of time results in a curve with sigmoidal shape, characterized
by an induction period. The induction period can be explained by a domain formation, which
can be treated like a crystallization process. Employing the Avrami expression developed for
polymer crystallization, the change in the surface pressure upon adsorption of rigid rod-like
poly(p-phenylene sulfonate)s can be described.
68.18.-g - Langmuir-Blodgett films on liquids.
68.43.Mn - Adsorption/desorption kinetics.
61.41.+e - Polymers, elastomers, and plastics.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
