2012 Impact factor 1.824
EPJ E - Soft Matter and Biological Physics
Soft Matter and Biological Physics


Eur. Phys. J. E 5, 87-96

Adsorption of anionic polyelectrolytes to dioctadecyldimethylammonium bromide monolayers

J. Engelking and H. Menzel

Institut 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.

PACS
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