Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: Interfaces
CPP 5.2: Vortrag
Montag, 23. März 2009, 10:45–11:00, ZEU 160
Wetting and surface tension dynamics of aqueous anionic surfactant/cationic polyelectrolyte mixtures — Radomir Slavchov1,2, Borjan Radoev1, Gudrun Petzold2, Burkhard Breitzke3, and •Victoria Dutschk2 — 1Faculty of Chemistry, University of Sofia, Bulgaria — 2Leibniz Institute of Polymer Research — 3Sasol Germany, Marl
Surfactant-polyelectrolyte interactions in aqueous mixtures were studied using dynamic surface tension, polyelectrolyte titration, nephelometric turbidity and dynamic light scattering. A cationic polyelectrolyte (hydroxyethylcellulose, HEC) was used in combination with two anionic surfactants in surfactant classes AS (alkyl or fatty alcohol sulphates) and LES (lauryl ether sulphates) of similar structure but different hydrophibicity.
Systematic studies of the dynamic surface tension and contact angles of aqueous solutions of single components as wells as of their mixtures led to an indirect estimation of the interactions both at the liquid-vapour and solid-liquid (highly hydrophobic) interfaces. Here, differences in the wetting kinetics depend on adsorption mechanisms.
Evidently, hydrophobic surfaces show the same or similar adsorption kinetics at the solid-liquid interface as to be expected in the case of the liquid-vapour interface. Besides, the current state of the air interface (dynamic surface tension) at the instance of the drop-surface contact determines the contact angles on hydrophobic surfaces.