SELF-ORGANIZATION OF POLY(ALLYLAMINE)S CONTAINING HYDROPHOBIC GROUPS AND ITS EFFECT ON THE INTERACTION WITH SMALL MOLECULES .1. STATIC FLUOROMETRY

Amphiphilic cationic polyelectrolytes, poly(allylamine)s (PAA), with long alkyl groups or a benzyl group show high surface activity in aqueous solutions. Viscosity measurements indicated that the polymers were in a compact conformation. The present work examines the interaction of the amphiphilic polymers with various fluorescent probes and compares the behavior of the fluorescent-labeled polymers. Dodecylated PAA with a degree of substitution (DS) of more than 0.12 and benzylated PAA (DS > 0.5) were found to form a hydrophobic domain similar to a micelle formed by the usual surfactants. It is suggested that at pH 9 the former has a compact core in the interior of the domain and that the latter is sterically capable of accepting probe molecules. The hydrophobic domain is less polar and more dense than the surfactant micelle. The longer the alkyl groups in PAA and the higher the DS, the lower the polarity of the domain is and the higher the inclusion of the substrate is. At pH 9, the inclusion of small molecules by the domain is mainly due to hydrophobic interactions; electrostatic interactions play a minor role. On the other hand, it is suggested that in a neutral aqueous solution conformational change of the polymer exerts an influence on the inclusion and electrostatic interation makes a contribution.