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ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Published monthly
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Micellization of dimethylbenzyldodecylammonium bromide and the micelle association with bromide counterions studied by potentiometry and cryoscopy
F. Kopecký, M. Vojteková, P. Stopjaková, and J. Oremusová
Department of Physical Chemistry, Faculty of Pharmacy,
Comenius University, CS-83232 Bratislava
Abstract: Activities of both cations and anions of the antimicrobial surfactant dimethylbenzyldodecylammonium (benzododecinium) bromide were measured in aqueous solutions above critical micelle concentration (CMC) up to 0.1 mol dm-3 potentiometrically with ion-selective electrodes at 25°C. The concentrations of the free ions in the micellar region and the degree of association of the micelles of benzododecinium cations with bromide counterions were calculated from the activities. CMC 0.0024 mol dm-3 was found and it decreased upon the addition of KBr, approximately after Shinoda equation. Cryoscopically measured osmotic coefficients β of the benzododecinium bromide solutions combined with potentiometric results suggested continuously increasing size of the relatively small micelles above CMC, while the concentrations of the free benzododecinium cations decreased.
Full paper in Portable Document Format: 454a463.pdf
Chemical Papers 45 (4) 463–472 (1991)
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