MICELLIZATION OF [1-(ETHOXYCARBONYL)PENTADECYL]TRIMETHYL-AMMONIUM BROMIDE STUDIED BY CONDUCTOMETRY AND POTENTIOMETRY

Micellization of the title compound, an antimicrobially active surfact ant (Septonex), was studied in aqueous solution by conductometry and p otentiometry with ion-selective electrodes. The effect of temperature and concentration of bromide anions (addition of KBr) upon critical mi celle concentration (CMC) of the surfactant was determined, together w ith the degree of association of the formed cationic micelles with bro mide counterions. The concentrations of the free quaternary ammonium c ations and free bromide anions were determined in the micellar solutio n of the surfactant in the range from CMC (0.0008 mol dm-3) to 0.1 mol dm-3 . The results corroborate the formation of relatively small mice lles at CMC, which grow continually with the increasing concentration of the surfactant, while the concentration of its free quaternary cati ons de creases.