Micellization of Alkyl Trimethyl Ammonium Bromides in Aqueous Solutions–Part 1: Critical Micelle Concentration (CMC) and Ionization Degree

Abstract Conductivities of alkyl trimethyl ammonium bromides (alkyl = hexyl-, octyl-, decyl-, dodecyl-, tetradecyl-, hexadecyl-, and octadecyl-) in aqueous solutions were measured as afunction of molarity of surfactants, length of chain and temperature. Critical micelle concentrations (CMC) were estimated from the dependence of the specific conductivity on molarity of the surfactants. It was determined that the temperature dependence of CMC is U-shaped with aminimum shifting toward higher temperatures with decreasing chain length of the alkyl group. Quantities characterizing behaviors of surfactants below and above CMC were calculated and compared from conductivity measurements. Measured and calculated values of studied compounds were also compared with results of many other authors. The paper has the form of a minireview. It is a comparison of the presented experimental data of alkyltrimethylammonium bromides (C6–C18) with earlier works reported.