Study on Micelle Formation of Three Homologous Surfactants in Aqueous Solution by Surface Tension, Conductivity, and Fluorescence Measurements

Abstract

The detailed micellization behaviors of three homologous Gemini surfactants, 2-hydroxypropyl-1,3-bis (alkyldimethylammonium chloride) designated as C n -3(OH)-C n (n = 12, 14, 16), were studied by surface tension, conductivity and steady-state fluorescence measurements in the temperature range of 15.0°C to 35.0°C. The critical micelle concentration (cmc), thermodynamic parameters of micellization (, , and ), degree of counterion dissociation (α 0 ) at the cmc, and aggregation number (N agg ) were determined. The results showed that cmc of each surfactant had a minmum value as temperature changed. Value of α 0 increased while that of N agg decreased with the increment of the temperature. At a certain temperature, cmc and α 0 decrease while N agg increases with elongation of the alkyl chain in the surfactant molecule.