Determination of Micellar Aggregation Numbers of Gemini Surfactant in Aqueous Solution by Steady-State Fluorescence Quenching Method

Abstract

A new kind of Gemini surfactant synthesized from the intermediate 1-bromo-2-(2-bromoethoxy) ethane and dodecyl dimethyl amine by using isopropanol as solvent. The critical micellar concentration (CMC) value of Gemini 12-Y-12 determined by Steady-state fluorescence quenching (SSFQ) method is basically in agreement with the value by surface tension method. The micellar aggregation numbers (N_agg) of this surfantant are essentially constant when the concentrations of the quencher were selected in 2.0 × 10^-4-5.0 × 10^-4 mol L^-1. The N_agg of the Gemini surfactant increases linearly with the increase of surfactant concentration in the range of 4-9 times of critical micellar concentration and critical micellar aggregation numbers obtained by extrapolation method is 13.2.