Determination of critical micellar aggregation numbers by steady-state fluorescence probe method

Aggregation numbers of micelle (N-m) of SDS and AS were determined by steady-state fluorescence probe method in which pyrene was used as fluorescence probe and benzophenone as quencher. Satisfactory results were obtained as shown in Fig. 1 similar to2 when the solution of surfactant was prepared with a saturated aqueous solution of pyrene and the optimum concentration of benzophenone was selected in 0 similar to1.00 mmol L-1. The experimental results in Fig. 3 similar to5 and Table 4 show that when concentration of surfactant is in 5 similar to9 times of cmc, N-m increases linearly with the increase of concentration and fluctuats slightly with the increment of temperature. It is indicated that N-m is an eigenvalue at c = cmc, which has been defined here from as the critical micellar aggregation number [N-m].[N-m] can be extrapolated from N(m)similar toc(SAA) experimental curves, as shown in Table 3 for SDS 57 (25 degreesC) and 49 (40 degreesC) and for AS 55 (40 degreesC), respectively.