稳态荧光探针法测定临界胶束聚集数

以芘为荧光探针、二苯甲酮为猝灭剂，用稳态荧光探针法测定了SDS和AS的胶束聚集数(Nm).以芘的饱和水溶液为溶剂配制表面活性剂溶液，二苯甲酮的适宜浓度取小于1.00 mmol?L－1时，可以获得满意的实验结果.当表面活性剂溶液浓度为5～9倍cmc时，Nm随表面活性剂浓度增大而线性增大，而随温度的变化略有波动.cSAA=cmc时，Nm值为一本征值，定义为临界胶束聚集数Nm].Nm]值可从Nm－cSAA实验曲线外延得到.25℃时SDS的临界胶束聚集数Nm]为57；40℃时SDS的Nm]为49，AS的Nm]为55.

Determination of Critical Micellar Aggregation Numbers by Steady-state Fluorescence Probe Method

Aggregation numbers of micelle (Nm) 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.1～2 when the solution of surfactant was prepared with a saturated aqueous solution of pyrene and the optimum concentration of benzophenone was selected in 0～1.00 mmol L－1.The experimental results in Fig.3～5 and Table 4 show that when concentration of surfactant is in 5～9 times of cmc,Nm increases linearly with the increase of concentration and fluctuats slightly with the increment of temperature.It is indicated that Nm is an eigenvalue at c=cmc,which has been defined herefrom as the critical micellar aggregation number Nm].Nm] can be extrapolated from Nm～cSAA experimental curves,as shown in Table 3 for SDS 57 (25℃) and 49 (40℃) and for AS 55 (40℃) ,respectively.