THE STUDY OF AGGREGATION PROPERTIES OF SODIUM ALKYLBENZENESULFONATE BY STEADY-STATE FLUORESCENCE

Critical micelle concentration (CMC) and aggregation number of micelle (N) of four sodium branched alkyl benzene sulfonates were determined by steady-state fluorescence probe method in which pyrene was used as fluorescence probe and benzophenone as quencher.Increasing the hydrocarbon chain lenght of sodium branched alkyl benzene sulfonate,CMC values were decreased.The experimental results showed that the optimum concentration of benzophenone was different to different sodium branched alkyl benzene sulfonates and the N increased with increasing the carbon number of the short alkyl chain while the N decreased with increasing the carbon number of the long alkyl chain.It was also found that the N increased with the increasing of the concentration of NaCl while the surround polarity of pyrene probe decreased.