Aggregation of Sodium 2,4,5-(tri-n-Alkyl)-benzene Sulfonates in Aqueous Solution: Micellization and Microenvironment Characteristics Studied by Electron Paramagnetic Resonance and Steady-State Fluorescence Quenching

Abstract

The aggregation behaviors and microenvironmental characteristics of five sodium tri-n-alkylbenzene sulfonates (STABS) micelles have been investigated by electron paramagnetic resonance (EPR) and steady-state fluorescence quenching (SSFQ) techniques. The results indicated that the micropolarity of STABS micelles was less sensitive to the increase of the alkyl chain length, and showed slight decrease with the increasing solution concentration. The microviscosity of STABS micelles increased with the increase of the long alkyl chain length, decreased with the increase of the short alkyl chain length, and exhibited little increase when increase the solution concentration. The salinity of added inorganic salt exhibited obvious effect on the decrease of micropolarity and increase of microviscosity of STABS. These results suggested that these different alkyl chains showed different effects on the micellization of STABS and the salinity's effect was even bigger.

Keywords:

• Electron paramagnetic resonance
• micellization
• microenvironment
• sodium tri-n-Alkyl-benzene sulfonates
• steady-state fluorescence quenching

Acknowledgements

This work was financially supported by the National Science & Technology Major Project (2008ZX05011) of China.