Micellar Systems as Devices for Enhancing the Lifetimes and Concentrations of Free Radicals


Optical modulation spectroscopy was used to monitor the second-order decay kinetics of phenylthiyl (I) and mesitythiyl radicals (II) in both heptane and sodium dodecyl sulfate (SDS) solutions. The self-reactions of the thiyl radicals were found to be diffusion controlled in the hydrocarbon solvent. Little change was observed in the decay kinetics of I when the solvent was aqueous SDS (0.2 M), suggesting that the radical was not strongly partitioned into the micelles. However, enhancements of a factor of ca. 50 in both the lifetime and concentration of II were observed in 0.05 M SDS, implying that the larger radical was effectively caged within the micelles. Kinetic analysis led to a value of 2 X 103s-1 for the exit rate constant of II from SDS micelles. © 1985, American Chemical Society. All rights reserved.

Publication Title

Journal of the American Chemical Society