Absorption and emission studies of solubilization in micelles. Part 4.—Studies on cationic micelles with added electrolyte and on lecithin vesicles: excimer formation and the Ham effect

Abstract

The diffusion of pyrene, and thus other large planar aromatic molecules, is shown to take place in a shell close to the double-layer of cationic micelles. Perturbation of the pyrene π-electrons is demonstrated by vibronic band intensity comparisons, i.e. the Ham effect, and used to discuss dielectric leakage into the hydrophobic part of the micelle. Aggregation numbers and pyrene diffusional characteristics are described for lecithin vesicles. The effect of added electrolyte (NaBr) on aggregation numbers of cationic micelles is determined and contrasted with the concomitant changes in pyrene diffusion.