ELECTRIC BIREFRINGENCE RELAXATION SPECTROSCOPY OF LINEAR MICELLES IN AQUEOUS CETYLTRIMETHYLAMMONIUM BROMIDE SOLUTIONS WITH SODIUM-SALICYLATE

The influence of sodium salicylate (NaSal) concentration on the linear micelle formation in an aqueous solution of cetyltrimethylammonium br omide (CTAB) is investigated by the frequency-domain electric birefrin gence relaxation spectroscopy (FEB method). The contour length L of li near micelles is found to increase with increasing NaSal concentration . C-s but for further increase of C-s in excess of the CTAB concentrat ion, L decreases, i.e., linear micelles break into shorter pieces. The FEB result indicates also that the diffusion constant of salicylate i ons bound to a linear micelle is nearly independent of C-s with an ave rage value smaller than that of free salicylate ions. (C) 1996 America n Institute of Physics.