The Association Properties of Iodide With Cetyltrimethylammonium Bromide Micelles as Revealed by Steady-State Fluorescence Quenching Measurements

The association behaviour of I- with cetyltrimethylammonium bromide micelles was investigated by the fluorescence quenching technique with 2-(9-anthroy1oxy) palmitic acid and 12-(9- anthroyloxy) stearic acid as probes. A 1 : 1 ground-state complex occurs between I- and 12-(9-anthroyloxy) stearic acid with an equilibrium constant, Kc , of 408 dm3 mol-l. In both cases I- partitions into the micelle with a partition coefficient, Kp , of about 365. The results show the importance of probe solubilization site and probe/quencher interaction in the elucidation of micelle structure and permeability.