Bimolecular Fluorescence Quenching Reactions in Didodecyldimethylammonium Bromide and Chloride Vesicles and Micelles

Fluorescence decays have been measured for pyrenesulfonate (PyS^?) in the presence of anthraquinone-1-sulfonate (AQ1S^?), for pyrene (Py) at various concentrations, and Py in the presence of AQ1S^? in 5 mmol·dm^?3 didodecyldimethylammonium bromide (DDABr) vesicle solutions. Reaction rate constants were found to increase in the order Py*–Py < PyS^?*–AQ1S^? < Py*–AQ1S^?. Fluorescence decays have also been measured in 5 mmol·dm^?3 didodecyldimethylammonium chloride (DDACl) solutions; the results showed micellar solution behavior, and micellar aggregation numbers and quenching rate constants were obtained. The quenching rate constants in vesicles and micelles were converted to the two dimensional rate constants having the same units. Two dimensional diffusion coefficient and reaction distance were obtained for the PyS^?*–AQ1S^? system on the DDABr vesicle surface.