Abstract: Comparative study on the water-soluble photosensitizors, benzoylbenzyl sodium sulfonate (BP^-) and benzoylbenzyl trialkylammonium bromide (BP⁺) with benzophenone (BP) was carried out. The results of the transient and steady spectra indicate that both BP⁺ and BP^- locate in the stern layers of SDS anionic micelle and of CTAB cationic micelle respectively. Their photopysical and photochemical properties in homogeneous and heterogeneous systems are the same as that of BP. The photoreduction rates in the different ionic micellar systems were measured. The results obtained show that the photochemical reactivities of both ionic benzophenones BP⁺ and BP^- are much higher than that of neutral BP. Their photoreduction rates in the different ionic micellar systems are queit different due to the static electric interaction. Under the appropriate condition, the photoreduction rates of the ionic BP⁺ and BP^- are decades higher than that of neutral BP. The hydrophobic effect of amines was also examined.

Key words: water-soluble photosensitizoT, micelle, photoreduction