PHOTOISOMERIZATION NEAR A HYDROPHOBIC SURFACE - DIETHYLOXADICARBOCYANINE IODIDE IN A REVERSE MICELLE

A picosecond study indicates that inside the water pool of the aerosol -OT (AOT) microemulsion in n-heptane the photoisomerisation of 3,3'-di ethyloxadicarbocyanine iodide (DODCI) is nearly three times slower com pared to that in ordinary water. The slower isomerisation at the AOT-w ater interface implies greater friction experienced by DODCI compared to bulk water and is attributed to the electrostatic attraction betwee n the DODC cation and AOT anion. This is in sharp contrast to the thre efold faster photoisomerisation of DODCI at the air-water interface co mpared to bulk water. (C) 1997 Elsevier Science B.V.