REORIENTATION OF ACRIDINE-ORANGE AT AN ALCOHOL-MODIFIED LIQUID LIQUIDINTERFACE/

The in-plane and out-of-plane reorientation of a fluorescent probe, ac ridine orange, was studied at the water/hexadecane interface, to which varying amounts of short-chain alcohols were adsorbed. The in-plane r eorientation was affected little by the addition of these alcohols. Th e out-of-plane reorientation behavior revealed that the probe has a wi der orientational distribution than that predicted from the interfacia l tension by the capillary wave model. The interpretation is that both surface roughness and the intrinsic out-of-plane rotation of the prob e contribute to the overall orientational distribution. The behavior o f the fluorescent probe at the alcohol-modified water/hexadecane inter face contrasts with that of the same interface modified by a charged s urfactant.