REORIENTATION OF ACRIDINE-ORANGE AT LIQUID ALKANE WATER INTERFACES

The first study of a molecular reorientation at a liquid/liquid interface is described. The in-plane and out-of-plane orientational motions are investigated for acridine orange at the interface of water and several hydrocarbon liquids: n-hexadecane, isopropylcyclohexane, cis-decalin, and trans-decalin. The results reveal that the hydrocarbon viscosity has no direct influence on the in-plane reorientation of acridine orange. The results also reveal measurable differences in the out-of-plane orientational distribution, which is attributed to surface roughness. The roughness is unrelated to surface tension, suggesting that the surface roughness sensed by the probe is due to molecularity rather than to thermal capillary waves.