Da. Piasecki et Mj. Wirth, REORIENTATION OF ACRIDINE-ORANGE IN A SODIUM DODECYL-SULFATE MONOLAYER AT THE WATER HEXADECANE INTERFACE, Journal of physical chemistry, 97(29), 1993, pp. 7700-7705
A macroscopically oriented layer of sodium dodecyl sulfate (SDS) at th
e interface of water and n-hexadecane was investigated using acridine
orange as a fluorescent probe. The range of angles through which the h
indered out-of-plane reorientation occurs for the probe was found to c
orrespond closely to the surface roughness predicted by the capillary
wave model through the interfacial tension. The in-plane reorientation
of the probe was found to be significantly slower than that in the ab
sence of SDS, with little dependence on the SDS concentration. The in-
plane and out-of-plane rotations of acridine orange appear to correspo
nd to the two decay components measured for acridine orange in micella
r solution, indicating that these macroscopically oriented surfactant
monolayers can provide detailed insight into solute-micelle interactio
ns. For SDS micelles, the behavior of the oriented interface suggests
that the surfactants are aggregated with the probe in the micelle and
that the SDS micellar surface is very rough.