Determination of hydrodynamic radius of AOT reverse micelles prepared in near-critical propane

The fluorescence polarization technique has been applied to determine the hydrodynamic radii of water/AOT/near-critical propane micelles ranging in water to AOT molar ratio (W0) from 1 to 11 at a pressure of 15 MPa and a temperature of 310 K. The effect of pressure on hydrodynamic radius has also been investigated in the pressure range of 12–38 MPa for micelles of W0=6 and W0=9 at 310 K. 3,4,9,10-perylene sodium tetracarboxylate, solubilized within the aqueous core of the reverse micelles, was used as a fluorescent probe. The results show that the hydrodynamic radius increased significantly with increasing W0 value, but remained almost unchanged with increasing pressure.