OPTICAL MATCHING PHENOMENON IN WATER-OIL MICROEMULSIONS

Optical matching phenomena were observed with water/AOT/isooctane (W/O) microemulsions. The phenomenon has been interpreted on the basis of Rayleigh's scattering theory in combination with a quantitative relation between the macroscopic dielectric constant of the microemulsion and the dielectric properties of its constituents. A residual scattering contribution at the left bracket H//2O right bracket / left bracket AOT right bracket -ratio, where the system meets the optical matching condition, could be very satisfactorily assigned to density fluctuations of the surfactants in the water/oil-interface, hence explaining the apparent polydispersity of these microemulsions.