Nonexponential relaxations in dense microemulsion near the glasslike transition

Extensive quasielastic-light-scattering, small-angle neutron scattering, and neutron-spin-echo (NSE) spectroscopic measurements have been performed on a three-component microemulsion system containing bis(2-ethylhexylsulfosuccinate) (AOT) (surfactant), ${\mathrm{D}}_2$O, and decane (oil) at two temperatures in the one-phase region. By fixing the molar ratio of water to AOT at w=40.61, the average radius of spherical surfactant coated water droplets can be maintained at 58 Å with a polydispersity index of 22%. The volume fraction φ of the droplets can be continuously varied from 0.1 to 0.75, spanning the entire range from the dilute gas all the way to the close-packed glass by adjusting the oil content of the microemulsion. The static structure factors and the time-dependent density correlation functions of these densely packed spherical droplets were systematically measured as a function of the volume fraction.