Dielectric relaxation of nonionic microemulsion: influence of the salinity

Study of dielectric properties of a quaternary microemulsion system composed of water, oil, a nonionic surfactant, and an alcohol, in the frequency range 100 kHz - 15 GHz is reported as a function of salt (NaCl) concentration. Depending on the salinity, the decomposition of the dielectric spectra shows the presence of two or three main relaxation domains. The lower relaxation frequency and the corresponding spectral amplitude increase as a function of salinity. The other observed relaxation mechanisms are shown to be dipolar in origin.