Abstract:

The dielec. behavior of a microemulsion prepd. from dodecane, butanol, H2O and polyoxyethylene (10) oleyl alc. (Brij 97) was studied by time domain dielec. spectroscopy over the frequency range 105-1010 Hz for temps. between 10 and 40° with varying H2O content. Several dielec. dispersion regions with the typical characteristic relaxation times of the order of nanoseconds and tens of picoseconds are obsd. They are analyzed in time domain in terms of macroscopic dipole correlation functions and are attributed to the relaxation mechanisms of the different chem. compds. within the microemulsion. The appearance and intensity of the peaks for the relaxation processes depend on the H2O content. The types of motion of different kinetic units that can be manifested as local relaxation processes are proposed. The dielec. properties of microemulsions depend on the underlying phase behavior and on the consequent morphol. in these systems. The results suggest that changes in the microstructure of polarization and relaxation mechanisms occur in the H2O fraction content intervals of 5-10, 10-35, and 35%. [on SciFinder(R)]