By combining DLVO theory with the properties of chitosan microsphere, a suitable electrokinetic model was proposed, and the microscopic mechanism of interfacial polarization relaxation for concentrated suspensions was analyzed. Then dielectric measurements were carried out on concentrated suspensions of chitosan microsphere with different radius. Distinct dielectric relaxations were observed in the frequency between 10 and 100 MHz. By means of the model we proposed, the dielectric relaxation phenomena were satisfactorily interpreted and the effect of particle’s radius on interfacial polarization relaxation was discussed. The results indicated that the model is suitable for the present systems. What is more, in light of the Hanai’s method, the inner phase information of the suspensions was accurately calculated from dielectric parameters. The real time information was further analyzed to be reasonable. The results proved both experimentally and theoretically that dielectric spectroscopy is rather effective in on-line obtaining inner phase information of chitosan.

Key words: dielectric spectroscopy, chitosan microsphere, electromigration, interfacial polarization