Dielectric Properties and AC Conductivity of Chitosan-La2O3 Nanocomposite.

In this study, polymeric films based on chitosan (CS) doped with Lanthanum oxide nanoparticles at different weight percentages (5, 10, 15, and 20% La2O3/CS) were prepared using the simple solution cast transformation. The dielectric constant increases with increasing the La2O3 content, and this could be attributed to the induced defects, as a result more dipoles are produced in the polymer matrix. Also, the values of Z′ and Z″ increase with La contents. On other hand, we noticed that the plot of the normalized-imaginary electric modulus versus the frequency shows a clear peak at high frequency for all samples. This peak is associated with ionic conduction. The AC conductivity increased by increasing the La2O3 content. Furthermore, AC conductivity increases with frequency because the absorbed energy from the electric field can increase the number of charge carriers that are participating in the electric conduction. Moreover, the values of the universal exponents were larger than the unity and increase with increasing temperatures which means that the conduction process may be pertinent to reorientational (or localized) mechanism. [ABSTRACT FROM AUTHOR]