Synthesis, Characterization and Dielectric Properties of Rodlike Zinc Oxide-Polyimide Nanocomposites

Novel polyimide-rodlike zinc oxide hybrid nanocomposite (PI-RL-ZnO) has been developed from the poly (amic acid) with different weight percentages (1, 3, 5 wt%) of using N-methyl-2-pyrrolidone (NMP) and N, N-dimethylacetamide (DMAc) as aprotic solvents. The prepared zinc oxide-polyimide nanocomposites were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), transmission electron micrograph (TEM), X-ray diffraction (XRD) and thermal analysis (DTA/TGA/DSC) techniques. These studies showed the homogenous dispersion of zinc oxide in the polyimide matrix with an increase in the thermal stability of the composites on zinc oxide loadings. More importantly, we intend to explore the possibility of incorporating ZnO particles through dispersion into the polyimide network to achieve the polyimide hybrid with lower dielectric constant (low-k). The lowest dielectric constant achieved of the PI-RL-ZnO material is 2.82 by incorporating 5 wt% ZnO (pure PI, k = 3.22). The reduction in the dielectric constants of the PI-RL-ZnO hybrids can be explained in terms of creating ZnO particles and the free volume increase by the presence of the ZnO particles resulting in a loose PI structure.