Structural and polarization properties of polyimide/TiO2 nanocomposites

Polyimide (PI)/titanium dioxide (TiO₂) nanocomposite films were prepared by a solution mixing method with different contents of TiO₂ nanoparticles. The structural and thermal properties of pure PI and PI/TiO₂ nanocomposite films were studied by several techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermally stimulated depolarization current (TSDC). The SEM and AFM measurements show the uniform dispersion of TiO₂ nanoparticles in PI matrix, and it is also observed that the value of average roughness increases with increasing the contents of TiO₂ nanoparticles. The XRD pattern shows the presence of TiO₂ nanoparticles in PI matrix. It has been observed that the average crystallite size and percentage of crystallinity increase with content of the TiO₂ nanoparticles. FTIR spectra depict the position of different bonds in PI and nanocomposite samples. The TSDC results represent the modification of polarization phenomenon after filling of PI by titania nanoparticles.