A series of novel ultra low dielectric constant soluble organic–inorganic nanocomposites in which nanoscale octa-aminophenyl polyhedral oligomeric silsesquioxanes (octaAmino POSS-Ph8) were covalently linked onto the fluoropoly(ether ether ketone)s (PEEK-CF3-COOH) were prepared and characterized. The chemical structures of the polymer matrix and nanocomposites were confirmed by 1H NMR and FT-IR spectra. The analysis of wide-angle X-ray diffraction (WAXD) and X-ray photoelectron spectra (XPS) indicated that the POSS clusters were successfully incorporated into the polymer matrix and the homogeneous dispersion of POSS cages in the polymer matrix was evidenced by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) (Si-mapping). Furthermore, the influence of the incorporation of POSS particles on the properties of nanocomposites is investigated. The dielectric constants of the organic–inorganic nanocomposites were drastically reduced relative to neat PEEK-CF3-COOH films and the dielectric constant could achieve as low as 1.71 (1 MHz). Besides, the thermal and mechanical properties of the nanocomposites were significantly improved by incorporation of octaAmino POSS-Ph8 moieties. Meanwhile, the nanocomposite thin films still retained the good transparency.
