Crystalline phases thermal behaviour and radio frequencies dielectric properties of PVDF/PEO/metal oxides hybrid polymer nanocomposite films

Hybrid polymer nanocomposite (HPNC) films of polymer blend matrix (i.e., poly(vinylidene fluoride) (PVDF)/poly(ethylene oxide) (PEO); 75/25 wt% compositional ratio) dispersed with metal oxides nanofillers (viz. Al2O3, ZnO, TiO2, or SnO2; 5 wt% amount to the PVDF/PEO blend weight) were characterized by employing differential scanning calorimeter (DSC) and broadband radio frequency impedance analyzer (RF-IA) techniques. Crystalline phases melting temperatures of the PVDF (alpha- and beta-phases) and the PEO crystallites, and their degree of crystallinity in the HPNC materials were analyzed from the DSC thermograms which were found considerably dependent on the characteristic physical properties of different nano metal oxides. The dielectric permittivity of these materials exhibited non-linear decrease with the increase of radio wave harmonic electric field frequency from 10(6) to 10(9) Hz, and it was found relatively high for the Al2O3 nanoparticles containing HPNC film. The alternating current (AC) electrical conductivity of all these HPNCs showed linear behaviour with the frequency variation and a small change for the different metal oxides nanofillers. Differences observed in the radio frequency range dielectric and electrical properties of these HPNCs were thoroughly examined with the consideration of the hybrid interfaces and interactions, and also taking into account the dielectric constant, particle size, density, and crystallinity of the nanofillers. From the experimental results, the suitability of these HPNC films as flexible nanodielectric insulators and substrates for technological advances in radio frequencies devices is conferred.