In this paper, the composites of polyvinylidene fluoride (PVDF)/nickel (Ni) prepared through simple blending and hot-molding process have been investigated for dielectric, electromagnetic shielding, and radar absorbing properties. In order to study complex permittivity of the composites in 40 Hz–20MHz frequency range, impedance spectroscopy (IS) technique is used. Besides, the complex permittivity and permeability in addition to shielding effectiveness (SE), reflection coefficient (backed by air), and loss factor are calculated using scattering parameters measured in X-band (8.2–12.4 GHz) by waveguide method. Further, in X-band, a theoretical analysis of single layer absorbing structure backed by perfect electrical conductor is then performed. A flanged coaxial holder has also been designed, fabricated, calibrated, and tested for electromagnetic interference SE measurement in the broad frequency range (50 MHz–18 GHz). The IS results indicate large enhancement in dielectric constant as a function of Ni loading in the polymer-metal composite (PMC) phase. This result has been explained using interfacial polarization and percolation theory. The frequency dependent response of ac conductivity has been analyzed by fitting the experimental data to the “Johnscher’s universal dielectric response law” model. The results obtained for SE (in X-band over broad frequency range) and reflection coefficient indicate that PVDF/Ni composites give better electromagnetic interference shielding and radar absorption properties at filler concentration (fcon)fc in the PMC, whereas at fc<fcon, the charge storage mechanism dominates in the insulator regime of the composite phase. Therefore, the range of PMC compositions below and above percolation threshold has been observed to have different variety of applications.

The analysis of an orthoconic antiferroelectric liquid-crystalline mixture, using dielectric spectroscopy, has revealed a plurality of ferroelectric smectic C* subphases. A great variety of relaxation responses that could indicate the presence of different SmC* subphases has been observed with the differential scanning calorimetry (DSC) technique in partial agreement with other techniques as DSC and optical microscopy. They represent smectic intermediate variants between the ferroelectric phase and the antiferroelectric one, whose study is still open and is collecting a lot of interest in academic field. The results obtained by dielectric spectroscopy were compared with other techniques as differential scanning calorimetry and polarized optical microscopy. The results demonstrate the possibility of using dielectric spectroscopy to highlight subphases that cannot be observed with conventional experimental techniques.