Fabrication of flexible polymer nanocomposite films of PVDF/BaFe12O19/g-C3N4 for efficient EMI shielding in X-band frequency

Of late, synthesis and application of microwave-absorbing materials have become absolutely necessary to minimize the looming threat of electromagnetic (EM) pollution. The present study discusses the fabrication of multifunctional polymer nanocomposite films, presents the analysis of the resulting films using a polyvinylidene fluoride (PVDF) matrix with M-type barium hexaferrite (BaFe12O19) and graphitic carbon nitride (g-C3N4) fillers, and reports on their application in EM interference (EMI) shielding in the X-band (8–12 GHz) frequency range. Crystalline BaFe12O19 nanoparticles and g-C3N4 were prepared and used to fabricate PVDF/BaFe12O19/g-C3N4 composite films. The structural and compositional details of BaFe12O19 nanoparticles and the films were analyzed, along with the fraction of β-phase PVDF. The morphological, magnetic, ferroelectric, and dielectric properties of the films were studied using field emission scanning electron microscopy (FESEM), vibrating sample magnetometry, ferroelectric hysteresis, and dielectric response, respectively. In addition, the microwave absorption efficiency of the films was analyzed in the X-band frequency range with a vector network analyzer (VNA) using the waveguide technique. Magnetic loss observed in the films was due to domain wall resonance, whereas polarization, conduction, and eddy current losses were attributable to the interaction of PVDF, magnetic BaFe12O19, and semiconducting g-C3N4 fillers with the EM wave in the GHz frequency range. The VNA showed that the prepared PVDF/BaFe12O19/g-C3N4 composite films show a shielding efficiency of 99.9 %. In particular, the total shielding effectiveness (SET) of the film with 20 wt% of BaFe12O19 loading was found to be 52 dB in the X-band frequency range. Furthermore, the prepared films were flexible and showed high β fraction, saturation magnetization, and dielectric loss, along with moderate magnetic loss and high shielding efficiency, making them potential microwave absorbers in the GHz frequency region. [Display omitted] •M-type BaFe12O19 nanofiller & g-C3N4 were prepared by autocombustion and solid state reaction methods.•Polymer nanocomposite films were fabricated by incorporating BaFe12O19 and g-C3N4 with PVDF using solution casting.•Structural and compositional of the prepared materials and composite films were confirmed by XRD, FTIR analysis and morphological analysis with FESEM.•The composite films show complex dielectric loss and magnetic loss, confirmed by die