Zr doped Barium hexaferrite nanoplatelets and RGO fillers embedded Polyvinylidenefluoride composite films for electromagnetic interference shielding applications

Abstract

In this study, we investigate the effect of M-Type zirconium doped barium hexaferrite nanoparticles addition with reduced graphene oxide (RGO) fillers in Polyvinylidenefluoride (PVDF) matrix to design lightweight and flexible polymer composite films for electromagnetic wave absorption and electromagnetic interference (EMI) shielding. Firstly, Zr doped M-Type barium hexaferrite (BaZrFe11O19) nanoparticles were prepared by sol-gel auto-combustion method and RGO by modified Hummers' method followed by thermal reduction process. PVDF/RGO/BaZrFe11O19 composite films were fabricated using simple solvent casting method. The resultant samples were investigated using various instruments including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman Spectroscopy, High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and Vibrating sample magnetometer (VSM) analysis. The EMI shielding effectiveness (SE) of PVDF/RGO/10 wt% BaZrFe11O19 composites films is higher than that of PVDF/RGO/30 wt% BaZrFe11O19 composites in the X-band (8.2 GHz −12.4 GHz) frequency. Inclusion of BaZrFe11O19 nanoplatelets and conductive RGO fillers in the polymer PVDF matrix enhances shielding by conquered absorption with less reflection. The shielding mechanism suggests that in addition to conducting and magnetic losses due to RGO and BaZrFe11O19 respectively, the synergetic effect among RGO, BaZrFe11O19 and PVDF supports shielding by input impedance matching to that of free space, multiple internal reflections from BaZrFe11O19 and subsequent absorption by RGO, eddy current losses, dielectric losses, interfacial polarization losses, and so on. The resultant flexible films show an excellent EMI shielding efficiency (EMI SE) of 48.59 dB at 11.1 GHz for 10 wt% BaZrFe11O19 addition in polymer composite for a very small thickness of 0.2 mm. The higher dielectric loss (tanδε = 1.67) and magnetic loss (tanδμ = 0.41) contribute to the microwave absorption value of 40.98 dB (>99% attenuation) and are found to decrease with the amount of ferrite nanofillers. These results demonstrate that RGO and minimum amount of M-Type doped barium hexaferrite nanofillers embedded with polymer composite films could be one of the promising EMI shielding materials for RADAR and military applications.