On the absorption dominated EMI shielding effects in free standing and flexible films of poly(vinylidene fluoride)/graphene nanocomposite

The present work highlights the remarkably high electro-magnetic interference (EMI) shielding effectiveness of about 47 dB, exhibited by highly conducting and ordered poly(vinylidene fluoride) (PVDF)/graphene nano composite films of thickness around 20 pun, in the microwave frequency range 8-12 GHz, obtained by solution casting method. The films were characterized structurally using X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy and the analysis indicates the enhancement in the highly ordered beta phase of PVDF with the incorporation of graphene. In the entire frequency range of analysis, by absorption loss to the total EMI shielding effectiveness is very high compared to that by reflection loss. The high electrical conductivity of the composite films promotes shielding by absorption losses which is of ample significance in stealth applications. The present results identify the PVDF/graphene nanocomposite film as an effective, lightweight, free standing, flexible, mechanically and thermally stable, absorption dominated EMI shielding material with application prospects in a broad range of electromagnetic spectrum. The shielding effectiveness of these highly conducting nanocomposite films, far exceeds most of the previously reported values and meets the commercial requirements. The freestanding and flexible nature of these films facilitates EMI shielding applications without the geometrical constraints of the shape or size of the object.