Role of Electrical Conductivity in the Shielding Effectiveness of Composite Polyvinyl Alcohol/Multiwall Carbon Nanotube Nanofibers for Electromagnetic Interference Applications

The shielding effectiveness (SE) against the electromagnetic interference (EMI) of polyvinyl alcohol/multiwall carbon nanotubes (PVA/MWCNTs) composite nanofibers is characteristic of higher absorptivity of the radiation that enhances with the increasing concentration of MWCNTs content in these composites. However, by enriching the content of conductive fillers (MWCNTs), the conductivity of the composites is also stirred up. Concomitantly, the conductivity of these composites contributes toward the reflectivity of the EM radiation from them. Certain applications of the EMI shielding material require a lower level of reflectivity of the EM radiation. This study intends to see how SE of the PVA/MWCNTs composite nanofibers is affected vis-a-vis their conductivity for S-band radiation. Samples of nanofibers, with (5, 10, 15, and 20) wt % of MWCNTs loading in 10 wt % of PVA solution, were prepared through electrospinning and studied for their electrical conductivity and EMI SE. It is observed that by increasing the content of MWCNTs in PVA solution from 5 to 20 wt % the conductivity of the composites tends to increase from 21 to 866 times that of PVA, while the SE increases from 10 db to 25 db over the S-band range of frequencies.