Poly (vinylidene fluoride) (PVDF) is mixed with custom-synthesized carbonaceous nanomaterials at various loadings to create polymer nanocomposites for electrical applications. To achieve this, different types of nanofillers (carbon nanotube (CNT), graphene oxide (GO), and reduced graphene oxide (RGO)) are used to prepare the conductive nanocomposites at various loadings (0.1, 0.3, 0.5, 1.0, 2.0, and 3.0wt.%) via solution mixing technique. To evaluate the effect of the fabrication technique, melt mixed CNT-based polymer nanocomposites are also produced. Hence, we were able to study the effects of mixing protocol, nanofillers' geometry, and nanofillers' surface chemistry on the final properties of conductive polymeric nanocomposites. It was shown that the elimination of oxygen-containing functional groups of GO considerably enhances the electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) from 0.3S/m and 4dB for GO/PVDF to 10S/m and 14dB for RGO/PVDF nanocomposite, respectively. However, the melt mixing method's CNT/PVDF nanocomposites showed the highest electrical conductivity and EMI SE among all the samples, signifying the importance of nanofiller geometry on final properties of conductive polymer nanocomposites. In the next step of this work, magnetic nanoparticle-based polymeric composites were prepared to fabricate sandwich-like structured nanocomposites with enhanced EMI SE. Ni/PVDF and Fe3O4/PVDF nanocomposite are used as adsorbing layers to tune the samples' EMI shielding mechanism. We were able to significantly improve the total EMI SE of the multi-layered samples by improving the adsorption mechanism. Interestingly, the total EMI SE and shielding mechanism was dependent on the layers' order. The best results were achieved when the magnetic layer was placed in between two highly conductive layers, e.g., CNT/PVDF. Hence, the order of nanocomposites' layers and the interactions between them strongly affects the overall shielding effectiveness of the multilayer nanocomposite.

Electromagnetic interference (EMI) shielding properties of single-layer and multilayer PVDF-based carbonaceous nanocomposites

ACS Spring Meeting 2021

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