Effect of secondary filler properties and geometry on the electrical, dielectric, and electromagnetic interference shielding properties of carbon nanotubes/polyvinylidene fluoride nanocomposites

Hybrid polymer nanocomposites based on polyvinylidene fluoride (PVDF) as the matrix, carbon nanotubes (CNTs) as the primary conductive filler, and metal nanoparticles as secondary fillers were fabricated by melt mixing. Secondary nanofillers with different geometry and properties (nickel nanowire (NiNW), silver nanowire (AgNW), nickel nanoparticle (NiNP), and silver nanoparticle (AgNP) were selected to investigate the effect of geometry and properties of secondary filler on the hybrid polymer nanocomposites' properties. Electrical conductivity, electromagnetic interference (EMI) shielding effectiveness, and complex microwave properties of the fabricated hybrid nanocomposites were studied in X-band frequency (8.2-12.4 GHz). The hybrid nanocomposites containing CNT/AgNW demonstrated superior conductivity and EMI shielding compared to individual fillers such as CNT, AgNW, NiNW, AgNP, NiNP, or hybrid system such as CNT/NiNW. The novelty of the present study lies in the unique synergy arising from the combination of nanofillers with similar geometry and high electrical conductivity, which resulted EMI shielding effectiveness as high as 27 dB for a shield with only 1.1 mm thickness. The EMI shielding mechanisms, including negative permittivity were studied and explained in details in the manuscript.

Automated summary

Hybrid polymer nanocomposites based on PVDF matrix with different secondary nanofillers were fabricated and studied for their electrical conductivity and EMI shielding effectiveness. The hybrid nanocomposites containing CNT/AgNW showed superior performance compared to individual fillers, with an EMI shielding effectiveness as high as 27 dB for a shield with only 1.1 mm thickness. Various EMI shielding mechanisms, including negative permittivity, were studied in detail.