Enhanced dielectric properties of PVDF polymer nanocomposites: A study on gold−decorated, surface−modified multiwalled carbon nanotubes

The integration of surface-modified multiwalled carbon nanotubes ( f MWCNTs) into polymer nanocomposites has been extensively studied for their potential to enhance dielectric properties. This study, however, pioneers the use of a novel hybrid filler comprising f MWCNTs coated with metal nanoparticles, specifically aimed at augmenting the dielectric performance of polymers. In our research, poly(vinylidene fluoride) (PVDF) nanocomposite films were synthesized using f MWCNTs with a diameter of ∼6–9 nm and a length of 5 μm, adorned with gold nanoparticles ( n Au) of ∼5.4 ± 0.9 nm via an adapted Turkevich method. Comprehensive analyses were conducted on n Au− f MWCNTs hybrid powder and their nanocomposites in PVDF with varying filler concentrations, confirming the formation of n Au− f MWCNTs with a weight ratio of 1.1 : 98.9. Three−phase percolative nanocomposites were produced by dispersing the hybrid filler in N , N −dimethylformamide, facilitated by interactions between the negative charge of n Au−fMWCNTs (zeta potential of ∼ −40.43 ± 0.46 mV) and polar phases of PVDF. This was verified through zeta potential and Fourier−transform infrared spectroscopy analyses. The dielectric permittivity ( ε ′) of the nanocomposites significantly increased from 17.8 to 524.8 (at 1 kHz) with filler loadings from 0.005 to 0.01 vol%, while the dielectric loss tangent (tanδ) showed a minor increase from 0.05 to 1.18. These enhancements are attributed to the elevated permittivity of n Au− f MWCNTs hybrid powder, PVDF's transition to the β−phase, and interfacial polarization effects. The restrained growth of n Au on f MWCNTs and the inhibition of conductive pathways in the polymer matrix contributed to the low tanδ values.