Enhancing Dielectric Properties of Gold Nanoparticles Attached to Acid-Treated Pristine Multiwalled Carbon Nanotubes-BaTiO₃/PVDF Polymer Nanocomposites

Improving the properties of polymer matrix nanocomposites, such as increasing dielectric permittivity, reducing the loss tangent, and minimizing filler content, is essential for modern electronics applications. In this work, we successfully prepared gold nanoparticles (nAu) attached to acid-treated pristine multiwalled carbon nanotubes (nAu-ACNTs) combined with BaTiO₃/poly(vinylidene fluoride) (nAu-ACNT- BT/PVDF) polymer nanocomposites with different loading volume fractions of nAu-ACNT (f_nAu-ACNT) and a fixed BT content of 2 vol%. The ACNTs used had a particle size of approximately 6–9 nm in diameter and 5 μm in length, while the nAu attached to the surface of ACNTs had an average size of ~ 5 nm. The BT particles had a size of around 100 nm. The morphology, microstructure, crystal structures, phase composition, and dielectric properties of the polymer nanocomposites were investigated. Notably, the dielectric permittivity of the nAu-ACNT-BT/PVDF nanocomposite with f_nAu-ACNT = 0.010 was as high as ~ 814.2 (at 25 °C and 1 kHz), which is ~ 75 times higher than that of pure PVDF polymer (ε′ = 10.8). Under these conditions, the dielectric loss tangent was maintained at a low value of tanδ ~ 0.478, whereas tanδ of the nanocomposite without nAu nanoparticles at the same total volume fraction was 122.95. The enhanced dielectric properties of the nAu-ACNT-BT/PVDF nanocomposite may be attributed to interfacial polarization and the inhibition of conductivity paths of ACNTs in the polymer matrix.