Giant Dielectric Permittivity Nanocomposites: Realizing True Potential of Pristine Carbon Nanotubes in Polyvinylidene Fluoride Matrix through an Enhanced Interfacial Interaction

TLDR

Carbon nanotubes have unprecedented electronic properties and large specific areas as nanoscale fillers, but their potential has not been fully realized in polymer composites due to poor dispersion and weak interfacial interaction. The study aims to develop a robust, simple procedure to create polymer composites with strong interfacial interaction by melt‑mixing pristine multiwalled carbon nanotubes into poly(vinylidene fluoride). The method uses melt‑mixing pristine MWNTs into PVDF to achieve molecular‑level interfacial interaction. Raman spectroscopy confirms the interfacial interaction and the formation of a thin PVDF layer on MWNTs, yielding a nanocomposite with a giant dielectric permittivity of 3800—three orders of magnitude higher than PVDF—while maintaining low conductivity (6.3 × 10⁻⁵ S m⁻¹) and excellent thermal stability, attributed to a reinforced Maxwell–Wagner–Sillars effect.

Abstract

Carbon nanotubes have unprecedented electronic properties and large specific areas as nanoscale fillers, but their potential has not been fully realized in polymer composites due to the poor dispersion and weak interfacial interaction. Here, we present a robust and simple procedure to prepare polymer-based composites with a remarkable molecular level interaction at interfaces through melt-mixing pristine multiwalled carbon nanotubes (MWNTs) within poly(vinylidene fluoride) (PVDF) matrix. The interfacial interaction is confirmed by Raman spectroscopy as well as the formation of much thin PVDF layer on individual MWNT. The resultant nanocomposite with a huge interfacial area possesses a giant dielectric permittivity (3800) of 3 orders of magnitude higher than the PVDF matrix, while retaining a low conductivity level (6.3 × 10−5 S.m−1) and an excellent thermal stability. These results could be explained by a reinforced Maxwell−Wagner−Sillars (MWS) effect based on the remarkable molecular level interaction.