Achieving Enhanced Interfacial Interaction and High Dielectric Properties in PVDF Composite Film Containing Polyaniline-Derived N-Doped Carbon

Abstract

Adding conductive fillers to the polymer matrix is one of the most common methods to prepare composite films with a high dielectric constant. However, it needs complicated procedures to improve the incompatibility of conductive fillers with the matrix; otherwise, high dielectric loss would be caused in the composite system. Herein, the N-doped carbon (NC) facilely prepared by the carbonization of polyaniline was used as the conductive filler, and poly(vinylidene fluoride) (PVDF) was employed as the matrix, to produce a composite film with high dielectric properties for the first time. The result shows that the NC fillers prepared at 600 °C (denoted as NC600) could bring about the best dielectric property in PVDF composite film; for instance, as the NC600 content is 6 wt %, the high dielectric constant of NC600/PVDF is 27 (3.1 times that of pure PVDF) with low dielectric loss of 0.091 at 1 kHz. The study of FT-IR, XRD, DSC, AFM, and SEM demonstrates that the NC600 filler could introduce the transformation of PVDF from the α to β phase and achieve satisfactory compatibility and dispersion in the PVDF matrix, which should be attributed to the enhanced interfacial interaction between pyrrolic-N (NC600) and −CF2 (PVDF) within the composite system. This work provides an effective strategy to manufacture PVDF composite films with high dielectric properties and low cost, showing great value for both theory and practical applications.