High Dielectric and Mechanical Properties Achieved in Cross-Linked PVDF/α-SiC Nanocomposites with Elevated Compatibility and Induced Polarization at the Interface

Abstract

Remarkably improved dielectric properties including high-k, low loss, and high breakdown strength combined with promising mechanical performance such as high flexibility, good heat, and chemical resistivity are hard to be achieved in high-k dielectric composites based on the current composite fabrication strategy. In this work, a family of high-k polymer nanocomposites has been fabricated from a facile suspension cast process followed by chemical cross-linking at elevated temperature. Internal double bonds bearing poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE-DB)) in total amorphous phase are employed as cross-linkable polymer matrix. α-SiC particles with a diameter of 500 nm are surface modified with 3-aminpropyltriethoxysilane (KH-550) as fillers for their comparable dielectric performance with PVDF polymer matrix, low conductivity, and high breakdown strength. The interface between SiC particles and PVDF matrix has been finely tailored, which leads to the significantly elevated dielectric constant from 10 to over 120 in SiC particles due to the strong induced polarization. As a result, a remarkably improved dielectric constant (ca. 70) has been observed in c-PVDF/m-SiC composites bearing 36 vol % SiC, which could be perfectly predicted by the effective medium approximation (EMA) model. The optimized interface and enhanced compatibility between two components are also responsible for the depressed conductivity and dielectric loss in the resultant composites. Chemical cross-linking constructed in the composites results in promising mechanical flexibility, good heat and chemical stability, and elevated tensile performance of the composites. Therefore, excellent dielectric and mechanical properties are finely balanced in the PVDF/α-SiC composites. This work might provide a facile and effective strategy to fabricate high-k dielectric composites with promising comprehensive performance.

Enhanced dielectric properties of poly(vinylidene fluoride)–surface functionalized BiFeO3 composites using sodium dodecyl sulfate as a modulating agent for device applications

“…In case of lower SDS content PVDF‐(h‐BO) composites, the ceramics and SDS are poorly distributed that means there is an in‐homogeneous distribution of ceramics due to which more number of air voids are created. But when the SDS content increases gradually the compatibility between the polymer and ceramics also increases due to which the numbers of air voids are decreased hence, dielectric constant increases with increase in SDS content …”

Enhancing High-Frequency Dielectric Properties of Beta-SiC Filled Nanocomposites from Synergy between Percolation and Polarization

“…The lowest loss was determined at 10 vol % of SiC loading concentration for both systems, attributed to a sharp elevation of the mechanical modulus of the materials with SiC concentrations increasing from 0 vol % to 10 vol %. An increase of the modulus resulting from the introduction of hard inorganic SiC NPs could reduce ion-leakage-induced dielectric loss in polymer matrices with a relatively low modulus [ 40 ]. However, further increasing the SiC concentration (from 10 vol % to 40 vol %) would not notably enhance the modulus of composites, and it would lead to an increase of SiC/polymer interface induced polarization [ 41 ] in addition to a higher probability of percolation.…”

Achieving thermally conductive low loss PVDF-based dielectric composites via surface functionalization and orientation of SiC nanowires

“…Moreover, as a polymer material, PVDF shows the merits of good flexibility, good processability, and relatively low cost. As a result, PVDF-based dielectric nanocomposites have drawn much attention in both academia and industry on pursuing high dielectric permittivity and low loss properties for the potential applications in flexible energy storage and electronic devices [3][4][5][6].…”