Poly Vinylidene Fluoride Composites Research Articles

Development of non-oxidized graphene flakes (NOGF)/polyvinylidene fluoride (PVDF) composites for high-performance EMI shielding efficiency

As numerous communication devices use multiband electromagnetic waves in modern society, electromagnetic interference (EMI) shielding materials become increasingly important due to the harmful effects of electromagnetic waves. While metal-based materials have shown high shielding performance, they have many drawbacks such as high density, high processing cost, and low corrosion resistance. Conductive polymer composites (CPCs), which can overcome these shortcomings of metal-based materials, have become increasingly popular in recent years. In this study, non-oxidized graphene flakes (NOGFs) are synthesized by exfoliating the ternary graphite intercalant compound (t-GIC) and used as fillers for CPCs. The electrical conductivity and EMI shielding effiency (SE) of NOGF/polyvinylidene fluoride (PVDF), graphite/PVDF and reduced graphene oxide (rGO)/PVDF composites are investigated. NOGF/PVDF composites showed notably enhanced electrical conductivity and EMI SE than the others. This is mostly due to the non-oxidative fabrication method that does not destroy the sp2 structure of graphene sheet, thus preserving the unique electrical properties of graphene.

Preparation of dopamine/L-cysteine modified PVDF composite membrane and its application in the removal of mercury ions from water

Polyvinylidene fluoride (PVDF), embodying a stabilization under thermal environment and capability to resist chemical corrosion, is widely used as a membrane-forming material. However, its inherent hydrophobicity and lack of active functional groups in the structure limit its suitability for adsorption applications. In this study, PVDF-based membranes were first prepared by the non-solvent phase inversion method, and then, polydopamine (PDA) was coated on these membranes by the oxidative self-polymerization of dopamine (DA). Then, L-cysteine (LCys) was grafted by self-assembly to obtain a highly hydrophilic PVDF composite (PVDF@PDA-LCys) membrane with excellent ability for Hg(II) ion capture. The membrane has the following characteristics: excellent hydrophilicity, with a water contact angle (WCA) that drops to 0° within 3 s, which is far superior to the 89.22° WCA of the PVDF-based membrane. Given an 10 mg·L−1 initial concentration of Hg(II), adsorption experiences 120 min, the removal efficiency reaches 95.14%. The fitted maximum adsorption capacity is 97.98 mg·g−1. Additionally, the composite membrane exhibits good acid resistance. When the solution pH is as low as 1.5, the Hg(II) ion removal efficiency is still close to 70%. The performance of the composite membrane remains stable after repeated use. This study demonstrates an environmentally friendly and practical method for preparing PVDF-based composite membranes with potential applications in wastewater treatment.

Dielectric thermally conductive boron nitride/silica@MWCNTs/polyvinylidene fluoride composites via a combined electrospinning and hot press method

With the development of microelectronics towards integration, miniaturization and high power, the accumulation of heat in this small space has become a serious problem. Therefore, polymer matrix composites with high thermal conductivity and electrical insulation need to be developed urgently. Here, an ordered oriented boron nitride/silicon dioxide (silica) coated multiwalled carbon nanotubes (BN/SiO2@MWCNTs) thermally conductive network was constructed in a polyvinylidene fluoride (PVDF) matrix by electrostatic spinning technique, and subsequently the PVDF composites were prepared by hot-pressing. The synergistic effect of two-dimensional BN and one-dimensional MWCNTs in PVDF was investigated. It was found that the out-of-plane thermal conductivity of BN30/SiO2@MWCNTs composites reached 0.4693 Wm−1 K−1, which was 209% higher than that of pure PVDF and 10% higher than that of BN/PVDF composites. The in-plane thermal conductivity of BN30/SiO2@MWCNts) composites reached 1.5642 Wm−1 K−1, which was 1055% higher than pure PVDF and 40% higher than BN/PVDF composites. This is attributed to the synergistic effect of BN on SiO2@MWCNTs. Meanwhile, the volume resistivity and breakdown strength of the BN/SiO2@MWCNTs/PVDF composites reached 3.6 × 1013 Ω m and 47.68 kV/mm, respectively. The results indicate that the BN30/SiO2@MWCNTs/PVDF composites have excellent thermal conductivity and electrical insulating properties, which are promising for microelectronics applications.

Enhancing dielectric properties and energy storage performance of polyvinylidene fluoride composite by surface‐modified AgNbO3 nanoparticles

Enhancing dielectric properties and energy storage performance of polyvinylidene fluoride composite by surface‐modified AgNbO₃ nanoparticles

Synergistic terahertz shielding effects of electrically conductive MXene and shape-controlled magnetic nickel in polyvinylidene fluoride (PVDF) composites

Terahertz (THz) shielding materials have garnered significant attention due to various potential applications in wireless communication, sensing, and defense. In this study, we present efficient THz shielding performance of polyvinylidene fluoride (PVDF) polymer composites incorporated with a mixture of MXene and shape-controlled nickel (Ni) nanoparticles. The PVDF/MXene/Ni composites demonstrated exceptional absorption coefficient and shielding effectiveness against unwanted THz electromagnetic waves, owing to the remarkable synergistic effect between electrically conductive Ti3C2Tx MXene and magnetic nickel nanoparticles. Notably, magnetic properties of Ni nanoparticles were controlled by external magnetic field applied during the synthesis process. Flower-like Ni nanoparticles synthesized under an external magnetic field exhibited enhanced magnetic properties compared to spherical Ni nanoparticles synthesized without an external field. As a result, a 20-µm thick PVDF/MXene/Ni composite film, with a 10 wt.% loading of flower-like Ni nanoparticles, demonstrated the THz shielding effectiveness of 34 dB at 1 THz. This shielding performance surpasses those of composite containing spherical Ni nanoparticles (26.7 dB) as well as previously reported shielding materials. These findings highlight an effective approach to tailor the THz shielding properties of polymer composites by modifying the composition and morphology of conductive and magnetic fillers.

Photoinduced charge generation of nanostructured carbon derived from human hair biowaste for performance enhancement in polyvinylidene fluoride based triboelectric nanogenerator

Carbon nanostructures derived from human hair biowaste are incorporated into polyvinylidene fluoride (PVDF) polymer to enhance the energy conversion performance of a triboelectric nanogenerator (TENG). The PVDF filled with activated carbon nanomaterial from human hair (AC-HH) exhibits improved surface charge density and photoinduced charge generation. These remarkable properties are attributed to the presence of graphene-like nanostructures in AC-HH, contributing to the augmented performance of PVDF@AC-HH TENG. The correlation of surface morphologies, surface charge potential, charge capacitance properties, and TENG electrical output of the PVDF composites at various AC-HH loading is studied and discussed. Applications of the PVDF@AC-HH TENG as a power source for micro/nanoelectronics and a movement sensor for detecting finger gestures are also demonstrated. The photoresponse property of the fabricated TENG is demonstrated and analyzed in-depth. The analysis indicates that the photoinduced charge carriers originate from the conductive reduced graphene oxide (rGO), contributing to the enhanced surface charge density of the PVDF composite film. This research introduces a novel approach to enhancing TENG performance through the utilization of carbon nanostructures derived from human biowaste. The findings of this work are crucial for the development of innovative energy-harvesting technology with multifunctionality, including power generation, motion detection, and photoresponse capabilities.

Preparation and properties of polyvinylidene fluoride dielectric nanocomposites for energy storage applications through synergistic addition of ionic liquid‐modified graphene oxide nanosheets and functionalized barium titanate hybrid fillers

AbstractTo tackle the challenge of filler agglomeration and low interfacial bonding strength during manufacturing filled polymer dielectric nanocomposites containing graphene oxide (GO) nanosheets, the author proposed an interface design strategy based on the synergistic hybridization of ionic liquid (IL) modification and different dimensional fillers. GO nanosheets were functionalized by IL, and then polyvinylidene fluoride (PVDF) dielectric nanocomposites (GO‐g‐IL/PVDF) were prepared and evaluated. Based on this, hydroxylated barium titanate BT‐OH@GO‐g‐IL/PVDF ternary nanocomposites were further prepared. A comprehensive analysis of the morphology, mechanical, thermal, electrical, and dielectric properties of the PVDF dielectric nanocomposites was systematically conducted. The results showed that IL was successfully grafted on GO, benefiting an increase in the filler dispersion and interfacial bonding strength. GO‐g‐IL also promoted β‐crystal formation of PVDF and increment of crystallinity. DSC test further revealed that the inclusion of BT‐OH@GO‐g‐IL as dielectric nanofillers promoted the formation of multiple crystal types in PVDF and accelerated the crystallization process. The incorporation of GO‐g‐IL facilitated the formation of localized conductive networks within the PVDF matrix, leading to enhanced electronic displacement polarization and an improved dielectric constant. The dielectric constants of the GO‐g‐IL/PVDF composites containing 2% and 8% of GO‐g‐IL were measured to be 24.28 and 78.46, which were found to be 2.6 and 8.4 times higher than that of pure PVDF. However, the dielectric loss also increased sharply at high nanofiller loading. The dielectric constant and loss of the BT‐OH@GO‐g‐IL/PVDF nanocomposites were found to be 40.32 and 0.38, with a content of 2% for GO‐g‐IL and 20% for BT‐OH.Highlights A facile interface design strategy based on ionic liquid (IL) integrating GO nanosheets and hydroxylated barium titanate (BT‐OH) to form BT‐OH@GO‐g‐IL compounding nanofiller has been proposed. PVDF dielectric nanocomposites containing BT‐OH@GO‐g‐IL compounding nanofiller were systematically investigated and compared. The effects of interfacial interactions between BT‐OH@GO‐g‐IL and PVDF contribute to the uniform dispersion and comprehensive property improvements of PVDF dielectric nanocomposites. This work provides a novel strategy for the fabrication of PVDF dielectric nanocomposites, inspiring the research and development of PVDF in the energy storage applications areas in the future.

Effect of meta-structure on mechanical properties of polyvinylidene fluoride composite-based 3D printed intramedullary pins

Some studies have outlined the use of 3D-printed polyvinylidene fluoride (PVDF) composite-based solid intramedullary (IM) pins with tunable mechanical (tensile, compressive, flexural, and torsional) properties for orthopedic applications. But hitherto little has been reported on the effect of meta-structure induced in 3D-printed IM pins for canines from the mechanical properties’ viewpoint. This study highlights the design, fabrication, and testing to mimic actual loading conditions in the canine femur bone on novel IM pin with meta-structure employed in different length zones (30%, 40%, and 50% of total gauge length) prepared by fused filament fabrication (FFF) of PVDF composite. The IM pin (of length 150 mm) has square threads (pitch 2 mm) at the distal end (ɸ7 mm, up to 60 mm in length), and V threads (pitch 1.5 mm) at the proximal end (ɸ6 mm, up to 30 mm in length). The IM pin was fabricated at the best setting (of the FFF process) suggested by the multifactor optimization (at nozzle temperature (Nt) 235°C, printing speed (Ps) 60 mm/s, and raster angle (RA) 45°). The result suggests that for the solid IM pins prepared at the optimized settings the observed elongation, peak load (PL), and break load (BL) during tensile and compressive loading were 4.83 mm, 968.40 N, 958.20 N, and 14.19 mm, 412.80 N, 371.52 N respectively. Whereas for 50% meta-structure the observed elongation, PL, and BL during tensile and compressive loading were 14.49 mm, 405.49 N, 90.20 N, and 13.23 mm, 243.20 N, 218.88 N respectively. For both tensile and compression loading (in this case study), better elongation was noticed for the FFF-based IM pin with 50% meta-structure and hence recommended for implantation in the canine femur bone. The results are also supported by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) based surface characteristics of the fracture sites.

Synthesis of High‐Performance Polyvinylidene Fluoride Composites via Hydroxyl Anchoring Effect and Directional Freeze‐Drying Method

Polyvinylidene fluoride (PVDF) and its copolymers present extensive application prospects, especially in the field of wearable electronics. However, utilizing nanofillers for enhanced β‐phase and piezoelectric properties faces challenges like noncontinuous interfaces, poor compatibility between nanofillers and PVDF matrix, and the requirement of high‐voltage polarization, hindering extensive domain alignment on a large scale. Herein, a method is proposed to synthesize high‐performance PVDF composites by introducing hydroxylated barium titanate (H@BTO) nanoparticles and a directional freeze‐drying method to enhance β‐phase content and piezoelectric properties without polarization. Molecular dynamics simulations reveal robust binding interactions between Ba and F atoms along with OH surface terminations on H@BTO, facilitating hydrogen bonding within the PVDF matrix, resulting in dipole alignment and increased spontaneous polarization. The composite film achieves an 86.69% β phase content and a piezoelectric coefficient of ≈14.49 pm V−1 without electric polarization. The freeze‐drying PVDF‐H@BTO composite film paired with a PA6 membrane is used to fabricate triboelectric nanogenerator, demonstrating a current density of ≈107.5 mA m−2 and an output voltage of ≈832 V. Results demonstrate that the utilization of strong binding interactions between various atoms, the hydroxyl anchoring effect, and directional freeze‐drying method as a strategy holds promising prospects for synthesizing high‐performance piezoelectric composites.

Dielectric Response of Bi4Ti3O12/PVDF Composite Electrodes for Energy Storage

AbstractThis study is reporting the role of embedded ferroelectric ceramics Bi4Ti3O12 (BTO = 1–5 wt%) into the polyvinylidene fluoride (PVDF) composites on its structural, bonding, surface morphology, and dielectric response. Especially lead free flexible composite electrodes have lot of attention due to its high dielectric permittivity and energy storage density. X‐ray diffraction spectra confirms monophasic orthorhombic structure of composites, while Fourier transform infrared (FTIR) spectra confirms the bonding behavior. Scanning electron microscopy (SEM) images surface morphology of homogeneously distributed ceramic particles with interconnected network. Dielectric constant has been found to be improved from 9.56 to 13.73 for BTO5%PVDF95% composites at frequency of 1 kHz attributes promoted interfacial polarization of PVDF and effectively limited the charge leakage in the composites, implying promising applications in flexible electronic devices.

Effect of autoclaving on the dimensional stability and surface characteristics of 3D printed PVDF composite-based implants

In the past decade, a lot of work has been reported on the use of polyvinylidene fluoride (PVDF) based thermoplastic composites as energy storage devices, and implant materials. But hitherto little has been reported on the dimensional stability and surface characteristics of 3D-printed PVDF composites after autoclaving for implant applications. In this study, the effect of autoclaving on surface characteristics (Shore-D hardness, surface roughness (Ra), morphological characteristics), and dimensional stability of 3D printed PVDF-hydroxyapatite (HAp)- chitosan (CS) composite has been reported for implant applications. The signal-to-noise (S/N) ratio approach was used to ascertain the best setting of process parameters for 3D printing by fused filament fabrication (FFF) process. This study suggests that the best setting for the FFF process, for the 3D printing of PVDF composite (90%PVDF-8%HAp-2%CS) are the nozzle temperature (NT) of 225°C, raster angle (RA) 0°, and printing speed (PS) 40 mm/s, resulting in Shore-D hardness 48.5 HD (before autoclaving) and 55.0 HD (after autoclaving), dimensional deviation 0.01 mm (after autoclaving). The results are supported by scanning electron microscopy (SEM) and Fourier transmission infrared (FTIR) spectroscopy analysis.

Low-cost, simple preparation and outstanding energy density of glass fiber reinforced PVDF polymer flexible composites

To make the product commercially viable and applicable, the inclusion of glass fiber filler with a low cost and medium dielectric constant (ε) is adopted as the filler. Synchronously, representative polyvinylidene fluoride (PVDF) with high permittivity and breakdown strength is selected as optimal polymer matrix. And surface modifying agent is employed as organic coatings to weaken the surface energy of glass fiber and boost the interfacial inter-action. An investigation of dielectric properties was conducted by preparing flexible composites consisting of various content of glass fiber. The ε of composites can be significantly enhanced in the PVDF composites with glass fiber, and the breakdown strength (BDS) is remained at a high level. Moreover, within a specific content range, glass fiber makes the ε and BDS of the material increase synchronously. This work provides a facile strategy for the development of excellent performance, simple preparation and low-cost flexible composites.

Tailoring the Electrical Response of Polyvinylidene Fluoride Nanocomposites with Electrically Conductive and Dielectric Fillers

Polymer‐based composites combining the flexibility, low density, and processability of the matrix with the tailored functional performance provided by the fillers are also particularly suitable for large area, flexible, and printable applications. Herein, polyvinylidene fluoride (PVDF) composites with conductive graphene nanoplatelets (G‐NPL) and high‐dielectric constant ceramics, including barium and strontium titanate (BT and SrT), have been developed to achieve electrically conductive and high‐dielectric response materials, respectively. Flexible composites reinforced with 45 wt% ceramic content lead to a dielectric constant of ε´ = 33 and 25 for BT and SrT, respectively, 6 and 4 times higher than for pristine PVDF. Further, the inclusion of G‐NPL allows for the development of highly conductive composites with a maximum conductivity of 5.5 × 10−2 (Ω.m)−1 for a 5 wt% filler content, 10 orders of magnitude larger than PVDF. The G‐NPL and ceramic in optimized contents in PVDF tricomposites do not enhance the dielectric properties compared to PVDF‐ceramic composites. Theoretical analysis has been used to determine the critical percolation threshold of the PVDF/G‐NPL, which occurs at 0.6 wt% G‐NPL content with a critical exponent of t = 2.49 and to describe the dielectric properties of the composites, allowing to further tailor materials responses for specific application needs.

The effect of porosity on flexoelectricity in 3D printed aluminum/polyvinylidene fluoride composites

We investigated the relationship between porosity and flexoelectricity for aluminum (Al)/polyvinylidene fluoride (PVDF) composites. Neat PVDF, composites of micron aluminum (μAl)/PVDF, and composites of nano aluminum (nAl)/PVDF were 3D printed, and the flexoelectric response was measured using a cantilever beam test setup. Voids (up to 72.4 mm3) were incorporated into the samples by decreasing the infill percent of the 3D printed material. We found that increasing the porosity via millimeter scale voids incorporated into the infill pattern decreased the average effective flexoelectric coefficient relative to the near full-density (100% infill) control samples. This contrasts with other studies that have shown increasing micron scale porosity increases the flexoelectric coefficient. In addition, we measured higher flexoelectric responses for nAl/PVDF than μAl/PVDF as well as for samples printed by the Hyrel 3D SR printer as opposed to the Ender 3 V2 printer. These results indicate that charge generation due to flexoelectricity can be altered by changing parameters such as porosity, particle size of inclusions, or manufacturing method. Smaller voids and fine particles can induce larger strain gradients than larger inhomogeneities, leading to increased flexoelectric coefficients. A competing effect is that more porosity leads to less materials, which can decrease the flexoelectric coefficient.

Investigating the torsional characteristics of 3D printed polyvinylidene fluoride composite

In the recent past some studies have been reported on the compressive, tensile, and flexural properties of 3D-printed polyvinylidene fluoride (PVDF) composite-based intramedullary (IM) pins for canines. However, in actual working conditions (due to trauma or accident), the IM pin may also be under torsional loading conditions. But hitherto little has been testified on the torsional behavior of PVDF composite-based IM pins. This study highlights the torsional behavior at 1 rpm (from 0 to 800° of the angle of twist/rotation) of PVDF composite (PVDF-90%; hydroxyapatite (HAp8%); chitosan (CS2%)) based IM pin fabricated by fused filament fabrication (FFF) process. The study suggests that better torsional properties were obtained for 3D printed samples prepared at nozzle temperature (NT) of 235°C, raster angle (RA) of 45°, and printing speed (PS) of 60 mm/s respectively resulting in a maximum torque of 3.44 Nm at the angle of twist of 800° (as per ASTM A938). The morphological analysis based on scanning electron microscopy (SEM) supports the results of the fractured surface (at cross section) and along the lateral axis.

Thermal conductivity and fractal texture formation in β-Si3N4/polyvinylidene fluoride composites

Additive incorporation into polymers can enhance properties, such as the dielectric constant and thermal conductivity. The improved properties of polymer composites have largely been attributed to aggregate and network formation, but the influence of material texture requires clarification. Herein, the relationship between the texture of composite materials and thermal conductivity was investigated based on the fractal nature of composites consisting of polyvinylidene fluoride (PVDF) with β-Si3N4 (SN) as a high-thermal-conductivity filler. The SN particle groups were found to contribute to the formation of thermal conduction paths in the composite material and, thus, improve the thermal conductivity. The characteristics of the particle group clusters involved in SN particle percolation were elucidated by analyzing the interactions between multiple particles as a function of the amount of each fractal dimension. In addition, based on the statistical relationships obtained from the multifractal analysis, the strengths of the interactions between particles during thermal conduction path formation were estimated. Overall, the texture of the SN/PVDF material was characterized by local particle group formation (self-assembly) and subsequent global particle group network construction (self-organization), depending on the amount of SN added. These results suggest that multifractal dimensions can be used as material design indices for the texture of polymer composites.

Improved pyroelectric performances of functionally graded graphene nanoplatelet reinforced polyvinylidene fluoride composites: Experiment and modelling

Polyvinylidene fluoride (PVDF), as a pyroelectric polymer, has great potential applications in electronic devices and sensors. However, the low pyroelectric properties of pure PVDF limit its application. In this work, functionally graded graphene nanoplatelet (FG-GNP) reinforced PVDF composite films are prepared and test for their pyroelectric performance. Apart from experiments, the pyroelectric properties of the films are modelled and analyzed by finite element analysis (FEA), which is verified by the experiments as conducted. It demonstrates that the pyroelectric properties of FG-GNP/PVDF composite films are significantly improved compared to the homogeneous GNP/PVDF composite counterparts. It is found that for the same thickness and amount of GNP added, the increase in the number of layers leads to enhanced pyroelectric properties of the composite films. When the GNP concentration of the layer closed to the surfaces of the FG-GNP/PVDF composite film is higher, the pyroelectric properties and temperature stability of the film are more favorable.

Enhanced dielectric properties of polyvinylidene difluoride composite films by boron nitride nanosheet @ metal organic framework hybrid fillers

Generally, it is hard to simultaneously achieve the enhanced dielectric constant and breakdown strength of polymeric composite by simply introducing fillers into polymers. In this work, a novel hybrid fillers boron nitride nanosheet @ metal organic framework (BNNS@MOF), in which the nanoscale UiO-66-NH2 were epitaxially loaded on layer surface of the BNNSs, was prepared by the hydrothermal reaction. The test results indicate that the BNNS@MOF hybrid fillers were endowed with high breakdown resistance of BNNS and high dielectric constant of UiO-66-NH2. After introducing 1 wt% BNNS@MOF hybrid fillers into polyvinylidene fluoride (PVDF) at the frequency of 102 Hz, PVDF composite films demonstrated a relatively high dielectric constant (ε = 10.7), and energy density (Ue = 6.06 J/cm3) under the high breakdown strength (Eb = 378 MV/m), but low dielectric loss (tan (δ) = 0.039). Compared to PVDF with simply mixed BNNS and UiO-66-NH2 (ε = 12, tan (δ) = 0.061, Ue = 3.14 J/cm3, Eb = 249 MV/m), hybrid fillers showed significant advantages. Our work presented a new idea to construct the PVDF composites with simultaneously enhanced dielectric constant and breakdown strength by introducing hybrid fillers. The hybrid fillers showed promising application in the field of film capacitors.

On digital twinning of fused filament fabrication for tensile properties of polyvinylidene fluoride composites-based functional prototypes

In the last two decades, several studies have been conducted for the process parametric optimization of fused filament fabrication (FFF) with a variety of thermoplastic composites, especially for mechanical properties. But hitherto less has been conveyed, on the development of dynamic reduced order models (ROMs) for digital twining (DT) of tensile properties (of 3D printed implants/scaffolds) with novel thermoplastic-based composites. In this study, for the generation of dynamic ROM (for hybrid analytics), the signal-to-noise (S/N) ratio was used to ascertain the best settings of parameters for tensile properties of polyvinylidene fluoride (PVDF) composite. The study suggests that the best setting of the FFF process, for the 3D printing of PVDF composite (90% PVDF, 8% hydroxyapatite (HAp), and 2% Chitosan (CS) (for maximizing the tensile properties as per ASTM-D638-Type-V) are nozzle temperature (NT) of 235°C, raster angle (RA) 45°, printing speed (PS) of 60 mm/s respectively resulting in peak load (PL) 394.87 N, peak stress (PSt) 33.92 MPa, Young’s modulus (E) 2.606 MPa. For a modulus of toughness (MOT) of 0.484 MPa, the best settings are NT 230°C, RA 90°, and PS 50 mm/s. The results are supported by the morphological analysis.

Comparation of barium titanate and multi-walled carbon nanotubes modified PVDF composites: A perspective of dielectric, crystalline, rheological and mechanical properties

Ceramic powders and conductive particles are the two most used functional fillers for preparing dielectric polymer composites. In this work, barium titanate (BT) and multi-walled carbon nanotubes (MWCNT) were mixed in polyvinylidene fluoride (PVDF) by melt blending. The crystal structure, thermodynamic behavior, dielectric, rheological and mechanical properties of PVDF/BT and PVDF/MWCNT composites were systematically studied and compared. It was found that the volume addition of BT was about 100 times that of MWCNT when dielectric constant (ε′) of composites was the same level. For example, the ε′ of PVDF/BT and PVDF/MWCNT were 68.9 (102 Hz) and 70.4 (102 Hz) when the content of BT and MWCNT were 50 vol% and 0.5 vol%, respectively. However, with the addition of 0.5 vol% MWCNT, the dielectric loss (tanδ) of PVDF/MWCNT was significantly higher than that of PVDF/BT. Additionally, BT had a substantial impact on the crystalline and rheological properties, and worsened the mechanical performance of PVDF/BT. Conversely, MWCNT exerted minimal effects on the crystalline and rheological properties, but enhanced the impact and tensile strength of PVDF/MWCNT.