Effect of g-PVDF on enhanced thermal conductivity and dielectric property of Fe-rGO incorporated PVDF based flexible nanocomposite film for efficient thermal management and energy storage applications (original) (raw)
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Nanoscale, 2015
In this work, we report the superior piezoelectric energy harvester ability of a non-electrically poled Fe-doped reduced graphene oxide (Fe-RGO)/poly(vinylidene fluoride) (PVDF) nanocomposite film prepared through a simple solution casting technique that favors the nucleation and stabilization of ≈99% relative proportion of polar γ-phase. The piezoelectric energy harvester was made with non-electrically poled Fe-RGO/PVDF nanocomposite film that gives an open circuit output voltage and short circuit current up to 5.1 V and 0.254 μA by repetitive human finger imparting. The improvement of the output performance is influenced by the generation of the electroactive polar γ-phase in the PVDF, due to the electrostatic interactions among the –CH 2 –/–CF 2 – dipoles of PVDF and the delocalized π-electrons and remaining oxygen functionalities of Fe-doped RGO via ion-dipole and/or hydrogen bonding interactions. Fourier transform infrared spectroscopy (FT-IR) confirmed the nucleation of the polar γ-phase of PVDF by electrostatic interactions and Raman spectroscopy also supported the molecular interactions between the dipoles of PVDF and the Fe-doped RGO nanosheets. In addition, the nanocomposite shows a higher electrical energy density of ≈0.84 J cm −3 at an electric field of 537 kV cm −1 , which indicates that it is appropriate for energy storage capabilities. Moreover, the surface of the prepared nanocomposite film is electrically conducting and shows an electrical conductivity of ≈3.30 × 10 −3 S cm −1 at 2 wt% loading of Fe-RGO.
Preparation, Characterization, Thermal and Electrical Conductivity Properties of PVDF Composites
Using PVDF and ZrO2, polymer composites were prepared by sol gel method. Various measurements such as X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Differential Scanning Calorimetry (DSC) were used to characterize the composites. Thermal and electrical properties of the composite samples were studied. The conductivity of composites was found to increase with increase in temperature as well as with zirconia content. As temperature increases, the polymer chain acquires faster internal modes in which bond rotations produce segmental motion.
ICONIC RESEARCH AND ENGINEERING JOURNALS, 2024
Exploring the synthesis of an n-type flexible hybrid organic/inorganic composite sheet, this study enhances PVDF with Ni and Cu nanoparticles (NP) to improve its electrical conductivity and thermoelectric properties for various room temperature applications. Ni and Cu NP, synthesized through a chemical reduction method, were smoothly incorporated into a PVDF matrix. The optimal NP to PVDF ratio was determined to be 2:3 (wt), as further addition of particles led to the formation of cracks and weakened the flexibility of the sheet. The synthesized materials' elemental composition, including Ni and Ni-Cu composites in various ratios, was analyzed using XRF, aligning closely with expected ratios and highlighting synthesis precision. FTIR spectroscopy specifies molecular structures and phases in PVDF- based nanocomposites. XRD patterns confirmed Ni and Cu NP presence and revealed trends in PVDF behavior with decreasing particle size. SEM imaging depicted well-defined particles and surface coverage in PVDF/Ni sheets, with additional Cu resulting in reduced particle density on the polymer surface, indicating compositional correlation The highest power factor, 4.964 µW m-1 K -2 and figure of merit, 0.003, were achieved at 298 K for the composite with the weight ratio of PVDF/Ni (2:3). The four-probe method demonstrated an impressive conductivity of 25.64 S cm-1 at 298 K. Furthermore, Seebeck coefficient showed a - 44 µV K-1 indicating n-type behavior, and thermal conductivity was 0.5 W m-1 K - 1 , which is consistent with the low thermal conductance required for effective thermoelectric materials. Excessive addition of Cu nanoparticles to the PVDF/Ni composite disrupts optimal Ni-PVDF interaction, impeding continuous conductive pathways and diminishing electrical conductivity and thermoelectric properties, highlighting the need for precise composite formulation. Tensile strength and elastic modulus measurements were conducted, highlighting the flexibility of the developed thermoelectric material. This study lays the foundation for the successful creation of a low-cost, n-type flexible thermoelectric material using Ni nanoparticles and PVDF. Indexed Terms- PVDF, Ni nanoparticles, Flexible, n-type, Thermoelectric, Power factor
Nanomaterials
Nanocomposites of polyvinylidene fluoride (PVDF) with dimensional (1D) cobalt oxide (Co3O4) and f-MWCNTs were prepared successfully by the solution casting method. The impact of 1D Co3O4 filler and 1D Co3O4/f-MWCNTs co-fillers on the structural, thermal, and electrical behavior of PVDF were studied. The crystal structural properties of pure PVDF and its nanocomposite films were studied by XRD, which revealed a significant enhancement of β-phase PVDF in the resulting nanocomposite films. The increase in β-phase was further revealed by the FTIR spectroscopic analysis of the samples. TG, DTA, and DSC analyses confirmed an increase in thermal stability of PVDF with the addition of nano-fillers as well as their increasing wt.%. From impedance spectroscopic studies, it was found that the DC conductivity of PVDF increases insignificantly initially (up to 0.1 wt.% of nano-fillers addition), but a significant improvement in DC conductivity was found at higher concentrations of the nano-fille...