scholarly journals Significantly Enhanced Dielectric Properties of Ag-Deposited (In1/2Nb1/2)0.1Ti0.9O2/PVDF Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1788
Author(s):  
Wattana Tuichai ◽  
Pornsawan Kum-onsa ◽  
Supamas Danwittayakul ◽  
Jedsada Manyam ◽  
Viyada Harnchana ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Ag Nanoparticles ◽  
Vinylidene Fluoride ◽  
Interfacial Polarization ◽  
Theory Model ◽  
Hybrid Particles ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Poly Vinylidene Fluoride ◽  
Pure Pvdf

The enhanced dielectric permittivity (ε′) while retaining a low loss tangent (tanδ) in silver nanoparticle−(In1/2Nb1/2)0.1Ti0.9O2/poly(vinylidene fluoride) (Ag-INTO/PVDF) composites with different volume fractions of a filler (fAg-INTO) was investigated. The hybrid particles were fabricated by coating Ag nanoparticles onto the surface of INTO particles, as confirmed by X-ray diffraction. The ε′ of the Ag−INTO/PVDF composites could be significantly enhanced to ~86 at 1 kHz with a low tanδ of ~0.044. The enhanced ε′ value was approximately >8-fold higher than that of the pure PVDF polymer for the composite with fAg-INTO = 0.5. Furthermore, ε′ was nearly independent of frequency in the range of 102–106 Hz. Therefore, filling Ag−INTO hybrid particles into a PVDF matrix is an effective way to increase ε′ while retaining a low tanδ of polymer composites. The effective medium percolation theory model can be used to fit the experimental ε′ values with various fAg-INTO values. The greatly increased ε′ primarily originated from interfacial polarization at the conducting Ag nanoparticle–PVDF and Ag–INTO interfaces, and it was partially contributed by the high ε′ of INTO particles. A low tanδ was obtained because the formation of the conducting network in the polymer was inhibited by preventing the direct contact of Ag nanoparticles.

scholarly journals Effects of Sub-Micro Sized BaTiO3 Blocking Particles and Ag-Deposited Nano-Sized BaTiO3 Hybrid Particles on Dielectric Properties of Poly(vinylidene-fluoride) Polymer

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3641
Author(s):  
Kanyapak Silakaew ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Loss Tangent ◽  
Vinylidene Fluoride ◽  
Interfacial Polarization ◽  
Blocking Effect ◽  
Alternative Route ◽  
Hybrid Particles ◽  
High Permittivity ◽  
Poly Vinylidene Fluoride

This work provided an alternative route to balance the significantly increased dielectric permittivity (ε′) and effectively retained tanδ using an effective two-step concept. Ag-deposited nano-sized BaTiO3 (Ag-nBT) hybrid particle was used as the first filler to increase the ε′ of the poly(vinylidene-fluoride) (PVDF) polymer via the strong interfacial polarization and a high permittivity of nBT and suppress the increased loss tangent (tanδ) owing to the discrete growth of Ag nanoparticles on the surface of nBT, preventing a continuous percolating path. The ε′ and tanδ values at 103 Hz of the Ag-nBT/PVDF composite with fAg-nBT~0.29 were 61.7 and 0.036. The sub-micron-sized BaTiO3 (μBT) particle was selected as the blocking particles to doubly reduce the tanδ with simultaneously enhanced ε′ due to the presence of the tetragonal BT phase. The μBT blocking particles can effectively further inhibit the formation of conducting network and hence further reducing tanδ. By incorporation of μBT clocking particles with fμBT = 0.2, the ε′ value of the Ag-nBT/PVDF-μBT composite (fAg-nBT = 0.30) can significantly increase to 161.4, while the tanδ was reduced to 0.026. Furthermore, the tanδ was lower than 0.09 in the temperature range of −60–150 °C due to the blocking effect of μBT particles.

Simulations of High-Strain Electrostrictive Chlorinated Terpolymers

2003 ◽  
Vol 785 ◽  
Author(s):  
George J. Kavarnos ◽  
Thomas Ramotowski
Keyword(s):  
Vinylidene Fluoride ◽  
High Strain ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Annealing Conditions ◽  
Poly Vinylidene Fluoride ◽  
Electromechanical Responses ◽  
Kinetics Of

ABSTRACTChlorinated poly(vinylidene fluoride/trifluoroethylene) terpolymers are remarkable examples of high strain electrostrictive materials. These polymers are synthesized by copolymerizing vinylidene fluoride and trifluoroethylene with small levels of a third chlorinated monomer. The electromechanical responses of these materials are believed to originate from the chlorine atom, which, by its presence in the polymer chains and by virtue of its large van der Waals radius, destroys the long-range crystalline polar macro-domains and transforms the polymer from a normal to a high-strain relaxor ferroelectric. To exploit the strain properties of the terpolymer, it is desirable to understand the structural implications resulting from the presence of the chlorinated monomer. To this end, computations have been performed on model superlattices of terpolymers using quantum-mechanical based force fields. The focus has been on determining the energetics and kinetics of crystallization of the various polymorphs that have been identified by x-ray diffraction and fourier transform infrared spectroscopy. The chlorinated monomer is shown to act as a defect that can be incorporated into the lamellar structures of annealed terpolymer without a high cost in energy. The degree of incorporation of the chlorinated monomer into the crystal lattice is controlled by annealing conditions and ultimately determines the ferroelectric behavior of the terpolymers.

scholarly journals Fabrication of Piezoelectric PVDF/PAR Composites Using a Sheath-Core Fiber Method

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2214
Author(s):  
Min Hong Jeon ◽  
Yu Rim Lee ◽  
Hyeon Soo Lim ◽  
Jong Sung Won ◽  
Seung Goo Lee
Keyword(s):  
Vinylidene Fluoride ◽  
Piezoelectric Properties ◽  
Testing Machine ◽  
X Ray Diffraction ◽  
Composite Surface ◽  
Fiber Assembly ◽  
Universal Testing ◽  
Poly Vinylidene Fluoride ◽  
Core Fiber ◽  
Growing Conditions

We report the preparation of sheath-core type fibers made from poly(vinylidene fluoride) (PVDF) and polyarylate (PAR) using melt conjugate spinning to fabricate piezolectric composites. The morphology of this sheath-core fiber was determined through scanning electron microscopy. Subsequently, by the compression molding of the PVDF/PAR sheath-core fiber assembly, we fabricated PVDF/PAR composites exhibiting piezoelectric properties. For enhancing the piezoelectric properties, we increased the concentration of PVDF β-crystalline phase in the PVDF/PAR composite through poling post-treatments. The resulting crystal structure of PVDF was confirmed through infrared spectroscopy and X-ray diffraction. A universal testing machine was employed to measure the tensile properties of the PVDF/PAR composites. Finally, through a hydrothermal growing method, ZnO was coated on the composite surface to enhance the piezoelectric properties, which were subsequently optimized by varying the hydrothermal growing conditions.

Structures and Physical Properties of Multi-Walled Carbon Nanotube-Filled PVDF Thermoplastic Composites

2007 ◽  
Vol 124-126 ◽  
pp. 1117-1120 ◽  
Author(s):  
Dong Wook Chae ◽  
Young Wan Nam ◽  
Seung Sangh Wang ◽  
S.M. Hong
Keyword(s):  
Carbon Nanotube ◽  
Vinylidene Fluoride ◽  
Thermoplastic Composites ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Loading Level ◽  
Multi Walled Carbon Nanotube ◽  
Poly Vinylidene Fluoride ◽  
Internal Mixer

Poly(vinylidene fluoride) (PVDF) / multi-walled carbon nanotube (MWNT) thermoplastic composites was melt compounded in an internal mixer. The percolation level for this system in electrical conductivity clearly occured between 2 and 2.5 wt%. PVDF/MWNT thermoplastic composites exhibited an increased crystallization temperature with the loading level, at 10 wt% loading by ca. 6. In addition, they presented a shoulder posterior to the main melting peak and an increased endpoint of the peak. In the Wide Angle X-ray Diffraction (WAXD) patterns, the incorporation of MWNT produced a larger shoulder at 2θ =20.7° with increasing the loading level, corresponding to the β-form crystal of PVDF.

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