scholarly journals Polarization Properties and Polarization Depth Profiles of (Cd:Zn)S/P(VDF-TrFE) Composite Films in Dependence of Optical Excitation

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1205
Author(s):  
Sebastian Engel ◽  
David Smykalla ◽  
Bernd Ploss ◽  
Stephan Gräf ◽  
Frank Müller
Keyword(s):  
Depth Profile ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
Optical Excitation ◽  
Pyroelectric Coefficient ◽  
Excitation Intensity ◽  
Peak Voltage ◽  
Small Peak ◽  
Temporal Decay ◽  
Poly Vinylidene Fluoride

The influence of optical excitation intensity on the electrical, ferroelectric and pyroelectric properties of ferroelectric-semiconductor-composites was investigated. For this purpose, composite thin films consisting of poly(vinylidene fluoride-co-trifluoroethylene) and 10 vol % (Cd:Zn)S particles with a thickness of 34 µm were fabricated. The samples were used to measure the absolute pyrocoefficient and to determine the relative pyroelectric depth profile using Laser Intensity Modulated Method. It was shown that a polarization of the samples without an optical excitation at the utilized relatively small peak-to-peak voltages could not be verified by the Sawyer–Tower circuit and the measurement setup of the pyroelectric coefficient, respectively. Both remanent polarization and pyroelectric coefficients increased with increasing optical excitation intensity during poling as well as increasing peak-to-peak voltage. The pyrocoefficient shows a temporal decay in the first hours after poling. The specific heat and thermal conductivity or the thermal diffusivity are required for the calibration of the pyroelectric depth profile. Rule of mixture and photo-acoustic investigations proved that the thermal properties of the utilized composites do not differ significantly from those of the pristine polymer. Based on the pyroelectric depth profile which is proportional to the polarization profile, the existing “three phase model” has been extended to generate a replacement circuit diagram, explaining the local polarization due to the optical excitation dependency for both local resistivity and local field strength.

The structural spectra of high dilutions and their unconventional application

2021 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Saurav Arora
Keyword(s):  
Raman Spectroscopy ◽  
Electrical Properties ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
Water Structure ◽  
Laser Raman Spectroscopy ◽  
Oh Groups ◽  
Laser Raman ◽  
Poly Vinylidene Fluoride ◽  
High Dilutions

Until few years, the so-called implausible science, homeopathy, was on the verge of being rejected on conventional physicochemical grounds. The mere selection of ultrahigh dilutions (UHD) (homeopathic potencies) for experimentation by mainstream scientists seemed impossible, but the curiosity to explore the science behind homeopathy kept igniting intellectual alma mater who subjected homeopathy to laboratories and test tubes, to know beyond its clinical application. Still, there exist a huge gap and a challenge to convince a conventional scientist to go beyond his domains and look for something which is apparently invisible (beyond Avogadro). But gradually we are overcoming this dogma and exploring the finer aspects and applications of UHDs. Much research has been undertaken, at least, to protect the identity of UHDs, and we are now verge of proving the plausibility of homeopathy from every aspect. This issue of International Journal of High Dilution Research features two interesting articles on nature of UHDs and their unconventional application. The first article by NC Sukul et al aimed to decipher the nature of the water structure of UHDs of two commonly used homeopathic drugs Natrum muriaticum and Sulphur by Laser Raman Spectroscopy. This work is in the series undertaken by the group, who earlier experimented using Nuclear Magnetic Resonance; Electronic, Vibrational and Raman spectroscopy to shown differences in UHDs of various drugs. The present experiment could differentiate the intensities (potencies) of Nat-m and Sulph when compared to their controls, on the basis of hydrogen bond strength and free OH groups. The second article by Nandy et al proposes a new dimension to the application of UHD. In an interesting manner, the author used UHDs of Ferrum metallicum and Zincum oxidatum to improve the electrical properties of the electroactive Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP). The PVDF-HFP composite films were synthesized in their usual way, but an incorporation of Ferrum and Zinc-o could make the film as homeo-PVDF-composite. This enhancement of the electrical properties and are possibly due to the presence of nanoparticle, as hypothesized by the group. The nature and application of UHDs are promising but challenging areas, which can only be validated through extensive research and validation. The realm of UHDs is expanding, and the day is not far when plausibility of homeopathy would be proved from every aspect, but at the same time we should also keep the momentum of research at pace in clinical research too!

The high energy density and efficiency of PVDF-based composites with double-shell Nd-BaTiO3 particles as fillers

2020 ◽  
Vol 13 (06) ◽  
pp. 2051042
Author(s):  
Zhong Yang ◽  
Jing Wang ◽  
Long He ◽  
Chaoyong Deng ◽  
Kongjun Zhu
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
High Energy ◽  
Maximum Energy ◽  
Dielectric Constants ◽  
High Energy Density ◽  
Element Simulation ◽  
Poly Vinylidene Fluoride

Flexible dielectric capacitors are becoming shining stars in modern electronic devices. Ceramic particles with large dielectric constants and benign compatibility are attractive candidates to enhance the energy storage density of pristine polymer capacitors while guaranteeing their flexibility. In this work, double-shell structure of Al2O3 (AO) and dopamine (PDA) were successively coated on the Nd-doped BaTiO3 (NBT) particles and then introduced into the Poly(vinylidene fluoride) (PVDF) matrix. Obvious enhancement in dielectric constants was observed while the dielectric loss remained nearly constant. For the composite films with 1–4[Formula: see text]vol.% NBT@AO@PDA NPs, the maximum energy density of 9.1[Formula: see text]J/cm3 and energy efficiency of 65% was achieved at 430[Formula: see text]MV/m in the sample with 1[Formula: see text]vol.% filling ratio, which are 1.4 and 1.3 times larger than those of pristine PVDF at 450[Formula: see text]MV/m. The finite element simulation reveals the effective relief of the electric field concentration in the composite film induced by the AO and PDA layers. The greater improvement in the energy storage performance could be anticipated if the dispersity of NBT@AO@PDA NPs was further improved.

Large d33 and enhanced ferroelectric/dielectric properties of poly(vinylidene fluoride)-based composites filled with Pb(Zr0.52Ti0.48)O3 nanofibers

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 51302-51307 ◽  
Author(s):  
Jie Chang ◽  
Yang Shen ◽  
Xiangcheng Chu ◽  
Xuehui Zhang ◽  
Yu Song ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
Poly Vinylidene Fluoride

Pb(Zr0.52Ti0.48)O3 (PZT) nanofibers with diameters of 150–200 nm are prepared via electrospinning and used as dielectric fillers in poly(vinylidene fluoride) (PVDF)-based composite films.

Preparation and Dye Removal Properties of Hyperbranched Polymeric Ionic Liquid/Poly(Vinylidene Fluoride) Composite Films

2017 ◽  
Vol 890 ◽  
pp. 192-195
Author(s):  
Wen Qi Song ◽  
Yu Yang Liu ◽  
Yu Hou ◽  
Yan Wang
Keyword(s):  
Ionic Liquid ◽  
Vinylidene Fluoride ◽  
Dynamic Condition ◽  
Adsorption Property ◽  
Composite Films ◽  
Bromophenol Blue ◽  
Inversion Method ◽  
Pvdf Film ◽  
Polymeric Ionic Liquid ◽  
Poly Vinylidene Fluoride

Based on the selective adsorption property of the imidazolium-type hyperbranched polymeric ionic liquid (hb-PIm+PF6-) towards anionic dyes, it was incorporated into poly(vinylidene fluoride) (PVDF) matrix to modify PVDF film. The composite hb-PIm+PF6-/PVDF films were prepared via non-solvent-induced phase inversion method. The obtained composite films were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle goniometry. Using bromophenol blue (BPB, an acidic dye) as the model molecule, the dynamic and static adsorption properties of the hb-PIm+PF6-/PVDF films were investigated, respectively. It is significant that the hb-PIm+PF6-/PVDF composite films could efficiently remove BPB from water under dynamic condition.

scholarly journals Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1091 ◽  
Author(s):  
Eftihia Barnes ◽  
Jennifer A. Jefcoat ◽  
Erik M. Alberts ◽  
Mason A. McKechnie ◽  
Hannah R. Peel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Weight Ratio ◽  
Tensile Modulus ◽  
Physical And Mechanical Properties ◽  
Free Standing ◽  
Composite Surface ◽  
Poly Vinylidene Fluoride

Cellulose nanofibrils (CNFs) are high aspect ratio, natural nanomaterials with high mechanical strength-to-weight ratio and promising reinforcing dopants in polymer nanocomposites. In this study, we used CNFs and oxidized CNFs (TOCNFs), prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process, as reinforcing agents in poly(vinylidene fluoride) (PVDF). Using high-shear mixing and doctor blade casting, we prepared free-standing composite films loaded with up to 5 wt % cellulose nanofibrils. For our processing conditions, all CNF/PVDF and TOCNF/PVDF films remain in the same crystalline phase as neat PVDF. In the as-prepared composites, the addition of CNFs on average increases crystallinity, whereas TOCNFs reduces it. Further, addition of CNFs and TOCNFs influences properties such as surface wettability, as well as thermal and mechanical behaviors of the composites. When compared to neat PVDF, the thermal stability of the composites is reduced. With regards to bulk mechanical properties, addition of CNFs or TOCNFs, generally reduces the tensile properties of the composites. However, a small increase (~18%) in the tensile modulus was observed for the 1 wt % TOCNF/PVDF composite. Surface mechanical properties, obtained from nanoindentation, show that the composites have enhanced performance. For the 5 wt % CNF/PVDF composite, the reduced modulus and hardness increased by ~52% and ~22%, whereas for the 3 wt % TOCNF/PVDF sample, the increase was ~23% and ~25% respectively.

Dielectric Properties of Poly(vinylidene fluoride)/PMN-PT Composite Films for Embedded Capacitors

2015 ◽  
Vol 7 (9) ◽  
pp. 776-781 ◽  
Author(s):  
A. K. Batra ◽  
Almuatasim Alomari ◽  
Mary McDaniel ◽  
Kyana McKay ◽  
Marylyn Creer
Keyword(s):  
Dielectric Properties ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
Embedded Capacitors ◽  
Poly Vinylidene Fluoride
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