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Book ChapterDOI

Biopolymer Composites With High Dielectric Performance: Interface Engineering

TL;DR: In this article, the preparation and dielectric behavior of various biopolymer composites is presented, including metal nanoparticles and carbon-based nanofillers such as carbon nanotubes, graphene, etc.
Abstract: In recent years, there is a growing interest in studying the dielectric behavior of biopolymer composites due to their potential application as a dielectric material in various electronic devices such as microchips, transformers, and circuit boards. Conducting electroactive polymer composites have also been investigated for various potential applications which include biological, biomedical, flexible electrodes, display devices, biosensors, and cells for tissue engineering. In this chapter, the preparation and dielectric behavior of various biopolymer composites is presented. These biopolymer composites generally consist of nanoscale metal nanoparticles and carbon-based nanofillers such as carbon nanotubes, graphene, graphene oxide (GO), etc., dispersed into the polymer matrix. The physical and chemical properties of these fillers and their interactions with polymers have a significant effect on the microstructure and the final properties of nanocomposites. The biopolymer composites with excellent dielectric properties show great promise as an energy storage dielectric layer in high-performance capacitor applications such as embedded capacitors. This chapter highlights some of the examples of such biopolymer composites; their processing and dielectric behavior will be discussed in detail.
Citations
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Journal Article
TL;DR: In this article, Boron nitride nanotubes (BNNT)/polyvinyl alcohol (PVA) composite fibers were fabricated via electrospinning so that all BNNTs became aligned in the fiber casting direction.
Abstract: Boron nitride nanotube (BNNT)/polyvinyl alcohol (PVA) composite fibers (<5 vol % BNNTs) were fabricated via electrospinning so that all BNNTs became aligned in the fiber casting direction. A several-fibers-thick ensemble of parallel-arranged contacting fibers made a single polymer sheet. Numerous sheets were then stacked in different ways with respect to the BNNT orientation (all fibers in adjacent sheets were either parallel or alternately rotated 90°) to make multilayer films that were finally hot-pressed. Various BNNT textures were reflected by the corresponding differences in the measured thermal conductivities of the resultant films due to anisotropy of thermal transport in the nanotubes. The highest values (0.54 W/mK) were obtained along the long axes of aligned BNNTs. Somewhat lower values (0.38 W/mK) were documented in films with alternately stacked fibers/tubes. The theoretical thermal conductivity values were estimated using the Nielsen’s model. These show good match with the experimental data. ...

162 citations

Journal ArticleDOI
TL;DR: In this paper, the potential and market stability of gelatin has been discussed and its recent studies are summarised in this paper, focusing on assessing the general utilities of the various sources of collagen as gelatin derivatives.

120 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the recent progress in polymer electrolytes for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization, and provided an insight from lab research to commercialization, relevant challenges, device configurations, and life cycle analysis.
Abstract: Owing to the development of aqueous rechargeable zinc-ion batteries (ZIBs), flexible ZIBs are deemed as potential candidates to power wearable electronics. ZIBs with solid-state polymer electrolytes can not only maintain additional load-bearing properties, but exhibit enhanced electrochemical properties by preventing dendrite formation and inhibiting cathode dissolution. Substantial efforts have been applied to polymer electrolytes by developing solid polymer electrolytes, hydrogel polymer electrolytes, and hybrid polymer electrolytes; however, the research of polymer electrolytes for ZIBs is still immature. Herein, the recent progress in polymer electrolytes is summarized by category for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization. Aiming to provide an insight from lab research to commercialization, the relevant challenges, device configurations, and life cycle analysis are consolidated. As flexible batteries, the majority of polymer electrolytes exploited so far only emphasizes the electrochemical performance but the mechanical behavior and interactions with the electrode materials have hardly been considered. Hence, strategies of combining softness and strength and the integration with electrodes are discussed for flexible ZIBs. A ranking index, combining both electrochemical and mechanical properties, is introduced. Future research directions are also covered to guide research toward the commercialization of flexible ZIBs.

119 citations

Journal ArticleDOI
TL;DR: A systematic review methodology based on the application of this novel technology in the field of drug delivery along with the manufacturing of polypills with varied release profiles and geometries is carried out.

72 citations

References
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Journal ArticleDOI
TL;DR: In this article, the pyroelectric and dielectric properties of TGS-gelatin films were investigated and the results were explained using a model of the TGSgelatin film structure in which the gelatin phase is a superionic conductor or solid electrolyte.
Abstract: Triglycine sulfate-gelatin (TGS-gelatin) films were grown by evaporation of the water from a solution containing gelatin and TGS. The pyroelectric and dielectric properties of the films were highly dependent on their water content. Moist films had higher pyroelectric coefficients and lower coercive fields than dry films. The dielectric permittivity increased strongly with an increase of water content and had a fractional power frequency dependence. The results are explained using a model of the TGS-gelatin film structure in which the gelatin phase is a superionic conductor or solid electrolyte. Absorption of water causes the formation of electric double layers at the electrode film and TGS crystallite-gelatin phase interfaces.

16 citations

Journal ArticleDOI
TL;DR: In this paper, physical and structural properties of gelatin films were studied as a function of glycerol content, focusing on the interactions between the glycerols, film structure and the moisture content.
Abstract: Some physical and structural properties of gelatin films were studied as a function of glycerol content, focusing on the interactions between the glycerol, film structure and the moisture content. Fourier transform infrared spectroscopy was used to study the changes of the main functional groups of the film. The displacement in the amide's position occurred with lower plasticizer content, possible due to the predominance of bound water in the film matrix. The glycerol increased the flexibility of the films, as determined by the measurements of tensile strength, elongation and elastic modulus. Finally, microwave reflected signal measurements and dielectric constant measurements were also found to be sensitive to glycerol content, presumably due to its hydrophilic nature.

15 citations

Journal ArticleDOI
TL;DR: In this paper, synthetic copolymers poly(e-caprolactone-co-vinylphosphonic acid) (P(O)(OH)2) and poly(poly(eCaprolactoenc-dimethylvinyl phosphoester)(P(MDOVPE)) were used to prepare composites with polylactide (PLac) and hydroxyapatite (HAp) and were observed by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX)
Abstract: Synthetic copolymers poly(e-caprolactone-co-vinylphosphonic acid) (P(MDOVPA) and poly(e-caprolactone-co-dimethylvinylphosphoester) (P(MDOVPE)) were used to prepare composites with polylactide (PLac) and hydroxyapatite (HAp). The P(MDOVPA) is used as filler in PLac films, as it has pendant functional groups P(O)(OH)2, providing nucleation sites for the deposition of HAp in simulated body fluid. HAp growth on P(MDOVPA) powder and PLac-P(MDOVPA) film was observed by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). P(MDOVPE) and PLac blend are miscible, and the incorporation of hydrophilic P(MDOVPA) into PLac increased the hydrophilicity of the blend. Synthetic HAp was used to make multilayered, alternating organic–inorganic composites with porous PLac-P(MDOVPE) blends. ©©1999©Kluwer Academic Publishers

15 citations

Journal ArticleDOI
N. M. Shash1
12 Jun 2013-Ionics
TL;DR: In this article, the effect of vanadium pentoxide (V2O5) on the electrical, dielectric, and optical properties of polyvinyl alcohol (PVA) and V2O-5 nanocomposites was examined.
Abstract: In this study, the effect of vanadium pentoxide (V2O5) on the electrical, dielectric, and optical properties of poly(vinyl alcohol) (PVA)/V2O5 nanocomposites was examined. The PVA/V2O5 nanocomposites were prepared by solution mixing, followed by film casting. The as-prepared films were characterized by X-ray diffraction, thermogravimetric analysis, as well as impedance spectroscopy. The obtained results indicated that, with increasing V2O5 content, the PVA composite exhibits considerable vestige of crystallization and the PVA peaks become broader. The electrical conductivity, σ dc, increases as the temperature and the dopant level of V2O5 increase. The frequency dependence of alternating current conductivity was governed by a critical frequency, ω p. The values of ω p are found to be thermally activated. The loss tangent (tan δ) shows a peak with the frequency, which indicates a dielectric relaxation in these composites with relaxation time decreases with both temperature and V2O5 content increase. Optical absorption edge and direct and indirect energies for all mentioned samples were determined and discussed.

14 citations

Journal ArticleDOI
TL;DR: In this article, a composite of oil palm empty fruit bunch fiber (OPEFB), environmentally friendly polycaprolactone (PCL) and nickel oxide (NiO) was fabricated by compounding all materials in the Thermo Haake blending machine.
Abstract: The composite of oil palm empty fruit bunch fiber (OPEFB) which is the waste product of oil palm industry, environmentally friendly polycaprolactone (PCL) and nickel oxide (NiO) were fabricated by compounding all materials in the Thermo Haake blending machine. The 3.5x6.1x0.8 cm 3 samples with different percentage of OPEFB/PCL/NiO ratio were prepared for dielectric measurement and analysis. The dielectric properties of the substrates were obtained with the open ended coaxial method for microwave frequency range between 0.2 MHz and 20 GHz. The results reveal that the permittivity values of the composite can be tuned by changing the ratio of OPEFB/PCL/NiO prior to compounding and blending. These composites may offer alternatives to Teflon, which is made primarily from petroleum, for applications in radio and communications, especially in the fabrication of antennas, transmission and other microwave components.

14 citations