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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: The compact composites obtained have been found to be mechanically flexible, and this flexibility has been improved further by heating at 120 degrees C for 20 min in an autoclave with saturated steam pressure.
Abstract: Chitosan/hydroxyapatite (HAp) composites with a homogeneous nanostructure have been prepared by a co-precipitation method. According to TEM observations, HAp crystallites in the composites formed elliptic aggregations 230 nm in length and 50 nm in width. The typical length of the aggregations corresponded approximately to that of a chitosan molecule. The size of the constituent HAp crystallites was found to be predominantly 30 nm in length and 10 nm in width, and the c-axes were well aligned in parallel with the chitosan molecules in the respective aggregations. The growth of the HAp crystallites is considered to occur at nucleation sites, most probably forming the complexes with amino groups on chitosan with calcium ions. The compact composites obtained have been found to be mechanically flexible, and this flexibility has been improved further by heating at 120 degrees C for 20 min in an autoclave with saturated steam pressure.

400 citations

Journal ArticleDOI
TL;DR: Boron nitride nanosheets were dispersed in polymers to give composite films with excellent thermal transport performances approaching the record values found in polymer/graphene nanocomposites.
Abstract: Boron nitride nanosheets were dispersed in polymers to give composite films with excellent thermal transport performances approaching the record values found in polymer/graphene nanocomposites. Similarly high performance at lower BN loadings was achieved by aligning the nanosheets in poly(vinyl alcohol) matrix by simple mechanical stretching (see picture).

384 citations

Journal ArticleDOI
TL;DR: A novel method for the fabrication of soft, low impedance, high charge density, and controlled releasing nanobiomaterials that can be used for the surface modification of neural microelectrodes to stabilize the electrode/tissue interface is reported.
Abstract: Neural electrodes are designed to interface with the nervous system and provide control signals for neural prostheses. However, robust and reliable chronic recording and stimulation remains a challenge for neural electrodes. Here, a novel method for the fabrication of soft, low impedance, high charge density, and controlled releasing nanobiomaterials that can be used for the surface modification of neural microelectrodes to stabilize the electrode/ tissue interface is reported. The fabrication process includes electrospinning of anti-inflammatory drug-incorporated biodegradable nanofibers, encapsulation of these nanofibers by an alginate hydrogel layer, followed by electrochemical polymerization of conducting polymers around the electrospun drug-loaded nanofibers to form nanotubes and within the alginate hydrogel scaffold to form cloud-like nanostructures. The threedimensional conducting polymer nanostructures significantly decrease the electrode impedance and increase the charge capacity density. Dexamethasone release profiles show that the alginate hydrogel coating slows down the release of the drug, significantly reducing the burst effect. These multifunctional materials are expected to be of interest for a variety of electrode/tissue interfaces in biomedical devices.

380 citations

Journal ArticleDOI
TL;DR: In this article, the gallery spacing of organoclay and polylactide (PLA) nanocomposites was investigated in different types of clays, smectite, montmorillonite (MMT), and mica, to prepare their corresponding organoclays.
Abstract: In the preparation of polymer/clay nanocomposites, organoclay plays an important role in lipophilizing and dispersing the clay into less polar polymer matrixes. Organic modifiers of various chain lengths were examined in different types of clays, smectite, montmorillonite (MMT), and mica, to prepare their corresponding organoclays. The layered structure and gallery spacing of organoclays and polylactide (PLA) nanocomposites shows that, with a modifier of the same chain length, the gallery spacing of the organoclay was largest for mica and smallest for smectite because of the higher ion-exchange capacity of mica and physical jamming of the modifier due to a restricted conformation at the core part of the clay of larger size. The increment of the modulus in a smectite nanocomposite, compared to that of PLA, is higher than MMT or mica nanocomposite due to better dispersion in a smectite system for the same clay loading. Being a well-dispersed system, smectite nanocomposites have better gas barrier properties...

379 citations

Journal ArticleDOI
TL;DR: PP/HA composite biomaterials are promising candidates for tissue engineering and wound-healing applications that may benefit from both electrical stimulation and enhanced vascularization.
Abstract: New tissue engineering technologies will rely on biomaterials that physically support tissue growth and stimulate specific cell functions. The goal of this study was to create a biomaterial that combines inherent biological properties which can specifically trigger desired cellular responses (e.g., angiogenesis) with electrical properties which have been shown to improve the regeneration of several tissues including bone and nerve. To this end, composites of the biologically active polysaccharide hyaluronic acid (HA) and the electrically conducting polymer polypyrrole (PP) were synthesized and characterized. Electrical conductivity of the composite biomaterial (PP/HA) was measured by a four-point probe technique, scanning electron microscopy was used to characterize surface topography, X-ray photoelectron spectroscopy and reflectance infrared spectroscopy were used to evaluate surface and bulk chemistry, and an assay with biotinylated hyaluronic acid binding protein was used to determine surface HA content. PP/HA materials were also evaluated for in vitro cell compatibility and tissue response in rats. Smooth, conductive, HA-containing PP films were produced; these films retained HA on their surfaces for several days in vitro and promoted vascularization in vivo. PP/HA composite biomaterials are promising candidates for tissue engineering and wound-healing applications that may benefit from both electrical stimulation and enhanced vascularization.

378 citations