Polymer-ceramic Nanocomposites Research Articles

Tailored multilayered films of the PVDF/Ba0.8Sr0.2TiO3 nanocomposites with surface-modified nanoparticles for superior dielectric and energy storage performance

The multilayer thick film (∼40 μm) of polyvinylidene fluoride-Ba0.8Sr0.2TiO3 (PVDF-BST) have been synthesized by a tape-casting technique. The incorporated BST nanoparticles in the PVDF matrix are functionalized by −PO4−3and −OH−group, which are abbreviated as PBST-P and PBST-H multilayer films. The nature of the functional group attached with the BST nanoparticles is found to strongly influence the dielectric properties, breakdown strength and energy storage behavior of the multilayer films. The dielectric constant (at 1 kHz) of PBST-P multilayer film shows a significant increase (∼30) as compared to PBST-H film (∼22), whereas the tangent loss remains the same. The breakdown strength of PBST-P multilayer film is also high (∼381 MV/m) as compared to the PBST-H film (∼318 MV/m). PBST-P film also possesses high discharge energy density (∼7.97 J/cc at 1800 kV) and ultrahigh energy efficiency (∼98 %). Enhanced dielectric and energy storage properties of PBST-P film is attributed to the strong bridging interaction between the PVDF matrix and BST-P nanofiller, which creates additional dipoles and a strong local electric field at the interfaces. The study may lead towards the novel ways of developing polymer-ceramic nanocomposites for high-energy density capacitors, where the incorporation of functionalized nanoparticles in the polymer matrix is accompanied by the architectured structure.

Effect of interfacial layers on the temperature-dependent dielectric and impedance behavior of flexible PVDF-BST nanocomposite thick films

High energy storage performance of polymer-ceramic nanocomposites at elevated temperatures (room temperature to 100 °C) becomes unstable because of thermally unstable dielectric behavior (permittivity and loss tangent). Therefore, the present work describes the experimental and analytical investigation of the temperature-dependent dielectric behavior, AC conductivity, and impedance of flexible poly(vinylidene difluoride) (PVDF)-Ba0.8Sr0.2TiO3 (BST) nanocomposite thick films. An increase in the dielectric constant and a decrease in the loss tangent is found with an increase in the loading of BST nanoparticles in the nanocomposite thick films. The highest dielectric constant, approximately 25, and the lowest loss tangent, approximately 0.03, are observed for 10 wt% BST–loaded PVDF-BST nanocomposite at 1 kHz; the dielectric constant and the loss tangent increase to approximately 93 and approximately 1.64, respectively, at 150 °C. The dielectric constant and the loss tangent of all the PVDF-BST nanocomposites are thermally stable up to 70 °C, and then increase with further increase of the temperature. A phenomenological model is proposed to explain the experimentally observed behavior, which might be attributed to the thermally induced translational motion in the polymeric chains of PVDF, the motion of ions, and the migration of space charge in the interfacial layer of the PVDF matrix and BST nanoparticles.

Incorporation of carbon black into a sonogel matrix: improving antifouling properties of a conducting polymer ceramic nanocomposite

A new electrochemical sensor device has been developed through the modification of a polyaniline-silicon oxide network with carbon black (CB). Enhanced electrical conductivity and antifouling properties have been achieved due to the integration of this cheap nanomaterial into the bulk of the sensor. The structure of the developed material was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy techniques. Cyclic voltammetry was used to characterize electrochemically the Sonogel-Carbon/Carbon Black-PANI (SNG-C/CB-PANI) sensor device. In addition, differential pulse voltammetry was employed to evaluate the analytical response of the sensor towards sundry chlorophenols, common environmental hazards in aqueous ecosystems. The modified sensor material showed excellent antifouling properties, which led to a better electroanalytical performance than the one displayed with the bare sensor. Notably, a sensitivity of 5.48 × 103 μA mM−1 cm−2 and a limit of detection of 0.83 μM were obtained in the determination of 4-chloro-3-methylphenol (PCMC) at a working potential of 0.78 V (vs. 3 M Ag/AgCl/KCl), along with proficient values of reproducibility and repeatability (relative standard deviation < 3%). Finally, the analysis of PCMC was carried out in multiple validated water samples using the synthesized SNG-C/CB-PANI sensor device, obtaining excellent results of recovery values (97–104%). The synergetic effect of polyaniline and carbon black leads to novel antifouling and electrocatalytic effects that improve the applicability of this sensor in sample analysis versus complex conventional devices.Graphical abstract

Enhanced dielectric performance with high-temperature stability by interface-modulation of the core–shell structured imide-polymer@BT nanohybrids in PEI-based nanocomposites

Imide-polymer@BT-PEI nanohybrids exhibit superior dielectric performance and possess excellent dielectric stability from 20 to 150 °C.

Dielectric and energy storage properties of surface-modified BaTi0.89Sn0.11O3@polydopamine nanoparticles embedded in a PVDF-HFP matrix.

In the most recent electronic and electric sectors, ceramic-polymer nanocomposites with high dielectric permittivity and energy density are gaining popularity. However, the main obstacle to improving the energy density in flexible nanocomposites, besides the size and morphology of the ceramic filler, is the low interfacial compatibility between the ceramic and the polymer. This paper presents an alternative solution to improve the dielectric permittivity and energy storage properties for electronic applications. Here, the poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix is filled with surface-modified BaTi0.89Sn0.11O3/polydopamine nanoparticles (BTS11) nanoparticles, which is known for exhibiting multiphase transitions and reaching a maximum dielectric permittivity at room temperature. BTS11 nanoparticles were synthesized by a sol-gel/hydrothermal method at 180 °C and then functionalized by polydopamine (PDA). As a result, the nanocomposites exhibit dielectric permittivity (εr) of 46 and a low loss tangent (tan δ) of 0.017 at 1 kHz at a relatively low weight fraction of 20 wt% of BTS11@PDA. This is approximately 5 times higher than the pure PVDF-HFP polymer and advantageous for energy storage density in nanocomposites. The recovered energy storage for our composites reaches 134 mJ cm-3 at an electric field of 450 kV cm-1 with a high efficiency of 73%. Incorporating PDA-modified BTS11 particles into the PVDF-HFP matrix demonstrates highly piezo-active regions associated with BTS11 particles, significantly enhancing functional properties in the polymer nanocomposites.

Crystallization behaviors and related dielectric properties of semicrystalline matrix in polymer-ceramic nanocomposites

Crystallization behaviors and related dielectric properties of semicrystalline matrix in polymer-ceramic nanocomposites have been systemically investigated by using P(VDF-TrFE) 70/30 mol.% as matrix and Ba0.5Sr0.5TiO3 nanoparticles as filler. It is found that due to the presence of ceramic nanofiller, there are two types of crystals formed in the matrix: one formed on the surface of the ceramic nanoparticles and the other formed in the polymer. The former favors the all-trans β phase due to the interaction between matrix chains and ceramic surface. The later has defects that result in two low-temperature phases: the well-ordered β phase and less-ordered β phase (i.e. β′ phase). The conformation defects of the β′ phase result in it a lower dielectric permittivity than β phase. The proportion of β’ phase decreases with increasing ceramic content and only β phase can be observed in the nanocomposites with a ceramic content higher than 35 vol%. These results were reflected in and confirmed by the DSC analyses and the dielectric properties.

Breakdown strength and energy density enhancement in polymer-ceramic nanocomposites: Role of particle size distribution

Polymer-ceramic nanocomposites play a very promising role for energy-storage in high power electronics and advanced pulsed power systems, due to their extremely fast charge-discharge capability. The low energy density is the key factor hindering their application, for which large endeavors have been made in the modulation of the fraction, morphology, size, and dispersion of the particle fillers but small in that of the size distribution, which is critical for energy-storage performance. We first investigated the role of this based on simulated nanocomposites with controlled lognormal distributions via a generation algorithm devised in this work. Dielectric response, breakdown behavior and energy-storage performance were explored for distributions with different standard deviations (SD) and mean values (MV), which were solved with the energy equivalence basis and a phase-field dielectric breakdown model. With the decrease of SD and MV, the effective permittivity declines slightly with enhanced permittivity change, which was related with the enhanced local electric field with intensified fluctuation and should be originated from the major contribution of the polymer matrix from the local energy perspective; whereas improved nominal breakdown strength was achieved owing to the weakened local maximum electric field, which leads to distinctly increased nominal energy density despite the slight decline of the permittivity. Keeping the fillers within a narrow disperse outperforms employing super fine particles. This work demonstrates that enhancement in breakdown strength and energy density can be attained via particle size distribution modulation, paving a new way for the further improvement of the energy-storage performance of polymer-ceramic nanocomposites.

Enhanced Electroactive Phases in Bi3·3La0·7Ti3O12-poly (vinylidene fluoride) composites with Improved Dielectric Properties

Lead-free ceramic-polymer nanocomposites comprising poly (vinylidene fluoride) (PVDF) and homogeneously dispersed Bi3·3La0·7Ti3O12 (BLT) ceramic particles were synthesized using the solution casting method. The effect of BLT addition on the growth rate of different crystalline phases of PVDF was systematically investigated. X-ray diffraction analysis showed the presence of β-phase in all the composite samples. FTIR and Raman spectroscopy analysis also confirmed the enhancement in the electroactive β and γ phases with BLT addition. The fraction of β-phase i.e., F(β)% has been found to be 64.5% at 10 wt % BLT loading. The homogeneous distribution of ceramic particles in PVDF matrix was confirmed using field emission scanning electron microscopic analysis. The dielectric constant of the nanocomposites with 10 wt % of BLT loading can reach up to 53.5 at 100 Hz, which is attributed to the enhanced interfacial polarization and relative enhancement of electroactive phases of PVDF. The temperature-dependent dielectric measurement shows an enhancement in the dielectric constant with increasing temperature. The nanocomposites also exhibit excellent ferroelectric properties with enhancement in remanent polarization. This work suggests the possibility of enhancing the electroactive phases of PVDF with superior dielectric and ferroelectric properties. These lead-free nanocomposites may prove to have a tremendous potential in flexible sensors, data storage, and energy harvesting applications.

Sandwich-structured polymer nanocomposites with Ba0·6Sr0·4TiO3 nanofibers networks as mediate layer inducing enhanced energy storage density

Flexible ceramic-polymer nanocomposites have shown tremendous potential in energy storage applications in the electronic and electrical field. Adding high aspect radio nanofibers into the polymers could improve the energy storage properties significantly. However, using the traditional dispersing-blending-casting method is difficult to ensure the interconnection of fibers in the film plane and to avoid the percolation out-of-plane, which results in the early breakdown and limits the energy storage density. In this work, a novel processing method was designed and a unique sandwich film based on completely interconnected Ba0·6Sr0·4TiO3 nanofibers network (BST nfs) and poly-(vinylidene fluoride-co-hexafluoropropylene) was prepared. Compared to the blending films with random BST nanofibers and polymers (random P(VDF-HFP)-BST nfs), the sandwich films P(VDF-HFP)-BST nfs-P(VDF-HFP) (4 vol%) possess higher breakdown strength (2954 kV/cm) and enhanced energy storage density (9.46 J/cm3). This strategy has explored an effective way to solve the contradiction between dielectric constant and breakdown strength and to improve the energy storage density in these composited films.

Solid Electrolytes for High‐Temperature Stable Batteries and Supercapacitors

AbstractReports of recent fire accidents in the electronics and electric vehicles (EVs) industries show that thermal runaway (TR) reactions are a key consideration for the industry. Utilization of solid electrolytes (SEs) could be an important solution in to the TR issues connected to exothermic electrochemical reactions. Data on the thermal stability of modern SEs, ionic transport mechanisms, kinetics, thermal models, recent advances, challenges, and future prospects are presented in this review. Ceramic polymer nanocomposites are the most appropriate SEs for high‐temperature stable batteries (in the range of 80–200 °C). Hydrogels and ionogels can be employed as stable, flexible, and mechanically durable SEs for antifreeze (up to –50 °C) and high‐temperature (up to 200 °C) applications in supercapacitors. Besides the thermal safety features, SEs can also prolong the lifecycle of energy storage devices in next‐generation EVs, space devices, aviation gadgets, defense tools, and mobile electronics.

The effects on antioxidant enzymes of PMMA/hydroxyapatite nanocomposites/composites

In this study, polymer-ceramic nanocomposites and/or composites were prepared by solution removal method using poly(methylmethacrylat) (PMMA) and nano-hydroxyapatite (nHA). They were characterized using X-ray diffraction (XRD), Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR), and differential thermal analysis/thermogravimetry (DTA/TG). Their effects and biocompatibilities on antioxidant enzymes were also investigated in detail. It has been shown that nHA was dramatically dispersed at nanoscale in the polymer matrix. The interaction occurred between OH groups of nHA and carbonyl groups of polymer and introduction of ceramic into the polymer matrix generally resulted in an increase in thermal stability. Nanocomposites and composites had different effects on enzyme activities. Samples synthesized in acetone increased enzyme activities for glutathione reductase (GR) and glucose-6 phosphate dehydrogenase (G6PD) enzymes, while inhibiting glutathione peroxidase (GPx) and catalase (CAT) enzyme activities. On the other hand, samples synthesized in tetrahydrofuran (THF) exhibited inhibitory behavior for G6PD and CAT enzymes. The samples synthesized in different media did not show any regularity on enzyme activities. The nanocomposites and/or composites prepared in acetone media were better hemocompatible than those in THF.

First principles modeling of nanoparticle–polymer surface functionalizations for improved capacitive energy storage

Low energy density is the principle obstacle for widespread adoption of dielectric capacitors for large-scale energy storage, and in polymer–ceramic nanocomposite systems the root cause is dielectric breakdown at the nanoscale interface. Interfacial effects in composites cannot be observed directly, due to the long-range effects of the surrounding media and the internal nature of the defects, so we need to relate quantities we can calculate to macroscale properties. We demonstrate in silico a novel approach to evaluate surface coatings for dielectric polymer nanocomposites to determine their effect on electrical breakdown a priori. We look at the electric field at the interface of barium titanate nanoparticles, in a general way, using first principles of density functional theory. The calculated induced electric field of several surface functionalized polymer–ceramic nanocomposites, chosen based on their wide range of different chemical features, shows that 7-octenyltrimethoxysilane will have the most increased ultimate breakdown voltage. We also compare two previously used metrics for quantifying breakdown in composite materials, polarizability and band gap and discuss their limitations. Experimental results should be used to further refine our model because functionalization position is critical to the induced electric field, but this position is difficult to definitively determine computationally because of steric and other effects present in real systems. Combined with experimental inputs, our new approach could be used to dramatically reduce the cost and the number of experiments needed to find new composite materials.

Effect of directly added coupling agent on the dielectric properties of ceramic-polymer nanocomposites

Effect of directly added coupling agent on the dielectric properties of ceramic-polymer nanocomposites

Modification of Interfacial Interactions in Ceramic-Polymer Nanocomposites by Grafting: Morphology and Properties for Powder Injection Molding and Additive Manufacturing

The adhesion of the polymer to ceramic nanoparticles is a key aspect in the manufacturing of ceramic parts by additive manufacturing and injection molding, due to poor separation results in separation during processing. The purpose of this research is to investigate, by means of molecular dynamics simulations and experimental methods, the role of improved interfacial interactions by acrylic acid grafting-high density polyethylene on the adhesion to zirconia nanoparticles and on the composite properties. The polymer grafting results in high adhesion to the nanoparticles, increases the nanoparticles dispersion and improves the viscoelastic and mechanical properties required for additive manufacturing and injection molding.

High energy density with ultrahigh discharging efficiency obtained in ceramic-polymer nanocomposites using a non-ferroelectric polar polymer as matrix

To overcome the low discharging efficiency of ceramic-polymer composites using ferroelectric polymers as matrix and to take the advantage in fabrication offered by the polar polymer, a polar but non-ferroelectric polymer – poly(methyl methacrylate) (PMMA) – was selected as the matrix in the development of high performance composites for energy storage. Ba0.5Sr0.5TiO3 (BST) nanoparticles were selected as the filler. Freestanding and flexible BST-PMMA ceramic-polymer nanocomposites with BST content up to 30 vol.% were fabricated in thickness of about 5 μm using spin-coating process and were systemically studied. Due to the strong interaction between the polar groups of PMMA and the hydroxyl groups on the surface of BST nanoparticles, the suspension of BST nanoparticles in PMMA solution exhibits excellent stability and, hence, the nanocomposite films have excellent microstructure uniformity and compatibility between the BST nanoparticles and PMMA matrix. All the BST-PMMA films exhibit excellent frequency (100 Hz to 1 MHz) and temperature (−90 to 100 °C) stabilities in their dielectric properties with a high energy-storage density of more than 11 J/cm3. Most importantly, an ultra-high discharging efficiency of almost 100% is obtained in all the nanocomposites.

Dielectric properties of solution-processed BaTiO3–styrene butadiene styrene nanocomposite films

Polymer–ceramic nanocomposite films comprising ceramic nanoparticles dispersed in a polymer matrix (0–3 composites) have garnered increasing interest due to their superior performance characteristics, and can be used in flexible modern electronics and energy storage systems.

Glucose cross-linked hydrogels conjugate HA nanorods as bone scaffolds: Green synthesis, characterization and in vitro studies

In the expanding field of tissue engineering (TE), improvement of biodegradability and osteoconductivity of biomaterials are required. The use of non-toxic reagents during manufacturing processes is also necessary to decrease toxicity and increase cell viability in vivo. Herein, we present a novel approach to prepare hydroxyapatite (HA) nanorods from sea bio-wastes through a green and eco-friendly wet-chemical processing for bone TE. Highly porous natural polymer-ceramic nanocomposites made of HA, gelatin (Ge) and carboxymethyl cellulose (CMC) hydrogels are then introduced. It was found that cross-linking of the hydrogel matrix by glucose as a green reagent affected all characteristics of the scaffolds including pore size, swelling, biodegradability, and mechanical properties. The homogeneous microstructure with pore sizes in the range of 100–200 μm were attained at 10–20 wt% glucose concentration. With regard to stability and swelling in phosphate buffer saline (PBS), however, more glucose concentrations were desirable. The high biocompatibility and osteoblast activity of the scaffolds were assayed by MTT and calcium content on cell-cultured scaffolds with mesenchymal stem cells (MSCs). The developed CMC/Ge hydrogels modified with bio-derived HA nanorods have a great potential to be used for non-load bearing applications in bone TE.

Development of novel Bi1−xSmxFeO3 based polymer-ceramic nanocomposite for microwave application

Bismuth ferrite (BiFeO3) is a widely explored magneto electric ceramic whose properties can be enhanced through doping with a rare earth metal like samarium. Methoxy assisted sol–gel technique was used in the synthesis of pure phase bismuth ferrite and various concentrations of samarium doped bismuth ferrite Bi1−xSmxFeO3 where x = 0.05 and x = 0.1 (Bi0.95Sm0.05FeO3, Bi0.9Sm0.1FeO3) nanoparticles. The synthesized nanoparticles were characterized for their structural, morphological, and electrical behavior. The synthesized nanoparticles were used in the making of polymer-ceramic nanocomposite films by homogenous dispersion of the nanoparticles into the polyvinylacetate (PVA) polymer matrix. The developed Bi1−xSmxFeO3/PVA nanocomposite films were characterized for their structural, functional and dielectric characteristics that proved it to be used in the development of microwave devices for transient electronics. Based on the dielectric characterization, microstrip patch antennas were successfully designed, simulated and fabricated to function in the X Band (8 to 12 GHz) with polymer-ceramic (Bi1−xSmxFeO3/PVA) nanocomposite film as the substrate materials. The comparative analysis of the designed antennas showed excellent improvement in bandwidth and directivity. Bi1−xSmxFeO3/PVA nanocomposite films are found to be a favorable material for flexible transient electronics through controlled doping concentration.

Dielectric dispersion in CoFe2O4/PVDF nanocomposites influenced by ceramic contents and thermal mediation

Characteristics like high dielectric constants, ferroelectric and coupled magnetic behaviour when combined in multiferroic materials become quite essential for use in numerous applications including multi-functional devices and also as multi-layer ceramic capacitors. In this context, ceramic polymer nanocomposites of CoFe2O4/polyvilylidene difluoride (CFO/PVDF) are prepared in this work. Energy dispersive X-ray spectra of the samples confirmed the presence of elements in the exact stoichiometric ratio. A field emission scanning electron microscope revealed the minute details of the morphological features of the composite films. In the frequency range of 20 Hz to 20 MHz, as frequency is increased, the dielectric constant (real and imaginary) and tangent loss show a decrease but with the increase in temperature and CFO concentration, the dielectric features show an increase. Electro active regions, resistance and relaxation frequencies of the samples have been explained using complex impedance spectroscopy. As frequency and temperature is increased, the conductivity increases as a result, due to an increase in concentration of CFO nanoparticles. The electric field induced polarization studied by precision ferroelectric tester shows a decreasing trend from a maximum value as some of the samples can show conductivity because polarization versus electric field (P–E) loop is elliptical shaped and these properties are of tremendous value for industrial and commercial applications.

Influence of coupling agent on the microstructure and dielectric properties of free-standing ceramic-polymer composites

The influence of a commercial coupling agent on the dielectric properties and microstructure of ceramic-polymer nanocomposites are studied. Free-standing BaTiO3-P(VDF-CTFE) films were fabricated using a simple solution-casting process, and the good wettability between fillers and polymer matrix was obtained by using 3-Aminopropyltriethoxysilane as coupling agent. It is found that the coating of a small amount of coupling agent on the surface of BaTiO3 fillers results in an enhanced dielectric constant, a higher breakdown strength and a larger energy-storage efficiency. When an excessive amount of coupling agent was used, the non-attached coupling agent molecules participated in the complex reactions and result in the aggregation of fillers and the reduction of dielectric constant. It is also found that the surface modification of fillers has a complicated influence on its dielectric behavior which leads to an increase in the dielectric loss of the nanocomposites. When an appropriate amount of coupling agent is coated on fillers, the energy storage density of the nanocomposite is improved due to the enhanced dielectric constant and higher breakdown strength. A maximal discharged energy-storage density of about 4.0 J cm−3 was obtained from the nanocomposite film containing 15 vol% of surface modified BaTiO3 fillers with 1 wt% of KH550, which is about 3 times of that for the nanocomposite without coupling agent.