Dielectric Spectroscopy of Polymer-Based Nanocomposite Dielectrics with Tailored Interfaces and Structured Spatial Distribution of Fillers (original) (raw)
Polymer Nanocomposite Dielectrics – The Role of the
Dielectrics and …, 2005
The incorporation of silica nanoparticles into polyethylene increased the breakdown strength and voltage endurance significantly compared to the incorporation of micron scale fillers. In addition, dielectric spectroscopy showed a decrease in dielectric permittivity for the nanocomposite over the base polymer, and changes in the space charge distribution and dynamics have been documented. The most significant difference between micron scale and nanoscale fillers is the tremendous increase in interfacial area in nanocomposites. Because the interfacial region (interaction zone) is likely to be pivotal in controlling properties, the bonding between the silica and polyethylene was characterized using Fourier Transformed Infra-red (FTIR) spectroscopy, Electron Paramagnetic Resonance (EPR), and X-ray Photoelectron Spectroscopy (XPS) The picture which is emerging suggests that the enhanced interfacial zone, in addition to particle-polymer bonding, plays a very important role in determining the dielectric behavior of nanocomposites.
Dynamics and dielectric properties of polymer/nanoparticle nanocomposites by dielectric spectroscopy
Dynamics and dielec. properties of nanocomposites based on polymer matrixes and different types of nanoparticles, as studied by several authors, have been reviewed. Studies on nanocomposites based both on thermoplastic (conductive, non conductive and liq. crystals) and thermosetting matrixes are presented, with several types of nanoparticles (ceramic, metallic, metal oxide and others) as fillers. Their effect on dielec. properties and mol. dynamics has been analyzed, underlaying the strong effect of the interfaces on them. Theor. models such as those corresponding to the percolation theory proposed by several authors to quantify those effects are presented and compared, discussing the values and evolution of the fitting parameters.
Studies on dielectric properties of a conducting polymer nanocomposite system
2008
Dielectric analysis of ion conducting solid polymer nanocomposite has been investigated as a function of temperature and frequency. Effect of clay concentration in changing the dielectric relaxation behaviour of polymer salt complex film is clearly visible, observed in terms of changes in polymer chain relaxation and dipolar contribution due to ion pairs. An enhancement in relative permittivity by 2 orders of magnitude has been recorded at room temperature in nanocomposite films controlled predominantly by clay concentration. Almost similar behaviour has been observed after crystalline to amorphous phase transition temperature at T ≥70°C for both polymer salt complex and nanocomposite films irrespective of clay concentration. A lowering of relaxation time, attributed to relaxing dipoles, with clay concentration suggests faster ion dynamics in nanocomposite films.
The Promise of Dielectric Nanocomposites
Conference Record of the 2006 IEEE International Symposium on Electrical Insulation, 2006
Several research groups worldwide have now been able to document some significant improvements that can be made in the electrical, and other, properties of polymer composites through the incorporation of nanoparticulates. Although it is now becoming clear that the mechanisms responsible for these changes are by no means universal, some of the benefits are substantial and rely on the large interface areas which are inherent in the introduction of materials of nanometric dimensions. By examining a variety of nanomaterials, this contribution seeks to review the property changes that can be brought about and examines the possibilities for commercial applications. This involves not only the electrical properties, but the implications for the attendant mechanical characteristics and the polymer processing necessary for utilization of this emerging breed of dielectric material. In this context, the functionalization of the particulate surfaces to provide preferential coupling to the host polymer will be explored since, by this means, a degree of preferred assembly can be accommodated. Through experimental examples, the use of this technique to tailor the properties of nanodielectrics is illustrated.
Recent advances in rational design of polymer nanocomposite dielectrics for energy storage
Nano Energy, 2020
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Journal of Composites Science
Polymer blend or composite, which is a combination of two or more polymers and fillers such as semiconductors, metals, metal oxides, salts and ceramics, are a synthesized product facilitating improved, augmented or customized properties, and have widespread applications for the achievement of functional materials. Polymer materials with embedded inorganic fillers are significantly appealing for challenging and outstanding electric, dielectric, optical and mechanical applications involving magnetic features. In particular, a polymer matrix exhibiting large values of dielectric constant (ε′) with suitable thermal stability and low dielectric constant values of polymer blend, having lesser thermal stability, together offer significant advantages in electronic packaging and other such applications in different fields. In this review paper, we focused on the key factors affecting the dielectric properties and its strength in thin film of inorganic materials loaded poly methyl meth acryla...
DIELECTRIC POLYMERS NANOCOMPOSITES FOR STORAGE ENERGY APPLICATIONS
The ability to store large amounts of energy with a simple device that has a long useful life makes capacitors an attractive for the future of electric power storage option. However, the low permittivity, has prevented its application in many applications, including electric vehicles and electronic devices. The ceramic and polymer are being perfected for storing energy, though, the limits of dielectric prevent that can be used for high energy storage applications. Because of this, the ceramic composites and polymers have been of great interest, as they have an improved dielectric constant and dielectric strength. This paper presents a brief introduction to the dielectric polymer nanocomposites for energy storage applications, describing the most important properties of these materials, a description of the most commonly used dielectrics and polymeric nanocomposites improvements over traditional dielectrics.
Polymer nanodielectrics—Short history and future perspective
Journal of Applied Physics
This article provides a perspective on the development of polymer nanodielectrics for electrical insulation applications. It includes a short history of the development of the field, barriers to implementation, a chemical toolbox available for optimizing properties, some examples of potential commercial development, and the latest advances. It offers opinions on critical research needed to fully develop the models needed to predict behavior and to develop design tools. Key findings include the need for: quantification of nanofiller dispersion, investment in long term aging data research, better scale up methods, a data resource that brings the broad data together in a format that enables faster scientific discovery, and a commercial entitity willing to take the risk in implementing these promising materials.
2020 IEEE 3rd International Conference on Dielectrics (ICD), 2020
Polymer composites with PVdF-HFP matrix and BaTiO3 nanoparticles were prepared with different dispersion states to evaluate the impact of the dispersion state of the nanoparticles on dielectric properties. We observe that the dispersion state has two effects: first, the overall dielectric permittivity is a little higher in aggregated systems than in welldispersed systems; Second, conductivity, together with a capacitive contribution, increase at low frequencies in aggregated systems as compared to well-dispersed systems. We propose that polarization couplings may enhance the effective permittivity in aggregated systems, and that Maxwell-Wagner-Sillars polarization may also contribute at low frequencies due to local percolation of the particles.
Macromolecules, 2017
Probing the properties of the interfacial layer between the polymer matrix and nanoparticles in polymer nanocomposites (PNCs) remains a challenging task. Here, we apply three methodsa single Havriliak−Negami (HN) function fit, a two HN functions fit, and the heterogeneous model analysis (HMA)to analyze the dielectric spectra of model poly(vinyl acetate)/SiO 2 nanocomposites for the thickness and the average slowing down in dynamics of the interfacial layer. We find the HMA presents the most accurate analysis on both the thickness and dynamics of the interfacial layer, in comparison to the other two methods that have been actively applied in the field. In addition, the dielectric spectra at low temperatures reveal unexpectedly nonmonotonous changes in the secondary relaxation of the polymer with nanoparticle loadings. These results clearly demonstrate that dielectric spectroscopy is an easy and robust method to study a wide range of dynamic properties of the interfacial layer in PNCs.
Composites Science and Technology, 2018
The polymer nanocomposites have potential applications in flexible electronics due to its interesting dielectric properties. Hence, flexible nanocomposite films of polyvinylidene fluoride (PVDF) polymer and barium hexaferrite (BHF) nanoparticles with high dielectric constant were prepared by the solution cast method. The dielectric behavior of the materials has been understood by employing the impedance spectroscopy techniqe. The coexistence of α and β phases of PVDF has been observed from the XRD (X-ray Diffractometer) and FTIR (Fourier-transform infrared spectroscopy) analysis. The ratio of α and β phases of PVDF has a great influence on dielectric, ferroelectric and energy storage density of PVDF-BHF nanocomposites and, it depends upon the concentration of BHF in the nanocomposites. FE-SEM (Field Emission Scanning Electron Microscopy) micrographs reveal that the microstructure of the composite depends upon the concentration of BHF in the PVDF matrix. Dielectric properties of nanocomposite highly depends on microstructure of the PVDF-BHF nanocomposite. This observation has been well explained by considering the BLCs (Barrier Layer capacitances) model. Interestingly, the dielectric constant has been enhanced eighteen (18) times at 1KHz to that of dielectric constant of PVDF. The dielectric constant increases due to the electrostatics and interfacial interaction between the local electric field of the BHF nanoparticle and CH2/CF2 dipole of PVDF chain. The present study opens a new window for the possible use of PVDF-BHF nanocomposite in dielectric and energy storage device applications.
Dielectric properties of polymer nanoparticle composites
Polymer, 2007
Well-dispersed high dielectric permittivity titanium dioxide (TiO 2 ) nanoparticles were synthesized utilizing a block copolymer as a template. The nanoparticles were confined within microphase separated domains of sulfonated styrene-b-(ethylene-ran-butylene)-b-styrene (S-SEBS) block copolymers. A crosslinker (vinyltrimethoxysilane) was incorporated into the block copolymer matrices in order to decrease the dielectric loss from the free sulfonic acid groups. Dynamic mechanical analysis experiments confirmed that nanoparticles and crosslinker were confined within the crosslinked sulfonated styrene blocks and had no effect on the chain relaxation behavior of [ethylene-ran-butylene] blocks. Dielectric experiments showed that higher permittivity composites can thus be obtained with a significant decrease in loss tan d (<0.01) when crosslinked with vinyltrimethoxysilane.
Role of the interface in determining the dielectric properties of nanocomposites
The 17th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2004. LEOS 2004.
It has been demonstrated that the electrical breakdown properties of polymer composites can be substantially enhanced when the filler particles are of nanometric dimensions. These benefits are likely related to the mitigation and redistribution of internal charge. Using the example of an epoxy-TiO 2 nanodielectric (and a comparable conventional composite), this contribution seeks to examine this issue from the physical and chemical viewpoint. It is shown that a reduction in free volume cannot be used to explain the dielectric enhancements. The free volume of nanomaterials is actually higher than that of conventional samples. This conclusion is consistent with recent application of electron paramagnetic resonance methods, which have confirmed earlier speculation that the environment associated with the interface is radically changed when the in-filled particulates are reduced to nanometric dimensions and the associated interfacial area is greatly increased. Through examinations of infrared absorption & EPR, the paper provides some speculation on the part played by an interaction zone surrounding the particulate inclusions. The presence of a highly mobile interlayer is thought to be the key to the electrical property changes seen.
Candidate Mechanisms Responsible for Property Changes in Dielectric Nanocomposites
2006
This contribution seeks to provide some insight for the documented changes in the electrical properties of filled polymers when the filler size is reduced to nanometric dimensions. After examining the possible underlying mechanisms, experiments are described in which composites based on a benign biphenol epoxy resin formulation are subjected to photo- and electro-luminescence studies in which the spectrum of the
Broadband Dielectric Relaxation Spectroscopy in Polymer Nanocomposites
Macromolecular Symposia, 2008
Dielectric spectroscopy in the frequency domain and thermally stimulated depolarization currents techniques, covering together a broad frequency range (10 À4 -10 9 Hz), were employed to investigate molecular dynamics in relation to structure and morphology in polymeric nanocomposites. Several systems were investigated, three of them with the same epoxy resin matrix and different inclusions (modified smectite clay, conducting carbon nanoparticles and diamond nanoparticles) and two with silica nanofiller (styrene-butadiene rubber/silica and polyimide/ silica nanocomposites). Special attention was paid to the investigation of segmental dynamics associated with the glass transition of the polymer matrix, in combination also with differential scanning calorimetry measurements. Effects of nanoparticles on local (secondary) relaxations and on the overall dielectric behavior were, however, also investigated. Several interesting results were obtained and discussed for each of the particular systems. Two opposite effects seem to be common to the nanocomposites studied and dominate their behavior: (1) immobilization/reduction of mobility of a fraction of the chains at the interface to the inorganic nanoparticles, due to chemical or physical bonds with the particles, and (2) loosened molecular packing of the chains, due to tethering and geometrical confinement, resulting in an increase of free volume and of molecular mobility.
2019
Nanocomposites based on polyethyl methacrylate (PEMA) and polyvinyl chloride with different materials (Barium zirconate (BaZrO3), silicon dioxide (SiO2), and MMT etc) had been prepared. Scanning electron microscope (SEM) has been used for morphological characterization of PEMA/BaZrO3, PVC/MMT, PVC/SiO2 and PVC/MMT/SiO2 nanoparticles in order to confirm the nano-dispersion and their effect on morphology changes in PEMA and PVC matrix. Various properties primarily based on these substances were investigated by way of dielectric characteristics. The dielectric traits were strongly prompted via a spread of the nanoparticles and might be analysed using the frequency and temperature based interfacial relaxation. The maximum value of energy density for PEMA+6wt.% BaZrO3 nanocomposite at room temperature as compare to PVC nanocomposites has been observed. These efficient polymeric matrices based nanocomposites could be applied as efficient dielectric materials in the various electronic applications.
Revue Roumaine de Chimie, 2021
In this study, a comparative study of nanocomposites with treated and untreated metal oxide nanoparticules using a plastograph was investigated. Stearic acid and co-mixing technique were chosen as a fast technique to ensure the dispersion of the filler into the polymeric matrix. Fillers were mechanically treated and co-mixed with stearic acid using kitchen coffee grinder and the mixture was then added to the polymeric matrix in a Brabender plastograph with various contents of 0.5 wt. %, 1 wt. % and 2 wt. %. The method effectiveness has been proved by AFM analysis. The results showed that the incorporation of inorganic semiconductor nanoparticles into polymeric matrix improves the dielectric properties. Results showed that with the co-mixing process and stearic acid the inorganic nanofillers have a strong influence on the permittivity of resulting nanocomposites.
Nanofiller Dispersion in Polymer Dielectrics
Materials Sciences and Applications, 2013
Nanodielectric composites have been developed in recent years attempting to improve the dielectric properties such as dielectric constant, dielectric strength and voltage endurance. Among various investigations, nanoparticle dispersion was particularly emphasized in this work. General Electric Global Research Center in Niskayuna NY USA has investigated various nanoparticles, nanocomposites and nanocomposite synthesis methods intending to understand particle dispersion and their impact on the nanocomposite dielectric properties. The breakdown strength and microstructures of the nanocomposites containing different particles were studied for projects related to capacitor and electrical insulation technologies. The nanocomposite synthesis methods either employed commerical nanoparticles or utilized nanoparticles that were self-assembled (in-situ precipitation) in a matrix. Our investigations have shown that nanocomposites prepared with solution chemistry were more favorable for producing uniform dispersion of nanoparticles. Structural information of nanocomposites was studied with transmission electron microscopy and the interection between particles and matrix polymers were tentatively probed using dielectric spectroscopy. In these new class of materials high energy densities on the order of 15J/cc were achievable in nanocomposites.