Download or read book Understanding the Effects of Defect Modification on the Structure and Properties of Fluorinated Polymers and Implications for Capacitive Energy Storage Technologies written by Matthew Gadinski and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the world begins to turn to alternative energy technologies and our electronic devices have become more both mobile and integral to everyday life, increasing interest has been focused on energy storage technologies. Capacitors are one of these energy storage technologies that utilize the polarization of an insulating material sandwiched by two electrodes as a means to store electric charge. Polymers are a preferred dielectric material for capacitors because of both their performance and practicality. However, polymer dielectrics are limited in energy density by low dielectric constant, and high loss at elevated temperature. This work aims to address these issues in order to enable polymer dielectrics for future applications and demands. As most polymer tend to have low dielectric constants (~2-3), but impressive breakdown strengths, only a moderate improvement in dielectric constant has the potential to vastly improve the energy density of polymer capacitors. As such tremendous interest has been placed on poly(vinylidene fluoride) (PVDF) which has a dielectric of 10+ due to the highly polar C-F bonds of its backbone. To improve PVDF's performance defect monomers have been introduced to tailor the polymorphic crystalline phase to tune its properties. Additionally, this defect modification has implications for piezoelectric, electrocaloric, and thermoelectric applications of PVDFIn Chapter 2 a copolymer of VDF and bromotrifluoroethylene (BTFE) was produced. The effect of BTFE on the structure and dielectric properties of the resulting copolymer had not been previously evaluated, and its synthesis allowed for the comparison to previously reported VDF based copolymers including P(VDF-CTFE) and P(VDF-HFP). Through 19F NMR it was determined due to reactivity ratio differences of BTFE in comparison to previously explored copolymers, BTFE during synthesis is much more likely to link with itself. This results in long runs of BTFE-BTFE defects along with isolated single defects. These long runs are found to have dramatic effects on the distribution of chain conformations determined from FTIR, the melting temperature and total crystallinity determined by DSC, and the crystallite size, lattice spacing, and crystalline phase as determined by XRD. These results indicate that P(VDF-BTFE) has a mix of both included (single) and excluded defects (runs of defects) that rapidly inhibit crystallinity and alter phase. The dielectric analysis also confirmed this by a broadening of the Tg peak in the temperature dependent dielectric spectroscopy with increasing BTFE content in the monomer feed indicative of expansion of the interlamellar region due to defect exclusion.Chapter 3 explores P(VDF-BTFE) copolymers for capacitive energy storage. Due to the rapid decrease in crystallinity only low concentration copolymers (>2 mol %) BTFE were used. This was ultimately a result of stretching being required for high energy density to be exhibited. The 0.5 mol% BTFE copolymer samples was found to possess a discharge energy density of 20.8 J/cm3 at 750 MV/m along with the highest breakdown strength of any reported PVDF based copolymer. It was found that for this small amount of defect monomer the [gamma] phase of PVDF was stabilized and mixed with [beta] phase and along with small crystallite size accounted for the high breakdown strength and energy density. Additionally, by utilizing only a small amount of defect monomer the decrease in crystallinity and melting temperature observed in previously examined PVDF copolymers was avoided.Chapter 4 examines a terpolymer of VDF, trifluoroethylene (TrFE), and chlorotrifluoroethylene (CTFE). The terpolymers of VDF have gained extensive interest as the use of the two defect monomer increases the dielectric constant to 40+ along with altering the polarization behavior from a normal ferroelectric to a relaxor ferroelectric characterized by a slim hysteresis loop. The current understanding of this behavior suggests that only the size of the third bulky monomer (CTFE in this case) determines whether a single hysteresis (SHL) or double hysteresis loop (DHL) will develop. This chapter shows that for a single composition of the terpolymer normal ferroelectric, SHL, and DHL behavior can be tuned through processing of the film. This was rationalized as films give long times to crystallize developed large ferroelectric domains within a paraelectric matrix resulting in the DHL behavior due to reversible switching of these domains. While if these films were stretched below the Tc SHL behavior was observed as this had the effect of dispersing these domains within the crystal. Chapter 5 changes focus to high temperature performance of polymer capacitors. The primary strategy to enable high temperature polymer capacitors has been the utilization of high Tg polymers because of their thermal stability. While these polymers have demonstrated stable dielectric properties at low field and high breakdown strengths at elevated temperatures, the high field loss limits their use at even mildly elevated temperature well below Tg. Additionally, these polymers are expensive, brittle, and difficult to process, essentially defeating some of the primary reasons for utilizing a polymer in the first place. This chapter examines a commercially available, extrudable, high temperature fluoropolymer, known as polychlorotrifluoroethylene (PCTFE). The same defect monomer discussed with PVDF above. While this polymer showed comparable performance to BOPP at room temperature, it showed equally susceptible to high field loss at elevated temperature. However, the chlorine of the monomers allow for crosslinking of this polymer by commercially used peroxide/co-agent chemistry. Crosslinking lead to a substantial improvement of the crosslinked film over the pristine polymer, and superior energy density to the commercial high Tg polymers up to 150 °C. The reason for the improvement was found to be the formation of chemical defects produced during the crosslinking that were excluded from the crystalline phase. Through TSDC it was found that these defects concentrated in the interlamellar region led to a substantial enhancement of the charge trapping properties of this relaxation.

Download or read book Handbook of Specialty Fluorinated Polymers written by Susanta Banerjee and published by William Andrew. This book was released on 2015-04-24 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluoropolymers are used in applications demanding service at enhanced temperature while maintaining their structural integrity and have excellent combination of chemical, physical and mechanical properties. Advancements in materials and processing technology mean that a huge amount of research is currently taking place into new, high performance applications for specialty fluorinated polymers. This book is a complete review of the current research in synthesizing new fluorinated high performance polymers and their application in the field of low dielectric constant materials, membrane based separation (gas and liquid) and proton exchange membranes. Special emphasis is given to the preparation of soluble high performance polymers by incorporating fluorine and different structural elements so as to use these classes of polymers in different membrane based applications, including low dielectric constant materials, gas separation, pervaporation, proton exchange membranes in fuel cells, and more. The coverage of processing properties and commercial aspects - as well as a practical assessment of the advantages and disadvantages of specialty fluoropolymers compared to other materials - enables engineers and product designers to apply the latest scientific developments in this area in a practical setting. Thorough coverage of modern applications for specialty fluorinated polymers, including membranes and coatings – giving insight into recent research and the future direction of this technology Brings researchers and engineers up to date with the latest developments in specialty fluoropolymers, to assist in future materials research and part design Includes detailed assessment of the advantages and shortcomings of specialty fluorinated polymers, for ease of comparison with alternative materials

Download or read book Technology of Fluoropolymers written by Jiri George Drobny and published by CRC Press. This book was released on 2014-10-31 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since Plunkett's discovery of Teflon (PTFE) in 1938, many new types of fluorine-containing polymers have been developed, especially during last two decades. The worldwide annual production capacity for fluoropolymers is estimated to be 135,000 metric tons. Continuing research and development provides new and interesting products that will help adva

Download or read book Understanding the Composition structure property Relationships and Enhancing the Electromechanical Responses in Ferroelectric Polymers written by Zhubing Han and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Poly(vinylidene fluoride) (PVDF)-based ferroelectric polymers enable a wide range of advanced applications with new functionalities and structure designs due to their high electroactivity, intrinsic flexibility and biocompatibility. One unique feature of these polymers is that their dielectric, ferroelectric and electromechanical properties can be modulated by varying their chemical composition and the processing conditions. Despite the progress over the last decades, a more comprehensive understanding on the composition--structure--property relationships in PVDF-based ferroelectric polymers is still needed to achieve rational design of new materials with enhanced performance. The scope of this dissertation aims to understand the influence of monomer defects on the structures and ferroelectric properties of PVDF-based terpolymers, and to enhance their electromechanical performance enabled by the rational design of new polymer structures and compositions. After a general background introduction, the dissertation starts with two chapters discussing the effect of two different comonomers as chain defects on the structures and ferroelectric properties of the corresponding terpolymers. Chapter 2 reveals that the incorporation of bulky 2-chloro-1,1-difluoroethylene (CDFE) can gradually convert the ferroelectric P(VDF-TrFE) (TrFE: trifluoroethylene) into a relaxor ferroelectric terpolymer as confirmed by the dielectric and structural characterizations. The CDFE comonomer serves as an effective chain defect to destabilize the ferroelectric domain by introducing the gauche conformation. The P(VDF-TrFE-CDFE) with 3.8 mol% CDFE exhibits typically relaxor ferroelectric behaviors such as strong frequency-dependence of dielectric properties, broad and diffuse ferroelectric phase transition, and weak remanent polarization. Chapter 3 systematically investigates the effect of another comonomer defect, vinyl fluoride (VF), which has a smaller size than VDF. It is found that VF plays an opposite role compared with the bulky chlorinated comonomers. Increasing molar content of VF leads to an increase in the Curie temperature and the coercive field of the terpolymers. Structural characterizations and simulations evidences confirm that the all-trans conformation remain energetically more favored than the gauche conformation regardless of the VF content. The results stress the vital role of comonomer structure and size in modulating the structures and properties of the ferroelectric polymers. The next two chapters focus on improving the electromechanical performance of the PVDF-based polymers. In Chapter 4, a series P(VDF-TrFE-CTFE) (CTFE: chlorotrifluoroethylene) with systematic composition variations have been synthesized. Structural characterizations show that the terpolymers with 1.7 to 5.0 mol% CTFE exhibit a mixture and competition of the normal ferroelectric and relaxor ferroelectric phases as a result of the incorporation of CTFE. Specifically, a maximum longitudinal piezoelectric coefficient (d33) of -55.4 pm/V has been observed in P(VDF-TrFE-CTFE) 64.5/33.1/2.4 mol%, corresponding to an 85% improvement compared with the commercial benchmark P(VDF-TrFE) 65/35 mol%. This strategy can potentially be expanded to other polymer systems to improve the piezoelectric response. Chapter 5 aims to enhance the low-electric-field electrostrictive strain in relaxor ferroelectric polymers. The small electrostrain of current relaxor ferroelectric P(VDF-TrFE-CFE) (CFE: 1-chloro-1-fluoroethylene) and P(VDF-TrFE-CTFE) terpolymers at low electric field impedes their usefulness in actuating devices. In situ structural characterizations under the electric field reveal that the electrostrictive strain originates from the field-induced phase transition in P(VDF-TrFE-CFE) and the lattice compression in P(VDF-TrFE-CTFE). Inspired by the distinct functions of CFE and CTFE, a series of P(VDF-TrFE-CFE-CTFE) tetrapolymers have been synthesized, which exhibit significant enhancement of electrostrictive strain at both low and high electric fields due to the synergistic effect of CFE and CTFE. These results provide new insight into the origin of electrostriction in the relaxor ferroelectric polymers, and the tetrapolymers in this study can potentially be used to prototype soft actuators. It is anticipated that the materials, methodologies and results developed in this dissertation will not only provide new insights and understandings on the structure-property relationship in ferroelectric polymers, but also stimulate future work to further enhance the performance in these materials in order to meet the material requirement for practical applications.

Download or read book Electrode Materials for Energy Storage and Conversion written by Mesfin A. Kebede and published by CRC Press. This book was released on 2021-11-17 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the latest developments and materials used in electrochemical energy storage and conversion devices, including lithium-ion batteries, sodium-ion batteries, zinc-ion batteries, supercapacitors and conversion materials for solar and fuel cells. Chapters introduce the technologies behind each material, in addition to the fundamental principles of the devices, and their wider impact and contribution to the field. This book will be an ideal reference for researchers and individuals working in industries based on energy storage and conversion technologies across physics, chemistry and engineering. FEATURES Edited by established authorities, with chapter contributions from subject-area specialists Provides a comprehensive review of the field Up to date with the latest developments and research Editors Dr. Mesfin A. Kebede obtained his PhD in Metallurgical Engineering from Inha University, South Korea. He is now a principal research scientist at Energy Centre of Council for Scientific and Industrial Research (CSIR), South Africa. He was previously an assistant professor in the Department of Applied Physics and Materials Science at Hawassa University, Ethiopia. His extensive research experience covers the use of electrode materials for energy storage and energy conversion. Prof. Fabian I. Ezema is a professor at the University of Nigeria, Nsukka. He obtained his PhD in Physics and Astronomy from University of Nigeria, Nsukka. His research focuses on several areas of materials science with an emphasis on energy applications, specifically electrode materials for energy conversion and storage.

Download or read book OAR written by and published by . This book was released on 1967 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Perovskite Metal Oxides written by Srikanta Moharana and published by Elsevier. This book was released on 2023-05-30 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite Metal Oxides: Synthesis, Properties and Applications provides an overview on the topic, including the synthesis of various types of perovskites, their properties, characterization and application. The book reviews the applications of this category of materials for photovoltaics, electronics, biomedical, fuel cell, photocatalyst, sensor, energy storage and catalysis, along with processing techniques of perovskite metal oxides with a focus on low-cost and high-efficiency methods, including various properties and probable applications in academia and industry. Other sections discuss strategies to improve the functionality of perovskite metal oxide materials, including chemical methods and controlling the size, shape and structure of the materials. Finally, applications of perovskite metal oxides in energy conversion and storage, sensing and electronics are covered. Provides an overview of perovskite metal oxides, with an emphasis on synthesis, fabrication and characterization methods Discusses strategies to improve the functionality of perovskite metal oxide materials, including chemical methods and controlling the size, shape and structure of the materials Reviews applications of perovskite metal oxides in energy conversion and storage, sensing and electronics

Download or read book Air Force Research Resum s written by and published by . This book was released on with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dielectric Polymer Materials for High Density Energy Storage written by Zhi-Min Dang and published by William Andrew. This book was released on 2018-06-13 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dielectric Polymer Materials for High-Density Energy Storage begins by introducing the fundamentals and basic theories on the dielectric behavior of material. It then discusses key issues on the design and preparation of dielectric polymer materials with strong energy storage properties, including their characterization, properties and manipulation. The latest methods, techniques and applications are explained in detail regarding this rapidly developing area. The book will support the work of academic researchers and graduate students, as well as engineers and materials scientists working in industrial research and development. In addition, it will be highly valuable to those directly involved in the fabrication of capacitors in industry, and to researchers across the areas of materials science, polymer science, materials chemistry, and nanomaterials. Focuses on how to design and prepare dielectric polymer materials with strong energy storage properties Includes new techniques for adjusting the properties of dielectric polymer materials Presents a thorough review of the state-of-the-art in the field of dielectric polymer materials, providing valuable insights into potential avenues of development

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrical Degradation and Breakdown in Polymers written by Len A. Dissado and published by IET. This book was released on 1992 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is in five parts: Part I introduces the physical and chemical structure of polymers and their breakdown; Part II reviews electrical degradation in polymers, and Part III reviews conduction and deterministic breakdown in solids. Part IV discusses the stochastic nature of break-down from empirical and modelling viewpoints, and Part V indicates practical implications and strategies for engineers. Much of the discussion applies to non-crystalline materials generally.

Download or read book Air Force Research Resum s written by and published by . This book was released on 1966 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomic Layer Deposition for Semiconductors written by Cheol Seong Hwang and published by Springer Science & Business Media. This book was released on 2013-10-18 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering thorough coverage of atomic layer deposition (ALD), this book moves from basic chemistry of ALD and modeling of processes to examine ALD in memory, logic devices and machines. Reviews history, operating principles and ALD processes for each device.

Download or read book Conference Papers Index written by and published by . This book was released on 1987 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Air Force Research Resum s written by United States. Air Force. Office of Aerospace Research and published by . This book was released on 1966 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anelastic and Dielectric Effects in Polymeric Solids written by N. G. McCrum and published by . This book was released on 1967 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book BTL Talks and Papers written by Bell Telephone Laboratories, inc. Technical Information Libraries and published by . This book was released on 1980 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: