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 Structure property Correlations in Compositionally Complex Ferroelectrics written by Abinash Kumar and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compositional control in functional oxides can significantly alter material properties and lead to the emergence of unconventional behavior. Ferroelectrics with switchable polar ordering, for instance, are influenced by local compositional variation, thus requiring an understanding of structure-property relationships. My dissertation work focuses on using atomic scale characterization with an aberration-corrected scanning transmission electron microscope (STEM) to determine these structure-property correlations in two compositionally complex ferroelectric systems: compositionally heterogeneous relaxors and stoichiometry-controlled orthoferrites. Relaxor ferroelectrics show exceptional electromechanical response, energy storage capacity, and electrocaloric properties, finding applications ranging from ultrasound imaging to electrical energy storage systems. These materials show nanoscale chemical and structural heterogeneity that make finding the origin of their exceptional properties a seemingly intractable problem. Here, I utilize STEM to quantify various types of nanoscale heterogeneities and determine their correlation with the nanoscale polar domain structure in a prototypical relaxor ferroelectric system Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT). I determined three types of heterogeneities: chemical order, oxygen octahedral tilt order, and oxygen octahedral distortion order. These heterogeneities vary with Ti content and show spatial correlation with low-angle domain walls, indicating their role in breaking down the long-range polar order and stabilizing the nanoscale domain structure essential for the relaxor response. I identified monoclinic-like distortions, which are related to both the Ti content and electromechanical response. The connection among heterogeneities in local chemistry, structure, and polarization is revealed through comprehensive STEM characterization. These experimental results also validate theoretical models proposed since the discovery of relaxors. Further, due to the extensive demand for miniaturization of modern electronic devices, relaxor ferroelectrics are desired in their thin film forms. This requires a detailed study on the growth and characterization of compositionally heterogeneous relaxor ferroelectrics thin film. Consequently, investigating nanoscale domain structures under different conditions such as epitaxial strain is possible in thin films. With chemical and structural heterogeneities determining polar structure in bulk relaxors, their spatial distribution and behavior need to be determined to relate structure with properties in thin films. I determine the distribution of local chemistry and their role in the evolution of polar structure across thickness in PMN-PT relaxor thin films grown with pulsed-laser deposition (PLD). Further, I quantify the effect of epitaxial compressive strain in terms of the evolution of polar structure and chemical heterogeneities to explain the structural origin of decreasing relaxor behavior with strain. With an increase in epitaxial strain, the size of polar domains and chemical ordered regions increases along the film growth direction, yet the coupling among local chemistry and structure on a unit cell basis diminishes, thus showing poor relaxor response at highly strained films. The second ferroelectric system of the interest is orthoferrites. These have been shown as potential single-phase multiferroic materials with the coexistence of both ferroelectric and magnetic ordering. These materials have unconventional ferroelectric behavior irrespective of their centrosymmetric structure in bulk form. Orthoferrite YFeO3 (YFO) thin films even show composition-dependent ferroelectricity. Y-rich YFO thin films reveal ferroelectric behavior while Fe-rich films show no ferroelectric response, with the structural origins of such behavior yet to be determined. Here, I use STEM to probe the atomic structure and elemental distribution in stoichiometry-controlled YFO thin films grown by PLD. I determine Y[subscript Fe] antisites in Y-rich YFO thin films that are absent in Fe-rich films. These antisites modify the structure and break the local symmetry, stabilizing the ferroelectric ordering. In addition, planar defects such as antiphase boundaries (APBs) are also found in Y-rich YFO, which show large structural relaxations. Despite Y-rich composition, these APBs also host FeY antisites, exhibiting bi-stable polar distortions. Density functional theory predicts the formation energy and polarization switching barrier reduces by a factor of three at these APBs, thus leading to changes in local properties. In the Y-rich YFO films, APBs show significantly lower density than Y subscript Fe antisites, indicating the ferroelectric response arises predominantly from Y[subscript Fe] antisites. These results reveal that defect engineering achieved via stoichiometry control allows tuning properties in functional orthoferrites.
Download or read book Piezoelectric Energy Harvesting written by Alper Erturk and published by John Wiley & Sons. This book was released on 2011-04-04 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.
Download or read book Ferroelectric Polymers written by Hari Singh Nalwa and published by CRC Press. This book was released on 1995-06-20 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work covers the chemistry and physics of polymeric materials and their uses in the fields of electronics, photonics, and biomedical engineering. It discusses the relationship between polymeric supermolecular structures and ferroelectric, piezoelectric and pyroelectric properties.
Download or read book Electromechanically Active Polymers written by Federico Carpi and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ferroelectric Domain Walls written by Jill Guyonnet and published by Springer Science & Business Media. This book was released on 2014-04-08 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the nano metric resolution of atomic force microscopy techniques, this work explores the rich fundamental physics and novel functionalities of domain walls in ferroelectric materials, the nano scale interfaces separating regions of differently oriented spontaneous polarization. Due to the local symmetry-breaking caused by the change in polarization, domain walls are found to possess an unexpected lateral piezoelectric response, even when this is symmetry-forbidden in the parent material. This has interesting potential applications in electromechanical devices based on ferroelectric domain patterning. Moreover, electrical conduction is shown to arise at domain walls in otherwise insulating lead zirconate titanate, the first such observation outside of multiferroic bismuth ferrite, due to the tendency of the walls to localize defects. The role of defects is then explored in the theoretical framework of disordered elastic interfaces possessing a characteristic roughness scaling and complex dynamic response. It is shown that the heterogeneous disorder landscape in ferroelectric thin films leads to a breakdown of the usual self-affine roughness, possibly related to strong pinning at individual defects. Finally, the roles of varying environmental conditions and defect densities in domain switching are explored and shown to be adequately modelled as a competition between screening effects and pinning.
Download or read book Properties of Materials written by Robert E. Newnham and published by Oxford University Press on Demand. This book was released on 2005 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensors, matrices, symmetry, and structure-property relationships form the main subjects of the book. While tensors and matrices provide the mathematical framework for understanding anistropy, on which the physical and chemical properties of crystals and textured materials often depend, atomistic arguments are also needed to qualify the property coefficients in various directions. The atomistic arguments are partly based on symmetry and party on the basic physics and chemistry of materials.
Download or read book Electroactive Polymer EAP Actuators as Artificial Muscles written by Yoseph Bar-Cohen and published by SPIE Press. This book was released on 2004 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the field of EAP with attention to all aspects and full infrastructure, including the available materials, analytical models, processing techniques, and characterization methods. This second edition covers advances in EAP in electric EAP, electroactive polymer gels, ionomeric polymer-metal composites, and carbon nanotube actuators.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ferroelectrics written by Mickaël Lallart and published by BoD – Books on Demand. This book was released on 2011-08-23 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ferroelectric materials have been and still are widely used in many applications, that have moved from sonar towards breakthrough technologies such as memories or optical devices. This book is a part of a four volume collection (covering material aspects, physical effects, characterization and modeling, and applications) and focuses on the application of ferroelectric devices to innovative systems. In particular, the use of these materials as varying capacitors, gyroscope, acoustics sensors and actuators, microgenerators and memory devices will be exposed, providing an up-to-date review of recent scientific findings and recent advances in the field of ferroelectric devices.
Download or read book Energy Materials Coordinating Committe EMaCC Fiscal Year 2002 Annual Technical Report written by and published by DIANE Publishing. This book was released on with total page 221 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 Bioinspired Actuators and Sensors written by Minoru Taya and published by Cambridge University Press. This book was released on 2016-10-13 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: From experts in engineering and biology, this is the first book to integrate sensor and actuator technology with bioinspired design.
Download or read book Ferroelectric Thin Films written by Masanori Okuyama and published by Springer Science & Business Media. This book was released on 2005-02-22 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ferroelectric thin films continue to attract much attention due to their developing applications in memory devices, FeRAM, infrared sensors, piezoelectric sensors and actuators. This book, aimed at students, researchers and developers, gives detailed information about the basic properties of these materials and the associated device physics. The contributing authors are acknowledged experts in the field.
Download or read book Polar Oxides written by Rainer Waser and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, more than 20 experts from leading research institutes around the world present the entire scope of this rapidly developing field. In so doing, they cover a wide range of topics, including the characterization and investigation of structural, dielectric and piezoelectric properties of ceramic materials, a well as phase transitions, electrical and optical properties and microscopic investigations. Another feature is a complete profile of the properties of polar oxides -- from their proof to their latest applications. Throughout, the authors review, discuss and assess the material properties with regard to new and advanced characterization and imaging techniques. For physicists, physicochemists, semiconductor and solid state physicists, materials scientists, and students of chemistry and physics.
Download or read book Mechanical Properties of Ceramics written by John B. Wachtman and published by John Wiley & Sons. This book was released on 2009-08-13 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Comprehensive and Self-Contained Treatment of the Theory and Practical Applications of Ceramic Materials When failure occurs in ceramic materials, it is often catastrophic, instantaneous, and total. Now in its Second Edition, this important book arms readers with a thorough and accurate understanding of the causes of these failures and how to design ceramics for failure avoidance. It systematically covers: Stress and strain Types of mechanical behavior Strength of defect-free solids Linear elastic fracture mechanics Measurements of elasticity, strength, and fracture toughness Subcritical crack propagation Toughening mechanisms in ceramics Effects of microstructure on toughness and strength Cyclic fatigue of ceramics Thermal stress and thermal shock in ceramics Fractography Dislocation and plastic deformation in ceramics Creep and superplasticity of ceramics Creep rupture at high temperatures and safe life design Hardness and wear And more While maintaining the first edition's reputation for being an indispensable professional resource, this new edition has been updated with sketches, explanations, figures, tables, summaries, and problem sets to make it more student-friendly as a textbook in undergraduate and graduate courses on the mechanical properties of ceramics.
Download or read book Domains in Ferroic Crystals and Thin Films written by Alexander Tagantsev and published by Springer Science & Business Media. This book was released on 2011-03-02 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: At present, the marketplace for professionals, researchers, and graduate students in solid-state physics and materials science lacks a book that presents a comprehensive discussion of ferroelectrics and related materials in a form that is suitable for experimentalists and engineers. This book proposes to present a wide coverage of domain-related issues concerning these materials. This coverage includes selected theoretical topics (which are covered in the existing literature) in addition to a plethora of experimental data which occupies over half of the book. The book presents experimental findings and theoretical understanding of ferroic (non-magnetic) domains developed during the past 60 years. It addresses the situation by looking specifically at bulk crystals and thin films, with a particular focus on recently-developed microelectronic applications and methods for observations of domains with techniques such as scanning force microscopy, polarized light microscopy, scanning optical microscopy, electron microscopy, and surface decorating techniques. "Domains in Ferroic Crystals and Thin Films" covers a large area of material properties and effects connected with static and dynamic properties of domains, which are extremely relevant to materials referred to as ferroics. In other textbooks on solid state physics, one large group of ferroics is customarily covered: those in which magnetic properties play a dominant role. Numerous books are specifically devoted to magnetic ferroics and cover a wide spectrum of magnetic domain phenomena. In contrast, "Domains in Ferroic Crystals and Thin Films" concentrates on domain-related phenomena in nonmagnetic ferroics. These materials are still inadequately represented in solid state physics textbooks and monographs.
