Download or read book Development of the Piezoelectric Properties of Poly vinylidene Fluoride Based Ferroelectrics and Ferroelectrets Using Fillers and Mechanical Stretching written by Nusrat Jahan and published by . This book was released on 2018 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric polymers are very useful in various electromechanical applications because of their strong piezoelectric response, flexibility, lightweight and formability. In addition to ferroelectric ceramics, ferroelectric polymers (such as PVDF) and ferroelectrets are also popular as a new group of piezoelectrics. Ferroelectrics based on b-PVDF are interesting due to the ease of preparation with usable piezoelectric response in addition to the above mentioned advantages of polymers. Incorporating nanofillers (e.g. ceramic filler-BaTiO3, PZT, carbon nanotube, clay, ferrite nanoparticles etc.) into PVDF is one of the facile ways to produce b phase in PVDF often followed by mechanical stretching. While fillers nucleate b phase in the PVDF matrix, subsequent mechanical stretching helps in aligning the dipoles to some extent. Therefore, the aim of the first part of this study is to prepare ferroelectric b-PVDF films by incorporating a hybrid filler (micro-CaCO3+ nanoclay) followed by mechanical stretching. While nanoclay is one of the most widely used cost-effective fillers capable of nucleating b-PVDF, synergistic improvement in b phase formation as well as in mechanical, electrical and piezoelectric properties of hybrid composites have been reported in this part of the study. Additionally, the influence of subsequent mechanical stretching e.g. draw ratio, R (final length/initial length), has also been investigated. FTIR and XRD are employed to determine the b phase content in both stretched and unstretched samples. While the tensile properties show a gradual decrease, dielectric constant increased gradually with increasing CaCO3 content in the hybrid filler. The maximum piezoelectric d33 coefficient of 30 pC/N is obtained for stretched hybrid composite films. Ferroelectrets, on the other hand, are another type of functional polymer films with heterogeneous cellular structure and internal quasi-permanent dipole moments. The piezoelectricity in ferroelectrets originates from the change in dipole moments under an applied mechanical stress. Over the past few decades, cellular polypropylene (PP) films have been the most popular and widely investigated ferroelectrets and are already in commercial applications. While the piezoelectric d33 coefficient of PP ferroelectrets could exhibit up to 1000 pC/N or more, their working temperature is quite low, not higher than 60 °C. Recently developed fluoropolymer i.e. polytetrafluoroethylene (PTFE) and fluoroethylene propylene (FEP) based ferroelectrets exhibit strong piezoelectric response and excellent thermal stability. However, processing these fluoropolymer ferroelectrets using commercially viable manufacturing technique such as cast film extrusion poses few challenges because of their very high melt viscosity, high manufacturing temperature, degradation tendency and low tensile elongation. Therefore, in this part of the study, a new thermally stable ferroelectret has been investigated using commercial processing technique with strong piezoelectric response. Cast extrusion of the polymer/filler mixture followed by mechanical stretching is one of the promising techniques for preparing a cellular polymer. Micron scale fillers are usually employed for creating voids from interfacial delamination under applied stress. Polyvinylidene fluoride (PVDF) is a fluoropolymer which is easily melt-processable than other fluoropolymers and showing excellent physical, chemical and electrical properties. An "extrusion-stretching-inflation" process has been followed to prepare a cellular structure in PVDF films. Solid PVDF/hybrid filler (micro-CaCO3 + nanoclay) films were extruded and subsequently stretched to create the initial cellular structure inside the films. While CaCO3 acts as void nucleation centers, nanoclay increases the stretchability of the highly CaCO3 filled PVDF films. Gas diffusion expansion (GDE) or controlled inflation is preformed to adjust the voids dimensions to lens-shaped voids leading to lower elastic moduli and stronger piezoelectricity. Obviously, the gas permeation characteristics in polar polymers is different than non-polar polymers because of their different type of polymer/gas interaction and the final piezoelectric properties of the ferroelectrets strongly depend on the cellular morphology such as void size, shape and distribution. Therefore, two different inflation gases i.e. neutral N2 and polar CO2 are used with various inflation strategies. Combination of pressure, temperature and their way of application (direct or step-wise) is examined for various times to optimize the inflation level. The inflated films are then subjected to corona charging at room temperature to create the dipoles inside the voids. Finally, PVDF ferroelectrets show piezoelectric d33 coefficient as high as 251 pC/N with N2 inflation and 327 pC/N for CO2 treatment. As expected, PVDF ferroelectrets exhibit better thermal stability than PP, PETP, COP and PEN and as high as Teflon. Samples charged at room temperature have their working temperature up to 120 °C

Download or read book Preparation and Investigation of Polymer Foam Films and Polymer Layer Systems for Ferroelectrets written by Peng Fang and published by . This book was released on 2010 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Applications of Ferroelectric Polymers written by T. T. Wang and published by . This book was released on 1988 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 913 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 Modeling of Structural Elastic and Polar Properties of Organic and Inorganic Ferroelectrics written by Fu-Chang Sun and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational materials science has become an important branch of research with the advent of high performance computers and efficient algorithms. The viability of solving fundamental theories allows not only to understand experimental results, but predict properties of exotic materials or materials at extreme conditions. There exists fundamental theories that has been applied in different domains of length and time scales, where certain approximations are employed which enable improved performance with minimum compromise of accuracy. In this Thesis, various computational approaches at different length scales are considered to investigate different classes of organic and inorganic ferroelectric materials to describe structural-property relations. The in-plane and out-of-plane piezoelectric properties of (001) strontium titanate (SrTiO$_3$, STO) epitaxial thin films on pseudo-cubic (001) substrates are computed as a function of in-plane misfit strain. A nonlinear thermodynamic model is employed, which takes into account the appropriate mechanical boundary conditions, the electromechanical coupling between the polarization and the in-plane lattice mismatch, and the self-strains of the ferroelastic and ferroelectric phase transformations. The piezoelectric behavior of epitaxial STO films is described in various strain-induced ferroelectric phase fields in a temperature range from $-$50 to 50 $\degree$C. These results indicate that strain engineered STO films may be employed in a variety of sensor and actuator applications as well as surface acoustic wave devices and thin-film bulk acoustic resonators. Implementing the same technique, piezoelectric properties of epitaxial (001) barium strontium titanate (BST) films are computed as functions of composition, misfit strain, and temperature using a non-linear thermodynamic model. Results show that through adjusting in-plane strains, a highly adaptive rhombohedral ferroelectric phase can be stabilized at room temperature with outstanding piezoelectric response exceeding those of lead based piezoceramics. Furthermore, by adjusting the composition and the in-plane misfit, an electrically tunable piezoelectric response can be obtained in the paraelectric state. These findings indicate that strain engineered BST films can be utilized in the development of electrically tunable and switchable surface and bulk acoustic wave resonators. The theoretical model of ferroelectric bilayers using basic thermodynamics taking into account the appropriate electrical boundary conditions and electrostatic fields is present. We show that ferroelectric multilayers are not simple capacitors in series (CIS) and treating these as CIS may lead to misinterpretation of experimental results and to erroneous conclusions. The spontaneous polarization mismatch in ferroelectric/ferroelectric (FE/FE), FE/paraelectric (FE/PE), and FE/dielectric (FE/DE) bilayers results in a non-linear electrostatic coupling which produces significant deviations in the overall dielectric response if it is computed using the simple capacitor-in-series (CIS) model. Our results show that the CIS approach is a good approximation only for DE/DE multilayers and for FE heterostructures if the individual layers are electrostatically screened from each other. As a second method for this Thesis, classical molecular dynamics computations are considered to calculate the structural, elastic, and polar properties of crystalline ferroelectric $\beta$ phase poly(vinylidene fluoride), PVDF, with randomized trifluoroethylene TrFE as a function of TrFE content. The results show that molecular dynamics can be used to predict the mechanical and polarization-related behavior of ferroelectric poly(VDF\textit{-co-}TrFE). The same computational approach might be also utilized for other polymeric materials in the desired temperature and/or composition range. Furthermore, temperature-induced and deformation-induced phase transitions are reported, which are consistent with the experimental observation. Finally, the fundamental theory of electron physics, also called the first-principles formalism, is applied to study the polarization of the layered ferroelectric bismuth titanate (BiT). The electronic structure studies of pure BiT and technologically significant lanthanum-doped bismuth titanate (La-doped BiT) are performed. The results and the extension of current progress of A-site substitutional BiT using first-principle calculations could provide the theoretical evidence of the formation of oxygen vacancies, which is recognized to be associated with the leakage current and polarization properties. Studies on the optical properties of BiT are performed using a beyond-density functional theory (beyond-DFT) method. This is done because the regular approximation for electron-electron coupling in the DFT specific generalized gradient approximation (GGA) has limitations in predicting the band gap of semiconductors/insulators. The Heyd-Scuseria-Ernzerhof (HSE) screened hybrid-functional method is adopted.

Download or read book The Dynamic Mechanical Piezoelectric and Dielectric Properties of Poly vinylidene Fluoride written by Alan Rushworth and published by . This book was released on 1977 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electromechanical Properties in Composites Based on Ferroelectrics written by Vitaly Yuryevich Topolov and published by Springer Science & Business Media. This book was released on 2008-10-20 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Electromechanical Properties in Composites Based on Ferroelectrics” investigates the problem of prediction and non-monotonicity of the effective electromechanical (piezoelectric, dielectric and elastic) properties in two- and three-component composites based on ferroelectric ceramics and relaxor-ferroelectric single crystals. The book analyzes the interrelations between the electromechanical constants of the components, and describes the different analytical schemes for averaging the properties of these materials with different connectivity and microgeometrical characteristics. The book highlights the advantages of different methods for predicting the electromechanical properties and choosing the optimum components, and demonstrates the non-trivial behavior of specific composite architectures and the parameters of value for engineering applications. The book is of benefit to all specialists looking to understand the detailed behavior and electromechanical response of advanced composite materials.

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 Ferroelectric and Piezoelectric Properties of a Quenched Poly Vinylidene Fluoride Trifluoroethylene Copolymer written by and published by . This book was released on 1996 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ferroelectric and piezoelectric properties of melt-quenched unoriented poly(vinylidene fluoride-trifluoroethylene) (73:27) copolymer films as a function of the number of poling cycles have been studied. The investigation revealed that quenched films exhibit a decrease in D-E hysteresis behavior as the number of poling cycles increases when the samples are poled at room temperature. Corresponding decreases in remanent polarization, Pr, as well as small increases in the coercive field, Ec, were observed as the material was subjected to successive poling cycles. The piezoelectric coefficients, d31 and e31, also decreased as the number of poling cycles increased. In addition, a clear reduction in the 'apparent' Curie transition temperature between unpoled and poled material was observed. Preliminary evidence indicates that films quenched below Tc do not form a stable ferroelectric crystal phase as previously believed.

Download or read book Ferroelectric Polymers written by E. Fukada and published by CRC Press. This book was released on 1989 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains four papers commencing with an introduction to early studies in piezoelectricity, pyroelectricity and ferroelectricity in polymers. Other topics discussed include - ferroelectric properties of fluoride copolymers; structural phase transition in ferroelectric fluorine polymers; and pressure effect on phase transition in ferroelectric polymers .

Download or read book Advanced Ferroelectric And Piezoelectric Materials With Improved Properties And Their Applications written by Ivan A Parinov and published by World Scientific. This book was released on 2024-03-14 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover the latest advances in ferroelectric and piezoelectric material sciences with this comprehensive monograph, divided into six chapters, each offering unique insights into the field.Chapter 1 delves into the manufacture and study of new ceramic materials, focusing on complex oxides of various metals (Aurivillius phases). The authors explore layered bismuth titanates and niobates, known for their high Curie temperature, and discuss how varying their chemical composition can lead to significant changes in their electrophysical properties. Chapter 2 explores the fascinating world of ferroelectrics — dielectrics with spontaneous polarization. Mathematical models and approaches of fractional calculus are used to understand the process of polarization switching in these materials, shedding light on the fractality of electrical responses. In Chapter 3, readers gain valuable insights into the inhomogeneous polarization process of polycrystalline ferroelectrics, a crucial stage in creating piezoceramic samples for energy converters. The authors present a comprehensive mathematical model that allows the determination of various characteristics, including dielectric and piezoelectric hysteresis loops and the effect of attenuation processes.Chapter 4 focuses on state-of-the-art piezoelectric energy harvesting, discussing theoretical, experimental, and computer modelling approaches. The authors discuss piezoelectric generators (PEGs) of different types (cantilever, stack and axis) and nonlinear effects arising at their operation. Chapter 5 presents expanded test and finite element models for cantilever-type and axial-type PEGs with active elements. The studies cover various structural and electric schemes of the PEGs with proof mass, bimorph and cylindrical piezoelectric elements, and excitation loads. Finally, Chapter 6 reviews some results in the last five years, obtained in modelling the vibration of devices from piezoactive materials, including five important effects: piezoelectric, flexoelectric, pyroelectric, piezomagnetic and flexomagnetic.As a diverse addition to the literature, this book is a relevant resource for researchers, engineers, and students seeking to expand their knowledge of cutting-edge developments in this exciting field.

Download or read book Medical Applications Of Piezoelectric Polymers written by Pierre M. Galletti and published by Gordon & Breach Science Pub. This book was released on 1988 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive book presents a detailed account of the operating principles of piezoelectric polymer transducers and their promising application in the field of biomedical research instrumentation. It emphasizes the novel measurement opportunities offered by the pliable and tissue-matches properties of the polymer transducer material.

Download or read book PVDF Based Ferroelectric Polymers written by and published by de Gruyter. This book was released on 2017-05-23 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book begins by introducing signals and systems, and then discusses Time-Domain analysis and Frequency-Domain analysis for Continuous-Time systems. It also covers Z-transform, state-space analysis and system synthesis. The author provides abundant examples and exercises to facilitate learning, preparing students for subsequent courses on circuit analysis and communication theory.

Download or read book Ferroelectric and Piezoelectric Properties of Nylon 11 Poly Vinylidene Fluoride Bilaminate Films written by and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ferroelectric and piezoelectric properties of a new class of polymer ferroelectric and piezoelectric materials, nylon 11/polyvinyi lidene fluoride (PVF2) bilaminate films, prepared by a co-melt-pressing method, is presented. The bilaminate films exhibit typical ferroelectric D-E hysteresis behavior with a remanent polarization, P(sub r), of about 75 mC/sq m, which is higher than the value of 52 mC/sq m observed for PVF2 or nylon 11 films measured under the same conditions. The coercive field, E(sub c), of the bilaminate films is approx. 78 Mv/m which is higher than that of either PVF2 or nylon 11 films. Measurements of the temperature dependence of the piezoelectric strain coefficient, d31, and the piezoelectric stress coefficient, e31, were also carried out. The bilaminate films exhibit a piezoelectric strain coefficient, d31, of 41 pC/N at room temperature, which is significantly higher than the PVF2 films (25 pC/N) and the nylon 11 films (3.1 pC/N). jg.

Download or read book Confined Ferroelectric Properties in Poly vinylidene Fluoride PVDF based Random Copolymers and Graft Copolymers for Electric Energy Storage Applications written by Fangxiao Guan and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation on Ferroelectric and Flexoelectric Properties of Poly vinylidenefluoride hexafluoropropylene PVDF HFP Copolymer Films written by Ho Joon Lee and published by . This book was released on 2010 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electric polarization induced by the non-uniform deformation, i.e. the direct flexoelectric effect, in poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) has been investigated. The ferroelectric properties of PVDF-HFP copolymer films were measured. The primary goal of the research in this thesis is to understand the properties of both ferroelectricity and flexoelectricity of PVDF-HFP copolymer films under different circumstances. It is well known that PVDF homo polymer mainly has three phase structures, α phase (TGTG'), β phase (TTTT), and γ phase (TTTGTTTG'), depending on the chain conformations as the trans (T) or the gauche (G) linkages. Only β phase and γ phase possess piezoelectric responses. The direct flexoelectric effect can exist in any phase. This is because the inhomogeneous deformation can break the inversion symmetry and induce electric polarization even in non-piezoelectric crystalline materials.^However, in PVDF-HFP copolymer, the molecular chain conformations of PVDF are modified by HFP monomers. Although the mixture of two polymers can be regarded as a random amorphous structure, their molecular chain conformations may splay to different directions if a non-uniform deformation is applied to them. Therefore both ferroelectric and flexoelectric properties of PVDF-HFP copolymers might be significantly different from that of PVDF homo polymers. In our experimental studies, the unaligned PVDF-HFP copolymer films were initially synthesized by using the solution polymerization process and then characterized via X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The flexoelectric coefficients of those polymer films were then measured. Both the enhanced direct flexoelectric effect and the ferroelectric-like behavior were observed in the polymer films.^However, the flexoelectric coefficient of PVDF-HFP copolymers we measured is almost 50% smaller than that of the unaligned PVDF homo films. The experimental results also demonstrate that the ferroelectric-like behavior in PVDF-HFP copolymers under different conditions might be induced by their spatially distributed space electric charges. The measured flexoelectric coefficient (μ13) and the piezoelectric coefficient (d13) can also give us valuable information about the property degradation, or aging phenomena, in polymer films and the related polymer devices.

Download or read book Flexoelectric and Ferroelectric Properties of Quenched Polyvinylidene Fluoride PVDF Homopolymer Films written by Sankar Thiruvannamalai and published by . This book was released on 2010 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: The flexoelectric and ferroelectric properties of quenched polyvinylidene fluoride (PVDF) homopolymer films have been investigated in this thesis. It is well known that PVDF homopolymer mainly has three phase structures, alpha phase (TGTG'), beta phase (TTTT), and gamma phase (TTTGTTTG'), depending on the chain conformations as the trans (T) or the gauche (G) linkages. However, the quenched PVDF homopolymer has different molecular chain conformations, which may render some unique mechanical and electric properties. Quenching is a mechanical process in which PVDF homopolymer is strengthened and hardened. This is done by heating PVDF solution at a certain temperature, where the polymerization cannot be formed, then rapidly cooling the polymer; in annealing process, only in certain local microscopic areas, polymerization can occur to let PVDF monomer molecules aggregate together to form the alpha, beta, and gamma phases.^So the regions between those areas in the polymer have amorphous structures. Thus, the piezoelectric behavior of the quenched PVDF homopolymer might be altered since only beta phase and gamma phase in PVDF possess piezoelectric responses and the volume, in which both beta phase and gamma phase exist, in the quenched polymer is reduced. However, whether the direct flexoelectric effect is influenced or not in the quenched PVDF homopolymer is still unknown. This is because the direct flexoelectric effect can exist in polymers of any phase; the inhomogeneous deformation can break the inversion symmetry and induce electric polarization even in non-piezoelectric phase. In our experimental studies, the quenched PVDF homopolymer films were initially synthesized using solution polymerization process and then were quenched in ice-water. We further characterized our samples by using X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM).^The flexoelectric coefficients of those polymer films were then measured. Both the enhanced direct flexoelectric effect and the ferroelectric-like behavior were observed in the quenched polymer films. Our studies have shown that both the effect and the behavior largely depend on the molecular chain configurations of the quenched PVDF films. Our experimental results also demonstrate that the ferroelectric-like behavior in the quenched PVDF film might be induced by its spatially distributed space electric charges. The measured flexoelectric coefficient (mu13) may also give us valuable information about how aging phenomena would be induced in polymer films.