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Describes the deformation of 1-3 type piezoelectric composite materials under different conditions. Use of piezocomposites; Application of the force equilibrium condition; Comparison between the strain profile of the polymer phase in the 2-2 composite with the 1-3 composite.

Presents a theoretical study on the static performance of piezoelectric ceramic-polymer composites with 1-3 connectivity. Displacement profiles in a single-rod composite under uniaxial and hydrostatic stresses; Aspect ratio of the ceramic rods for 1-3 structures; Calculation of the hydrostatic piezoelectric constant for the single-rod 1-3 composite.

Analyzes plane wave propagation at the composite-medium interface for the piezoceramic polymer composites with laminated periodic structure. Description of the composite structure; Solution to the field equations in the fluid region in the case of the fluid composite interface; Relationship used to evaluate the input acoustic impedance of a composite at the interface.

Presents a dynamic theory on the piezoceramic polymer composite with 2-2 connectivity. Description and illustration of the composite; Governing equations for the problem using the coordinate system of the composite; Benefits of the theory presented.

By combining the high-dielectric copper phthalocyanine oligomer (PolyCuPc) and conductive polyanline (PANI) within polyurethane (PU) matrix an all-organic three-component dielectric-percolative composite with high dielectric constant is demonstrated. In this three-component composite system, the high-dielectric-constant PolyCuPc particulates enhance the dielectric constant of the PU matrix and this combined two-component dielectric matrix in turn serves as the high-dielectric-constant host for the PANI to realize percolative phenomenon and further enhance the dielectric response. As a result, an electromechanical strain of 9.3% and elastic energy density of 0.4 J/cm3 under an electric field of 20 V/μm can be induced. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The apparent molecular density of states from combined photoemission and inverse photoemission spectroscopies is compared to the bulk conductivity and frequency dependent dielectric measurements for a variety of ferroelectric polymer poly(vinylidene fluoride) (PVDF) copolymers and terpolymers. While some extra chemical groups introduced into the PVDF long chains increase the measured conductivities at room temperature and can cause significant changes in the dielectric properties, few changes are observed in the overall experimental molecular density of states. The exception appears to be the very short polymer chains. The significance of this comparison is that profound changes can occur in the overall dielectric and transport properties of this class of polymers and copolymers through molecular “dopant addition,” without altering the overall density of states of the dominant PVDF polymer host. [ABSTRACT FROM AUTHOR]

We investigate the influence of the composition, especially the chlorofluoroethylene content, on the ferroelectric and electromechanical properties of the poly(vinylidene fluoride-trifluoroethylene- chlorofluoroethylene) (PVDF-TrFE-CFE). It was found that increasing the CFE from 0 to 9 mol % gradually converts the normal ferroelectric of the copolymer (in the compositions range of VDF/TrFE mole ratio between 64/36 to 75/25) to a relaxor ferroelectric, resulting in a nearly hysteresis free polarization loop and high electrostrictive response. On the other hand, increasing CFE content causes reduction in crystallinity, which will affect the elastic modulus and the induced polarization level of the polymer. These competing effects determine the desired terpolymer compositions for given applications. The electromechanical strain as a function of induced polarization and macropolar phase fraction was modeled by a modified electrostrictive relation, which closely matches experimental data. It is found that the electrostrictive coefficient is relatively constant across the compositions investigated. [ABSTRACT FROM AUTHOR]

This paper presents a hierarchically designed polymer nanocomposite approach in which nanofillers at ultralow volume loading generate large dielectric enhancement in blends of high temperature dielectric polymers with tailored nanostructures. We blend poly(1,4-phenylenen ether sulfone) (PES) with polymers, such as polyetherimide (PEI), that possess more coiled chain conformations to tailor polymer nano-morphologies. Making use of such blends as the matrix, dilute nanocomposites with 0.65 vol. % loading of alumina nanoparticles (20 nm size) generate a marked enhancement in dielectric performance, i.e., raising the dielectric constant K from PES K = 3.9 (and PEI K = 3.2) to the dilute nanocomposites K = 7.6, a much higher enhancement compared with the dilute nanocomposites employing neat polymers as the matrix. The results show that polymer blends with tailored nano-morphologies as the matrix can lead to higher dielectric enhancement in dilute nanocomposites compared with neat polymers as the matrix. [ABSTRACT FROM AUTHOR]

Ferroelectric materials are intrinsically multifunctional and have found a broad range of applications. A new class of semicrystalline terpolymers comprising vinylidene fluoride (VDF), trifluoroethylene (TrFE), and 1, 1-chlorofluoroethylene (CFE), were prepared at Institut de Saint-Louis (ISL) via a suspension polymerization process. Relevant studies and results show that this class of electroactive polymers offers unique properties in comparison with other ferroelectric polymers. The terpolymer exhibits high electrostrictive strain (x>7%) with relatively high modulus (>0.3GPa). It has been also observed that the large electrostrictive strain is nearly constant in the temperature range from 20 to 80 °C. The high room temperature relative dielectric constant (∼ 50), which is the highest among all the known polymers), high induced polarization (∼ 0.05 C/m²), and high electric breakdown field (>400 MV/m) lead to very high volume efficiency for the electric energy storage operated under high voltage (∼ 10 J/cm³). [ABSTRACT FROM AUTHOR]

High energy density polymer materials are desirable for a broad range of modern power electronic systems. Here, we report the development of a new class of polymer dielectrics based on polyurea and polythiourea, which possess high thermal stability. By increasing the dipole density, the dielectric constant of meta-phenylene polyurea and methylene polythiourea can be increased to 5.7, compared with aromatic polyurea and aromatic polythiourea, which have a dielectric constant in the range of 4.1-4.3. The random dipoles with high dipolar moment and amorphous structure of these polyurea and polythiourea based polymers provide strong scattering to the charge carriers, resulting in low losses even at high electric fields. Consequently, this new class of polymers exhibit a linear dielectric response to the highest field measured (>700 MV/m) with a high breakdown strength, achieving high energy density (>13 J/cm3) with high efficiency (>90%). [ABSTRACT FROM AUTHOR]

Electrically induced behavior was investigated and compared in the non-stretched and uniaxially stretched poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene), P(VDF-TrFE-CFE) terpolymer-a member of the P(VDF-TrFE)-based relaxor polymers family that exhibits fast response speeds, giant electrostriction, high electric energy density, and large electrocaloric effect. Although the temperature dependence of the low-field complex dielectric constant is almost identical in the non-stretched and stretched samples, the dc bias electric field via higher nonlinear contribution more heavily alters the dielectric response of the non-stretched terpolymer. The polarization response and, particularly, the induced electrostrictive strain are, on the other hand, much higher in the more-oriented stretched films. The changes in polar-correlation range induced by film stretching also strongly influence the directly measured electrocaloric response, which shows more pronounced temperature dependence in the stretched terpolymer. These results suggest that electrically induced properties of relaxor polymer films can be tailored by controlling the preparation conditions. [ABSTRACT FROM AUTHOR]

Ferroelectric relaxor poly(vinylidene fluoride-trifluoroethylene-1,1-chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer with VDF/TrFE/CFE composition of 59.2/34.6/7.2 (mole %) exhibits a high dielectric constant (∼50) around room temperature and strong electromechanical response. It can form miscible blends with poly(methyl methacrylate) (PMMA). This paper reports the results of a systematic investigation of the influence of PMMA on the microstructure and electromechanical responses of the terpolymer blends with PMMA content up to 10 wt %. It was found that the crystallinity of the blends decreases nearly linearly with increased PMMA content. Since the dielectric constant and polarization response of P(VDF-TrFE-CFE) terpolymer are mainly from the crystalline region, these properties accordingly exhibit proportional reduction with increased PMMA concentration. Nevertheless, a small amount (∼5 wt %, for instance) of PMMA can raise the elastic modulus of the blend quite markedly while the field-induced strain level is not affected very much. Consequently, the elastic energy density can be enhanced in the blends. As a result, the electromechanical efficiency of blends in the composition range investigated is also significantly improved. In addition, the mechanical loss factor is dramatically decreased at room temperature by blending with PMMA. [ABSTRACT FROM AUTHOR]

Ferroelectric relaxor P(VDF-TrFE-CFE) terpolymer can generate a hysteresis-free polarization of 47 mC/m2 at an electric field of 100 MV/m and is attractive for many potential actuating and sensing applications. Fourier transform infrared spectra under electric field reveal that this large polarization originates from the field-induced crystalline phase transformation. The nonpolar TGTG′ chain conformation in P(VDF-TrFE-CFE) can be converted into polar trans (Tm>4 and T3G) conformation under high electric field and the latter can be effectively aligned to the applied field direction. Furthermore, this conformation transformation is completely reversible and no hysteresis can be observed during the switching of applied electric field. In contrast, normal ferroelectric polymer P(VDF-TrFE) exhibits square polarization loop with very small reversible polarization. [ABSTRACT FROM AUTHOR]

We report the directly measured electrocaloric effect (ECE) (the adiabatic temperature change ΔT) of relaxor ferroelectric poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer and its blend with poly(vinylidene fluoride-chlorotrifluoroethylene). The results show that the directly measured ΔT in the relaxor terpolymer is much larger than that deduced from Maxwell relation and that the relaxor terpolymer possesses a giant ECE at room temperature. The large difference between the directly measured ΔT and that deduced indicates that the Maxwell relation, which is derived for ergodic systems, is not suitable for deducing ECE in the relaxor ferroelectric polymers, which are nonergodic (polar-glass) material systems. [ABSTRACT FROM AUTHOR]

We introduce a stencil mask method to fabricate metallic patch arrays on the electrostrictive poly(vinylidene fluoride–trifluoroethylene) copolymer films. The resulting frequency selective surfaces exhibit resonance responses in the infrared region. Furthermore, the resonant frequency can be tuned by the strain change in the copolymer films. The results demonstrate that the stencil mask method is useful for depositing metallic patterns on a subset of substrates such as polymers that would be damaged by solvents used in conventional photolithography techniques. [ABSTRACT FROM AUTHOR]

We report on the performance of micromachined unimorph actuators [(polymer micromachined actuator PMAT)] based on the electrostrictive poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] copolymer. Because of the high electrostrictive strain and high elastic energy density (∼1 J/cm[sup 3]) of the active polymer [the electrostrictive P(VDF–TrFE)], the PMAT exhibits a very high stroke level with high load capability and high displacement voltage ratio. In addition, the experimental data also demonstrate that the PMAT is capable of operating over a broad frequency range (>100 kHz). The PMAT performance was modeled and the agreement between the modeling results and experimental data confirms that the response of the PMAT indeed follows the design parameters. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The recent finding of large electrocaloric effect in several ferroelectric polymers creates unique opportunity for developing compact size solid state cooling cycles beyond the traditional mechanical vapor compression cycles. Here, we show that, by employing regeneration process with solid state regenerators, a chip scale Electrocaloric Oscillatory Refrigeration (ECOR) can be realized. A prototype ECOR is fabricated and characterized. More than 6 K temperature span is obtained near room temperature between the hot and cold sides of a 2 cm long device. Finite volume simulation validates the test results and shows the potential high performance of the ECOR. [ABSTRACT FROM AUTHOR]

The electrocaloric (EC) effect attracted attention due to recent predictions of the existence of a giant EC in polymeric and inorganic ferroelectric materials based on indirect measurements of the electric polarization. The giant EC effect could potentially be of great importance in development of cooling or heating devices of new generation, which would be more environmentally friendly. A method and analysis of direct measurements of the giant EC effect in P(VDF-TrFE) (68/32 mol%) copolymer thin films are presented. It is found that the EC effect is of similar magnitude as found in P(VDF-TrFE) (55/45 mol%) copolymer by indirect method. [ABSTRACT FROM AUTHOR]

The giant electrocaloric (EC) effect is of great importance for application in cooling or heating devices of new generation, which would be friendlier for environment. Recent predictions of the existence of the giant EC effect in polymeric and inorganic ferroelectric relaxors are based solely on the indirect measurements of the electric polarization and not on a direct measurement of the EC effect itself. Here a method and analysis of direct measurements of the giant EC effect in various soft and solid ferroelectric materials in the form of thick and thin films is presented. The field dependence of the EC effect is shown for PbMg1/3Nb2/3O3 (PMN) ceramics and P(VDF-TrFE) (68/32 mol%) copolymers. [ABSTRACT FROM AUTHOR]

We investigate nonlinear conduction in aromatic polyurea thin films and its influence on the dielectric applications over a broad temperature range. The experimental data indicate that several high field conduction mechanisms coexist in the polymer films and one conduction mechanism may dominate over the others depending on different temperatures. The results also reveal that owing to the non-linear increase of the conduction loss with field, the dielectric loss at high field can be many orders of magnitude larger than that at low field. Therefore, besides the electrical breakdown strength, the conduction loss at high field and their temperature dependence behavior are other key factors in developing polymer dielectric materials for high energy density dielectric applications over a broad temperature range. [ABSTRACT FROM AUTHOR]

We present recent studies in the fundamentals and applications of the relaxor ferroelectric polymers, i.e., Poly(vinylidene fluoride-trifluroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE) terpolymers and high energy electron irradiated P(VDF-TrFE) copolymers. We show that the dynamic processes in these relaxor ferroelectric polymers are very similar to these observed in various polar-glasses. We further show that the large and reversible polarization change in these polymers leads to giant electrostriction and large electro-optic effect. By employing active electric boundary conditions, we demonstrate that the large electromechanical responses in these electroactive polymers can be made use of effectively for energy harvesting with high harvested electric energy density and efficiency. Terpolymer composites with ZnS nanoparticles provide an advanced E-O polymer which refractive index can be varied widely by small amount of ZnS in the composites while maintaining the large E-O effect of the matrix. [ABSTRACT FROM AUTHOR]

The relaxor ferroelectric polymer, based on poly(vinylidene fluoride-trifluoroethylene- chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer, exhibits high electromechanical response and dielectric response, suitable for a wide range of army applications such as micro-actuators, high efficiency pulse power capacitors, and solid state cooling devices. Recent experimental results show that with a simple blends approach, the terpolymer glass transition temperature can be raised quite markedly, resulting in a significant increase in the elastic modulus and consequently the elastic energy density, while the polarization response and electrostrictive strain remaining nearly the same. Utilizing the high electromechanical response, thin film microactuators and micropumps were fabricated, which showed very high microactuator displacement and force capability in comparison with the traditional piezoceramic based microdevices. Ink-jet microprinting technique was investigated for the fabrication of thin film devices and with a proper control of the solution conditions and surface chemistry, thin films with feature size down to less than 30 μ m can be fabricated. [ABSTRACT FROM AUTHOR]

This paper investigates the relaxor ferroelectric polymer—poly(vinylidene fluoride/trifluoroethylene/chlorofluoroethylene) terpolymer for energy storage capacitors. It is found that the high dielectric constant (> 50 at 1 kHz) and high reversible polarization in the terpolymer lead to a high electric energy density ∼ 10 J/cm³, achieved under an electric field of more than 350 MV/m. The high dielectric constant also causes the polarization saturation at fields much below the breakdown field and whereby the discharged energy density increases nearly linearly with applied field, distinctively different from the low dielectric constant linear dielectric polymers whose energy density rises with square of the applied field. The strong frequency dispersion and nonlinear polarization response (polarization saturation) of the relaxor terpolymer result in a low effective capacitance at the beginning of the discharge and the effective capacitance increases with time during the discharge. Furthermore, due to the frequency dispersion and nonlinear effect, the discharged energy density of the terpolymer to a resistor load RL increases with RL. A large RL will lead to high discharge efficiency in the terpolymer capacitor. [ABSTRACT FROM AUTHOR]

The relaxor ferroelectric polymers, i.e., the poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] based terpolymers and high energy electron irradiated copolymers, provide unique opportunity to investigate the ferroelectric relaxor behavior in polymeric materials. Experimental evidence shows that there is fundamental difference in the microstructures between the relaxor terpolymer and relaxor irradiated copolymer even though both exhibit similar macroscopic ferroelectric relaxor response. [ABSTRACT FROM AUTHOR]

The dielectric response of an all-organic composite, comprising copper-phthalocyanine (CuPc) oligomers dispersed in the P(VDF-TrFE-CFE) terpolymer, was studied and compared to data obtained in the terpolymer and in oligomers. Although admixture of CuPc strongly increases the dielectric constant of the terpolymer at all temperatures, each of the two constituents governs the dielectric dynamics of the composite in a different temperature region--the relaxorlike matrix above and semiconducting CuPc below the terpolymer's freezing temperature. Results on ac-conductivity reveal that polaron tunneling is one of the dominating charge transport mechanisms as in CuPc oligomers as well as in the CuPc-P(VDF-TrFE-CFE) composite. [ABSTRACT FROM AUTHOR]

Besides the high electrostriction in the relaxor P(VDF-TrFE-CFE) terpolymers, the high dielectric constant (> 50) and high breakdown field lead to a high electric energy density (∼10 J/cm³), which is attractive for the high efficiency charge storage capacitors. This paper presents charging and discharging behavior, as well as the discharged energy density as a function of the field. The field dependence of the polarization response and the polarization saturation at very high field result in a nearly linear increase of the discharged energy density with field. For the field dependent polarization response in the low to medium field range, Rayleigh's law has been introduced in the past to describe the field dependent behavior (with loss) in this field range. We examine the relationship between the Rayleigh's law and the complex dielectric constant notation used widely in the scientific and engineering community and show that a modified complex notation can describe the field dependent dielectric response with loss in the low and medium field range quite well. [ABSTRACT FROM AUTHOR]

A magnetoelectric (ME) composite through thermal mediation is presented, which is different from the traditional strain/stress mediated ME composites. The ME laminate uses the large magnetocaloric effect, that is, a temperature change induced in the ferromagnetic Gd crystal by a magnetic field, and a large pyroelectric response in the relaxor ferroelectric polymer. Consequently, a simple laminate composite can produce a ME response ∼0.5 V/(cm Oe). The ME coefficient was further enhanced to ∼0.9 V/(cm Oe) by exploiting the magnetic flux concentration effect. The approach opens up an avenue in developing ME materials for broad range of applications. [ABSTRACT FROM AUTHOR]

We investigate the electromechanical response of conductor network composite (CNC) fabricated by the layer-by-layer (LbL) self-assembly method. The process makes it possible for CNCs to be fabricated at submicron thickness with high precision and quality. This CNCs exhibits high strain ∼6.8% under 4 V, whereas the RuO2/Nafion CNCs exhibit strain ∼3.3%. The high strain and submicron thickness of the LbL layers in an ionic polymer metal composite (IPMC) yield large and fast actuation. The response time of a 26 μm thick IPMC with 0.4 μm thick LbL CNCs to step voltage of 4 V is 0.18 s. [ABSTRACT FROM AUTHOR]

The evolution of relaxor ferroelectric behavior of poly(vinylidene fluoride trifluoroethylene chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer nanorods with diameters reduced from 200 to 25 nm was investigated. It was observed that all the nanorods studied exhibited relaxor ferroelectric behavior, as characterized by the dielectric peak shifting toward high temperatures with increasing frequency. The frequency-permittivity peak temperature characteristics fit well with the Vogel–Fulcher (VF) relation. Moreover, the freezing temperature in the VF relation decreased with the reduction of nanorod diameter, indicating that the scaling down of the lateral size of nanorods influenced the relaxor ferroelectric behavior of the terpolymer. [ABSTRACT FROM AUTHOR]

This paper investigates the electrical breakdown of a polar fluoropolymer, poly(vinylidene fluoride-hexafluoropropylene) which exhibits an exceptionally high discharged electrical energy density (>25 J/cm3). It is shown that above room temperature, the breakdown strength decreases with temperature. It is further shown that such a temperature dependence of breakdown strength is consistent with the electromechanical breakdown model by taking into consideration of the plastic deformation of semicrystalline polymers. [ABSTRACT FROM AUTHOR]

This paper investigates dielectric properties of the blends of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer and poly(vinylidene fluoride-chlorotrifluoroethylene) copolymer. The high field (>50 MV/m) polarization response of the blends with a small amount of copolymer (5 and 10 wt % copolymer) is higher than that of the neat terpolymer due to the interface contribution. At the same time the breakdown field was also greatly improved by mixing a small amount of the copolymer with the terpolymer. Consequently, a higher energy density of about 11.5 J/cm3 is obtained in these blends in contrast to about 9 J/cm3 in the terpolymer. [ABSTRACT FROM AUTHOR]

Applying an electrical field to a polar polymer may induce a large change in the dipolar ordering, and if the associated entropy changes are large, they can be explored in cooling applications. With the use of the Maxwell relation between the pyroelectric coefficient and the electrocaloric effect (ECE), it was determined that a large ECE can be realized in the ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer at temperatures above the ferroetectric-paraelectric transition (above 70°C), where an isothermal entropy change of more than 55 joules per kilogram per kelvin degree and adiabatic temperature change of more than 12°C were observed. We further showed that a similar level of ECE near room temperature can be achieved by working with the relaxor ferroelectric polymer of P(VDF-TrFE-chlorofluoroethylene). [ABSTRACT FROM AUTHOR]

We report a class of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymers synthesized via reductive dechlorination from P(VDF-CTFE) [termed as the reduced P(VDF-TrFE) copolymer], which exhibit ferroelectric relaxor behavior at high temperature (∼100 °C). It was found that the reduced P(VDF-TrFE) 66/34 mol % copolymer has very high content of head-to-head and tail-to-tail defects, which may act as random defects, leading to the observed ferroelectric relaxor at high temperature. Furthermore, the reduced copolymer also exhibits a high melting point (∼200 °C), which also makes it attractive for high-temperature dielectric applications. [ABSTRACT FROM AUTHOR]

We investigate the energy harvesting with an electrostrictive polymer, possessing high electromechanical response and elastic energy density, which make it possible to generate high electric energy density and attractive for the active energy harvesting scheme. It is shown that combining the active energy harvesting scheme and high electromechanical response of the polymer yields a harvested electric energy density of ∼40 mJ/cm3 with a 10% efficiency. [ABSTRACT FROM AUTHOR]

The authors show that a high transverse piezoelectric response with both high piezoelectric d31 (d31=43.1 pm/V) and electromechanical coupling k31 coefficients (k31=0.187), much higher than those in the piezoelectric poly(vinylidene fluoride) and poly(vinylidene fluoride-trifluoroethylene) copolymers, can be obtained in poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] 10 wt % copolymers under quasistatic condition. Furthermore, the copolymers also display a higher d31 coefficient compared to the d33 coefficient, which seems to be unusual compared with most other piezopolymers. The experimental data suggest that the origin of the unusual piezoelectric response in these P(VDF-HFP) copolymers originates from a reversible change between a poled α-like structure and β-like structure. The phase change nature also results in a large frequency dispersion of the piezoelectric response and a smaller d31 (=20.5 pm/V) at 50 kHz. [ABSTRACT FROM AUTHOR]

Dielectric polymers with high dipole density have the potential to achieve very high energy density, which is required in many modern electronics and electric systems. We demonstrate that a very high energy density with fast discharge speed and low loss can be obtained in defect-modified poly(vinylidene fluoride) polymers. This is achieved by combining nonpolar and polar molecular structural changes of the polymer with the proper dielectric constants, to avoid the electric displacement saturation at electric fields well below the breakdown field. The results indicate that a very high dielectric constant may not be desirable to reach a very high energy density. [ABSTRACT FROM AUTHOR]

On page 1300, by modifying BaTiO3 ceramics to their invariant critical points, Ba(ZrxTi1−x)O3 bulk ceramics exhibit a large electrocaloric effect (ECE). Q. M. Zhang and co‐workers show tetragonal, orthorhombic, and rhombohedral structures behind a larger cubic structure, with dipoles inside. A flat‐panel cooling device is schematically drawn as a 3D multi‐layered ECE cooling device. The temperature gradient is shown by rainbow color, in which blue indicates the cold end and the other warmer colors indicate higher temperatures. [ABSTRACT FROM AUTHOR]

A correction to the article "Large electric tunability in poly(vinylidene fluoride-trifluoroethylene) based polymers," by S. G. Lu, B. Neese, B. J. Chu, Y. Wang, and Q. M. Zhang is presented.

Provides a corrected reprint of the article 'Ferroelectric and Electromechanical Properties of Poly(Vinylidene-Fluoride-Trifluoroethylene-Chlorotrifluoroethylene) terpolymer,' by Haisheng Xu, Z.-Y. Cheng, Dana Olson, T. Mai, Q.M. Zhang and G. Kavarnos, currently published in 2001 issue of 'Applied Physics Letters' journal.