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Shengping Shen - One of the best experts on this subject based on the ideXlab platform.
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Decoupled shear Flexoelectric effects in polymers
Journal of Applied Physics, 2019Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Hui Ji, Shengping ShenAbstract:The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.
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Flexoelectret: An Electret with a Tunable Flexoelectriclike Response.
Physical Review Letters, 2019Co-Authors: Dongfan Li, Qian Deng, Shengping ShenAbstract:: Because of the Flexoelectric effect, dielectric materials usually polarize in response to a strain gradient. Soft materials are good candidates for developing a large strain gradient because of their good deformability. However, they always suffer from lower Flexoelectric Coefficients compared to ceramics. In this work, a Flexoelectriclike effect is introduced to enhance the effective Flexoelectricity of a polydimethylsiloxane bar. The Flexoelectriclike effect is realized by depositing a layer of net charges on the middle plane of the bar to form an electret. Experiments show that the enhancement of Flexoelectricity depends on the density of inserted net charges. It is found that a charged layer with surface potential of -5723 V results in a 100 times increase of the material's Flexoelectric Coefficient. We also show that the enhancement is proportional to the thickness of electrets. This work provides a new way of enhancing Flexoelectricity in soft materials and further prompts the application of soft materials in electromechanical transducers.
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Experimental decoupling of cylindrical Flexoelectric Coefficients
Applied Physics Letters, 2018Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential for the application of Flexoelectricity in irregular structures in complex environments.Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential f...
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Probing Flexoelectricity via a split Hopkinson pressure bar experiment
Applied Physics Letters, 2018Co-Authors: Taotao Hu, Qian Deng, Shengping ShenAbstract:Flexoelectricity is thought of as a universal property of all dielectric materials that couples polarization with the inhomogeneous deformation. However, at the macroscale, this coupling is usually very weak and the direct observation of Flexoelectricity always suffers from a low signal-to-noise ratio (SNR). At the micron or submicron scale, both the Flexoelectric effect and some surface effects may get pronounced simultaneously. To separate the Flexoelectric effect from those surface effects and accurately measure the bulk Flexoelectric Coefficients are challenging. In this paper, we propose a high SNR method for measuring the bulk Flexoelectric Coefficient μ 11 of millimeter-sized samples through split Hopkinson pressure bar (SHPB) experiments. Our experimental results show that for a normal impact speed (17 m/s) of the striker bar, the induced voltage difference is as high as 70 mV, which can be easily measured without using signal amplifiers. In most of previous works on measuring Flexoelectric Coefficients, strain gradients are introduced through the design of samples' shape such as thin beams, thin films, truncated cones and pyramids. In a different way, the proposed SHPB based approach introduces time varied strains to the system and then converts time gradients of strains into their spatial gradients through elastic waves. As a promising way of measuring bulk Flexoelectric Coefficients, this approach produces high SNR Flexoelectric signals, reduces interferences from surface effects, and avoids difficulties in fabricating nanostructures.Flexoelectricity is thought of as a universal property of all dielectric materials that couples polarization with the inhomogeneous deformation. However, at the macroscale, this coupling is usually very weak and the direct observation of Flexoelectricity always suffers from a low signal-to-noise ratio (SNR). At the micron or submicron scale, both the Flexoelectric effect and some surface effects may get pronounced simultaneously. To separate the Flexoelectric effect from those surface effects and accurately measure the bulk Flexoelectric Coefficients are challenging. In this paper, we propose a high SNR method for measuring the bulk Flexoelectric Coefficient μ 11 of millimeter-sized samples through split Hopkinson pressure bar (SHPB) experiments. Our experimental results show that for a normal impact speed (17 m/s) of the striker bar, the induced voltage difference is as high as 70 mV, which can be easily measured without using signal amplifiers. In most of previous works on measuring Flexoelectric c...
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Experimental approach for measuring cylindrical Flexoelectric Coefficients
Journal of Applied Physics, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of dielectric materials by which applied strain gradients induce electric polarizations within dielectric materials. Experimental research into the tensor components of the Flexoelectric Coefficient is essential. In this work, an experimental approach for measurement of the Flexoelectric Coefficient tensor components in cylindrical coordinates is developed. Two different experimental methods are designed to obtain the two related unknown Flexoelectric Coefficient tensor components. Theoretical and finite element analyses are developed and simplified for each experiment, and the related designs are then tested to obtain the coupled electric polarization charges. The two unknown Flexoelectric Coefficient tensor components of polyvinylidene fluoride are then decoupled. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components in solid dielectric materials.
Shuwen Zhang - One of the best experts on this subject based on the ideXlab platform.
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Decoupled shear Flexoelectric effects in polymers
Journal of Applied Physics, 2019Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Hui Ji, Shengping ShenAbstract:The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.
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Experimental decoupling of cylindrical Flexoelectric Coefficients
Applied Physics Letters, 2018Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential for the application of Flexoelectricity in irregular structures in complex environments.Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential f...
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Experimental approach for measuring cylindrical Flexoelectric Coefficients
Journal of Applied Physics, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of dielectric materials by which applied strain gradients induce electric polarizations within dielectric materials. Experimental research into the tensor components of the Flexoelectric Coefficient is essential. In this work, an experimental approach for measurement of the Flexoelectric Coefficient tensor components in cylindrical coordinates is developed. Two different experimental methods are designed to obtain the two related unknown Flexoelectric Coefficient tensor components. Theoretical and finite element analyses are developed and simplified for each experiment, and the related designs are then tested to obtain the coupled electric polarization charges. The two unknown Flexoelectric Coefficient tensor components of polyvinylidene fluoride are then decoupled. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components in solid dielectric materials.
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investigation of the 2312 Flexoelectric Coefficient component of polyvinylidene fluoride deduction simulation and mensuration
Scientific Reports, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Hao Shen, Kai Chen, Bo Feng, Shengping ShenAbstract:Flexoelectric effects hold promising applications in sensing, actuating, and energy capturing, and thus it is demanded to measure the Flexoelectric Coefficient tensors of dielectric materials accurately. In this work, an approach to measuring the effective Flexoelectric Coefficient tensor component μ 2312 of polymeric materials is developed by imposing a torque load upon a half cylindrical specimen. It is proven that μ 2312 can be calculated by assessing the electric charge on the axial plane and the strain gradient along the radial direction, both induced by the torque. To overcome the difficulty in experimental measurements, the relationship between the strain gradient and torque is deduced theoretically and further verified with finite element analysis. This approach is applied to testing bars machined from bulk polyvinylidene fluoride (PVDF). Potential errors from the piezoelectric effects and the non-uniform strain gradient are discussed to verify the validity of the measurement. The experimental results show good reproducibility and agreement with other measured effective Flexoelectric tensor components of PVDF. This work indicates a potential application of PVDF-based mechanical sensors and provides a method to investigate the effective Flexoelectric Coefficient component of polymers.
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the research of effective Flexoelectric Coefficient along 1123 direction in polyvinylidene fluoride
Journal of Applied Physics, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:All dielectric materials exhibit Flexoelectricity defined as a strain gradient-induced electric polarization. The Flexoelectric Coefficient measures electric polarization induced by strain gradient in dielectric materials. In this work, an approach to measure the 1123 component of the Flexoelectric Coefficient of polymeric materials is presented. Theoretical analysis and finite element analysis are performed on an un-polarized polyvinylidene fluoride rectangular beam. When deformation occurs in the specimen, a normal strain gradient is generated. The consistency of the elastic deformation determined through calculations and experimental measurements under applied loads was good. The experimental system was set up as follows: a circular sine wave load with bias value was applied to the specimen and the strain gradient-induced electric charge curve was measured. The Flexoelectric Coefficient μ1123 was obtained and was consistent with our theoretical calculations of the electric polarization induced by the s...
Minglong Xu - One of the best experts on this subject based on the ideXlab platform.
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Decoupled shear Flexoelectric effects in polymers
Journal of Applied Physics, 2019Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Hui Ji, Shengping ShenAbstract:The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.The coupling between dielectric polarization and strain gradient, known as Flexoelectricity, is a property of all dielectric materials. Flexoelectric Coefficients are essential during applications. In order to increase the number of measurable Flexoelectric Coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the Flexoelectric Coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the Flexoelectric Coefficients μφzρz and μφzzz are simultaneously obtained. This Flexoelectric Coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear Flexoelectric effects.
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Experimental decoupling of cylindrical Flexoelectric Coefficients
Applied Physics Letters, 2018Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential for the application of Flexoelectricity in irregular structures in complex environments.Flexoelectricity is a property of all dielectric materials in which they polarize in response to deformation gradients such as those produced by pressing, bending, or twisting, and knowledge of Flexoelectric Coefficients is essential when considering the applications of Flexoelectricity. Here, we describe an experimental approach to the measurement of cylindrical Flexoelectric Coefficients of polyvinylidene fluoride. Two specimens are designed to generate and decouple the corresponding strain gradients. Theoretical and finite element analyses are developed and simplified, and specimen designs are then tested to obtain multiple strain-gradient-coupled electric polarization charges. The Flexoelectric Coefficients μφzρρ and μφzzρ are then decoupled, using two independent equations together with the experimental data. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components by imposition of a twisting load, and it reveals the potential f...
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Experimental approach for measuring cylindrical Flexoelectric Coefficients
Journal of Applied Physics, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:Flexoelectricity is a property of dielectric materials by which applied strain gradients induce electric polarizations within dielectric materials. Experimental research into the tensor components of the Flexoelectric Coefficient is essential. In this work, an experimental approach for measurement of the Flexoelectric Coefficient tensor components in cylindrical coordinates is developed. Two different experimental methods are designed to obtain the two related unknown Flexoelectric Coefficient tensor components. Theoretical and finite element analyses are developed and simplified for each experiment, and the related designs are then tested to obtain the coupled electric polarization charges. The two unknown Flexoelectric Coefficient tensor components of polyvinylidene fluoride are then decoupled. This work provides an experimental method that can be used to obtain multiple unknown Flexoelectric Coefficient tensor components in solid dielectric materials.
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investigation of the 2312 Flexoelectric Coefficient component of polyvinylidene fluoride deduction simulation and mensuration
Scientific Reports, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Hao Shen, Kai Chen, Bo Feng, Shengping ShenAbstract:Flexoelectric effects hold promising applications in sensing, actuating, and energy capturing, and thus it is demanded to measure the Flexoelectric Coefficient tensors of dielectric materials accurately. In this work, an approach to measuring the effective Flexoelectric Coefficient tensor component μ 2312 of polymeric materials is developed by imposing a torque load upon a half cylindrical specimen. It is proven that μ 2312 can be calculated by assessing the electric charge on the axial plane and the strain gradient along the radial direction, both induced by the torque. To overcome the difficulty in experimental measurements, the relationship between the strain gradient and torque is deduced theoretically and further verified with finite element analysis. This approach is applied to testing bars machined from bulk polyvinylidene fluoride (PVDF). Potential errors from the piezoelectric effects and the non-uniform strain gradient are discussed to verify the validity of the measurement. The experimental results show good reproducibility and agreement with other measured effective Flexoelectric tensor components of PVDF. This work indicates a potential application of PVDF-based mechanical sensors and provides a method to investigate the effective Flexoelectric Coefficient component of polymers.
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the research of effective Flexoelectric Coefficient along 1123 direction in polyvinylidene fluoride
Journal of Applied Physics, 2017Co-Authors: Shuwen Zhang, Minglong Xu, Tonghui Wu, Shengping ShenAbstract:All dielectric materials exhibit Flexoelectricity defined as a strain gradient-induced electric polarization. The Flexoelectric Coefficient measures electric polarization induced by strain gradient in dielectric materials. In this work, an approach to measure the 1123 component of the Flexoelectric Coefficient of polymeric materials is presented. Theoretical analysis and finite element analysis are performed on an un-polarized polyvinylidene fluoride rectangular beam. When deformation occurs in the specimen, a normal strain gradient is generated. The consistency of the elastic deformation determined through calculations and experimental measurements under applied loads was good. The experimental system was set up as follows: a circular sine wave load with bias value was applied to the specimen and the strain gradient-induced electric charge curve was measured. The Flexoelectric Coefficient μ1123 was obtained and was consistent with our theoretical calculations of the electric polarization induced by the s...
Xu Liang - One of the best experts on this subject based on the ideXlab platform.
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measuring the Flexoelectric Coefficient of bulk barium titanate from a shock wave experiment
Journal of Applied Physics, 2017Co-Authors: Taotao Hu, Xu Liang, Qian Deng, Shengping ShenAbstract:In this paper, a phenomenon of polarization introduced by shock waves is experimentally studied. Although this phenomenon has been reported previously in the community of physics, this is the first time to link it to Flexoelectricity, the coupling between electric polarization and strain gradients in dielectrics. As the shock waves propagate in a dielectric material, electric polarization is thought to be induced by the strain gradient at the shock front. First, we control the first-order hydrogen gas gun to impact and generate shock waves in unpolarized bulk barium titanate (BT) samples. Then, a high-precision oscilloscope is used to measure the voltage generated by the Flexoelectric effect. Based on experimental results, strain elastic wave theory, and Flexoelectric theory, a longitudinal Flexoelectric Coefficient of the bulk BT sample is calculated to be μ 11 = 17.33 × 10 − 6 C/m, which is in accord with the published transverse Flexoelectric Coefficient. This method effectively suppresses the majority...
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Experimental method research on transverse Flexoelectric response of poly(vinylidene fluoride)
Japanese Journal of Applied Physics, 2016Co-Authors: Shuwen Zhang, Minglong Xu, Xu Liang, Guoliang Ma, Shengping ShenAbstract:Flexoelectricity describes the strain-gradient-induced electric polarization existing in dielectric materials. The Coefficient that exists between the strain-gradient and the induced electric polarization defines the Flexoelectric Coefficient tensor. It is necessary to analyze different experimental methods to evaluate the procedure of measuring the transverse Flexoelectric Coefficient tensor component. In this work, the transverse Flexoelectric Coefficient tensor component of poly(vinylidene fluoride) (PVDF) is studied using three different experimental methods and the effects of the mentioned methods are evaluated. The results presented in this work are helpful for the design of experiments of different dielectric materials, including ceramics and polymers on Flexoelectricity.
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improved approach to measure the direct Flexoelectric Coefficient of bulk polyvinylidene fluoride
Journal of Applied Physics, 2016Co-Authors: Jianfeng Lu, Minglong Xu, Xu Liang, Jiangyan Lv, Shengping ShenAbstract:We experimentally studied the built-in polarization induced effective piezoelectric constant and direct Flexoelectric Coefficient in α-phase bulk polyvinylidene fluoride (PVDF). This phenomenon was detected and discussed based on the compression of a truncated cone. An improved mechanical formulation of Flexoelectricity was presented and discussed in this study, and the experiment was carried out based on the charge measurement. From the experiment study, a Flexoelectric coupling Coefficient 202.3 V was calculated from the Flexoelectric Coefficient μ11=1.6×10−8C/m for bulk polyvinylidene fluoride. We measured the Flexoelectric response of bulk PVDF with consideration of the residual piezoelectric contributions and geometry-dependent calibration, which affect the Flexoelectric measurement.We experimentally studied the built-in polarization induced effective piezoelectric constant and direct Flexoelectric Coefficient in α-phase bulk polyvinylidene fluoride (PVDF). This phenomenon was detected and discussed based on the compression of a truncated cone. An improved mechanical formulation of Flexoelectricity was presented and discussed in this study, and the experiment was carried out based on the charge measurement. From the experiment study, a Flexoelectric coupling Coefficient 202.3 V was calculated from the Flexoelectric Coefficient μ11=1.6×10−8C/m for bulk polyvinylidene fluoride. We measured the Flexoelectric response of bulk PVDF with consideration of the residual piezoelectric contributions and geometry-dependent calibration, which affect the Flexoelectric measurement.
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Shear Flexoelectric response along 3121 direction in polyvinylidene fluoride
Applied Physics Letters, 2015Co-Authors: Shuwen Zhang, Minglong Xu, Xu Liang, Bo Feng, Shengping ShenAbstract:Flexoelectricity describes the strain gradient-induced electric polarization. Due to the restrictions of experiment technologies, some of the components of Flexoelectric Coefficient have not been experimentally obtained. In this letter, an experimental method for the measurement of the shear Flexoelectric response along 3121 direction of polyvinylidene fluoride (PVDF) is presented. An experiment is conducted on various unpolarized specimens, where shear strain gradient is generated along the radial direction by applying torque to 3 specially designed specimens. The generated shear strain gradient is calculated via finite element analysis and the corresponding induced electrical response is measured. Dynamic torque is exerted on the specimens with a static bias value and at different frequencies. The shear Flexoelectric Coefficient μ3121 is found to have an average value of 1.037 × 10−8 C/m. With this method, the shear Flexoelectric response along 3121 direction of PVDF is experimentally obtained. The expe...
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shear Flexoelectric Coefficient μ1211 in polyvinylidene fluoride
Journal of Applied Physics, 2015Co-Authors: Shuwen Zhang, Minglong Xu, Xu Liang, Shengping ShenAbstract:Defined as a strain gradient-induced electric polarization, Flexoelectricity exists in all dielectric materials. The Coefficient that exists between the strain gradient and the electric polarization defines the Flexoelectric Coefficient tensor. The tensor components along the longitudinal and transverse directions have been studied widely. However, little progress has been reported on Flexoelectric properties in the shear direction to date. In this work, a novel method for measurement of the shear Flexoelectric Coefficient μ1211 of polyvinylidene fluoride is presented. An experiment is conducted on a tubular unpolarized specimen, where shear strain gradient is generated along the radial direction by applying torque to the ends of the tube-shaped specimen. Dynamic torque is exerted on specimens with a static bias value and at different frequencies. The generated shear strain gradient is calculated via finite element analysis and the corresponding induced electrical polarization is measured using a charge a...
Xiaoning Jiang - One of the best experts on this subject based on the ideXlab platform.
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Giant Flexoelectricity in Ba0.6Sr0.4TiO3/Ni0.8Zn0.2Fe2O4 composite
Applied Physics Letters, 2014Co-Authors: Yong Li, Wenbin Huang, Xiaoning Jiang, Hong WangAbstract:Enhanced Flexoelectricity in perovskite ceramics and single crystals has been reported before. In this letter, 3-3 ceramic-ceramic Ba0.6Sr0.4TiO3/Ni0.8Zn0.2Fe2O4 composite with a colossal permittivity was employed in the conventional pure bending experiment in order to examine the transverse Flexoelectric response. The measured Flexoelectric Coefficient at 30 Hz is 128 μC/m and varies to 16 μC/m with the frequency increasing from 30 Hz to 120 Hz, mainly due to the inverse correlation between the permittivity and the frequency. This result reveals the permittivity dependence of Flexoelectric Coefficient in the frequency dispersion materials, suggesting that the giant permittivity composites can be good Flexoelectric materials.
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Flexoelectricity in barium strontium titanate thin film
Applied Physics Letters, 2014Co-Authors: Seol Ryung Kwon, Wenbin Huang, Fuh-gwo Yuan, Jon-paul Maria, Xiaoning JiangAbstract:Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop Flexoelectric devices on micro/nano scales due to the inherent scaling effect of Flexoelectric effect. Ba0.7Sr0.3TiO3 thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The Flexoelectric Coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse Flexoelectric Coefficient of 24.5 μC/m at Curie temperature (∼28 °C) and 17.44 μC/m at 41 °C. The measured Flexoelectric Coefficients are comparable to that of bulk BST ceramics, which are reported to be 10–100 μC/m. This result suggests that the Flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.
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converse Flexoelectric Coefficient f1212 in bulk ba0 67sr0 33tio3
Applied Physics Letters, 2014Co-Authors: Wenbin Huang, Seol Ryung Kwon, Zhao Wang, Fei Li, Shujun Zhang, Michael T Lanagan, Xiaoning JiangAbstract:The converse Flexoelectric effect, referred as the electric field gradient induced strain, widely exists in dielectric materials, but its experimental studies have been reported by few research groups so far. In this Letter, we report our studies on the converse Flexoelectric behavior of (Ba0.67Sr0.33)TiO3 ceramics and present the measured value of its Flexoelectric Coefficient f1212. In the experiments, the electric field gradient was generated by applying an electric field across the two lateral sides of trapezoid (Ba0.67Sr0.33)TiO3 samples. The shear displacement was measured using a laser vibrometer. The converse Flexoelectric Coefficient f1212 was found to be 124 ± 14 μC/m at room temperature. This result was in good agreement with the theoretical prediction of the Flexoelectricity of the (Ba, Sr)TiO3 ceramics.