PVF2压电特性的研究

本文利用爆炸激波管研完了厚度为110μm的聚偏氟乙烯(PVF_2)在动载荷作用下的压电特性。采用石英传感器技术确定加载压力。研究表明,这种PVF_2具有压电特性强,重复性好的优点,它可以制成激波管实验研究所用的压力传感器。研究还表明,PVF_2的压电灵敏度与PVF_2的厚度近似成线性关系。     

高聚物压电膜的改进Mason分析模型

在压电方程中引入复数是弹系数，推导出考虑损耗的高聚物压是膜厚度振动模式改进Ｍａｓｏｎ模型。在传输线和受控源形式等效电路的基础上提出用ｎ级Ｔ型网络等效有损传输线，将其转化为适宜ＰＳＰＩＣＥ环境下实现的模型。将ＰＺＴ压电元件作为特例，并对ＰＶＤＦ－ＭＯＳＦＥＴ超声传感器采用本模型等铲电路用ＰＳＰＩＣＥ进行了模拟分析，得到与实验测量相一致的结果。     

聚偏二氟乙烯的压电性

本文阐述了聚偏二氟乙烯(PVDF)的物理特性,着重介绍了其压电性。PVDF是一种半晶状聚合物,它有四种不同的晶型。这些晶型可通过热、电场和压力作用而转变。     

PVDF@AgNWs复合压电发电机的制备与性能研究

采用静电纺丝法和退火后处理工艺制备高β相含量的聚偏氟乙烯(PVDF)纤维膜,并通过复合银纳米线(AgNWs)形成导电网络来获得高性能PVDF@AgNWs压电发电机。研究了制备工艺(静电纺丝、退火)及AgNWs添加量对器件压电输出性能的影响,结果表明,电纺PVDF纤维膜经退火并控制AgNWs质量分数0.10%条件下,PVDF@AgNWs压电发电机在5 MPa压力下,可输出约114 V压电电压及约1.3×10^-7 A电流。该压电发电机具有良好的能量采集性能,可直接为电容器充电,并可驱动LCD显示模组,在自供电柔性可穿戴电子领域具有应用潜力。     

PVDF压电纤维仿生柔性传感器水下传感特性研究

感知器官对于许多动物必不可少,尤其是生活在水下的生物。该文以聚偏二氟乙烯(PVDF)为材料,模仿水生动物海豹的触须设计制备了一种表面四电极PVDF压电纤维仿生柔性传感器。利用激振源测试所制备的传感器性能,包括输出不同的波形测试对不同激励的感知,对水动力的感知及对水下运动物体方向的感知。实验结果表明,该传感器对不同激励的感知性能很好,速度检测极限可达0.15 mm/s,且有良好的方向性检测能力,对水下情况感知的应用前景广。     

PVDF压电传感器的性能研究

分析了聚偏二氟乙烯（ＰＶＤＦ）制作的具有触觉、滑觉、温觉的仿生皮肤传感器的结构，研究其压电特性，建立仿生皮肤的分析模型。     

可穿戴式筒壳型压电能量收集器的研究与设计

针对可穿戴设备电源的供电及续航问题,采用了筒壳结构的压电能量收集器.探究了可穿戴筒壳结构压电能量收集器俘能的本质,并提出结构优化设计方案.首先指出筒壳结构的承载能力和初始能量与厚度成正比,且随着跨度的增大而减小;其次通过有限元仿真研究了基底和聚偏二氟乙烯(PVDF)压电薄膜尺寸与应力、应变的关系,指出PVDF的尺寸应尽...     

基于ZnO@rGO/PVDF柔性复合薄膜的压电纳米发电机

采用简单的一步水热法合成了自支撑的氧化锌纳米棒(ZnO NRs)@还原氧化石墨烯(rGO)复合材料,通过旋涂法制备ZnO@rGO/聚偏二氟乙烯(PVDF)柔性复合薄膜压电纳米发电机。研究结果表明,ZnO@rGO/PVDF柔性复合薄膜压电纳米发电机的输出性能随ZnO@rGO掺杂质量先增大后减小,当ZnO@rGO的质量分数为3.0%时,输出电压可达9.06 V,输出电流可达0.74μA,与仅掺杂3.0%ZnO NRs的ZnO/PVDF纳米发电机相比,其输出电压和电流分别提高了120%和124%。当负载电阻为10 MΩ时,ZnO@rGO/PVDF柔性复合薄膜压电纳米发电机输出功率最大为5.79μW。经过4 000次循环测试表明,该文所制备ZnO@rGO/PVDF柔性复合薄膜压电纳米发电机的输出性能稳定。该纳米发电机可以监测人体行走和跑步姿势,记录运动次数。有望作为自供电压力传感器件植入可穿戴电子设备中。     

基于PVDF压电传感器的微型扑翼机升力特性研究

采用一种新型方法测量微型扑翼机升力变化特性.在微型扑翼机机翼表面布置一矩形聚偏氟乙烯(PVDF)压电薄膜作为传感器,根据PVDF输出信号判断微型扑翼机对应的升力变化,与传统扑翼机升力变化特性实验研究相比,该方法具有简单、快捷、准确等优势.同时该文研究了微型扑翼飞行器在水平放置及迎风状态时的升力特性曲线,探讨了扑翼频率、飞行速度及扑翼的迎角对扑翼飞行升力的影响.     

基于压电薄膜传感器的软抓取机械手研究

基于压电效应和热电效应的新型薄膜传感器聚偏氟乙烯(PVDF)设计软抓取机械手,通过采集对抓取和释放过程中电荷量的变化判断抓取状态,利用模糊控制理论调控舵机实现软抓取功能。抓取质量小于1kg,体积小于10-3 m3的物体,平稳移动0.6m到达指定位置,偏移误差小于3cm;加入热觉感知功能,温度高于60℃时仿生机械手会自动弹开。基于压电薄膜传感器的软抓取机械手克服了传统机械手无法自主判断夹持力度的弊端,提高了仿生功能。     

Synthesis and characterization of porous polymeric low dielectric constant films

This paper reports the synthesis and dielectric properties of a porous poly(arylether) material with an ultra-low dielectric constant for interlayer dielectric applications in microelectronics. The porous polymer films were successfully fabricated by a method of organic phase separation and evaporation. A dielectric constant k of 1.8 was achieved for a porous film with an estimated porosity of 40% and average pore size of 3 nm. Electrical and mechanical properties as well as coefficient of thermal expansion for both dense and porous polymer films were measured.     

Sustainable Nanotextured Wave Energy Harvester Based on Ferroelectric Fatigue‐Free and Flexoelectricity‐Enhanced Piezoelectric P(VDF‐TrFE) Nanofibers with BaSrTiO3 Nanoparticles

Here, ultrathin, flexible, and sustainable nanofiber‐based piezoelectric nanogenerators (NF‐PENGs) are fabricated and applied as wave energy harvesters. The NF‐PENGs are composed of poly(vinylidene fluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)) nanofibers with embedded barium strontium titanate (BaSrTiO₃) nanoparticles, which are fabricated by using facile, scalable, and cost‐effective fiber‐forming methods, including electrospinning and solution blowing. The inclusion of ferroelectric BaSrTiO₃ nanoparticles inside the electrospun P(VDF‐TrFE) nanofibers enhances the sustainability of the NF‐PENGs and results in unique flexoelectricity‐enhanced piezoelectric nanofibers. Not only do these NF‐PENGs yield a superior performance compared to the previously reported NF‐PENGs, but they also exhibit an outstanding durability in terms of mechanical properties and cyclability. Furthermore, a new theoretical estimate of the energy harvesting efficiency from the water waves is introduced here, which can also be employed in future studies associated with various nanogenerators, including PENGs and triboelectric nanogenerators.     

准分子激光快速制备超疏水性聚偏氟乙烯材料

在室温条件下,利用KrF准分子激光辐照技术,实现了超疏水性聚偏氟乙烯高分子材料的快速制备,最快制备时间为10 s。实验结果表明,在改性后的材料表面上,与水静态接触角由原来的53°增加到170°左右。采用原子力显微镜和X射线光电子能谱等检测手段对辐照后的材料表面进行了微观形貌和化学结构分析,结果表明激光辐照区域产生了具有极规整三维网络结构的改性层,并且C-CF2和C-F两种化学基团取代了原有的化学结构CH2和CF2成为该改性层的主体。表面的粗糙化与低表面能化学基团的共同作用,使改性后的聚偏氟乙烯表面有效地产生了较强的超疏水性能。     

Transparent,Flexible, and Highly Sensitive Piezocomposite Capable of Harvesting and Monitoring Kinetic Movements of Microbubbles in Liquid

In this study, a zinc oxide (ZnO)-decorated nickel microfiber (ZNMF)-based piezoelectric nanogenerator (ZNMF-PENG) using electrospinning, metal electroplating, electrospraying, and ceramic growing techniques is fabricated. The combination of these techniques enables the ZNMF-PENG to possess high transparency and flexibility that are difficult to achieve through the existing piezoceramic-based PENGs. In particular, the presence of innumerable piezoceramic ZnO nanowires inside the ZNMF-PENG allows for detecting microbubble movements having an extremely low buoyancy force of 0.009 N, which is beneficial for detecting cavitation. Moreover, in comparison to previously reported PENGs fabricated using an electrospinning technique, the ZNMF-PENG demonstrates the highest energy-harvesting efficiency of 8750 V N⁻¹ m⁻². The novel approach in materials and methods proposed in this study is expected to contribute to the further advancement in developing transparent, flexible, and performance-improved PENGs applicable to various industrial applications.     

压电功能材料在结构主动减振降噪中的应用

利用压电材料的压电效应和逆压电效应.可分别实现压电传感器及压电致动器.采用压电传感器和致动器实现结构振动主动控制和噪声的有源控制是目前振动和噪声控制工程研究中的一个新领域.本文对此问题进行了分析,并指出了今后研究工作中应着重解决的问题.     

Recent Progress on Structure Manipulation of Poly(vinylidene fluoride)-Based Ferroelectric Polymers for Enhanced Piezoelectricity and Applications

Poly(vinylidene fluoride) (PVDF)-based polymers demonstrate great potential for applications in flexible and wearable electronics but show low piezoelectric coefficients (e.g., −d₃₃ < 30 pC N⁻¹). The effective improvement for the piezoelectricity of PVDF is achieved by manipulating its semicrystalline structures. However, there is still a debate about which component is the primary contributor to piezoelectricity. Therefore, current methods to improve the piezoelectricity of PVDF can be classified into modulations of the amorphous phase, the crystalline region, and the crystalline–amorphous interface. Here, the basic principles and measurements of piezoelectric coefficients for soft polymers are first discussed. Then, three different categories of structural modulations are reviewed. In each category, the physical understanding and strategies to improve the piezoelectric performance of PVDF are discussed. In particular, the crucial role of the oriented amorphous fraction at the crystalline–amorphous interface in determining the piezoelectricity of PVDF is emphasized. At last, the future development of high performance piezoelectric polymers is outlooked.     

CeO2 掺杂BNLKT陶瓷的压电性能与微观结构

利用企业的电子陶瓷工艺制备了CeO2掺杂Bi0.5(Na1-x-yLixKy)0.5TiO3无铅压电陶瓷,并研究了CeO2掺杂对该体系陶瓷的介电压电性能与微观结构的影响。X-射线衍射结果表明,掺杂的CeO2扩散进入了Bi0.5(Na1-x-yLixKy)0.5TiO3钙钛矿结构的晶格;SEM观察结果表明,少量的CeO2掺杂可改进该陶瓷的微结构;介电压电性能研究结果表明,CeO2掺杂对该陶瓷体系的综合性能有较大改善,室温下该体系配方的压电常数d33可达199 pC/N,径向机电耦合系数kp达39.3%,同时降低了陶瓷的介电损耗(tanδ=2.0%),提高了其机械品质因数。     

Surface Li2CO3 Mediated Phosphorization Enables Compatible Interfaces of Composite Polymer Electrolyte for Solid-State Lithium Batteries

Composite polymer electrolytes (CPEs) are subject to interface incompatibilities due to the space charge layer of ceramic and polymer phases. The intensive dehydrofluorination of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) incorporating Li₇La₃Zr₂O₁₂ (LLZO) significantly compromises electro-chemo-mechanical properties and compatibilities with electrodes. Herein, this study addresses the challenges by precisely phosphatizing LLZO surfaces through a surface Li₂CO₃ mediated chemical reaction. The designed neutral chemical environment of LLZO surfaces ensures high air stability and effective suppression of PVDF-HFP dehydrofluorination. This greatly facilitates the uniform distribution of ceramic and polymer phases, and fast interfacial Li⁺ exchange, establishing high-throughput ion percolation pathways and distinctly enhancing ionic conductivity and transference number. Moreover, the dramatically reduced formation of dehydrofluorination products and an in situ formed interphase layer between phosphatized surface and a Li metal anode stabilize the Li/CPE and cathode/CPE interfaces, which provide a symmetric Li/Li cell and solid-state Li/LiFePO₄ and Li/LiNi_0.8Co_0.1Mn_0.1O₂ cells an exceptional cycling performance at room temperature. This study emphasizes the vital importance of achieving electro-chemo-mechanical compatibilities for CPEs and provides a new waste to wealth route.