纺丝电压对静电纺PVDF纤维膜压电效应的影响

纺丝电压是影响静电纺聚偏氟乙烯(PVDF)纤维膜β相生成和压电效应的重要因素之一。目前不同文献中对电压影响的研究结果存在不同观点。采用静电纺丝方法,在不同电压(14.0~24.0 k V)条件下制备了PVDF纤维膜,测试了不同电压下PVDF纤维膜的压电响应,利用FTIR和XRD方法表征了不同电压下PVDF纤维膜的β相含量。结果表明,在给定的纺丝电压范围内,PVDF纤维膜的压电响应输出和β相含量均存在最大值。通过对比分析其他研究结果,对影响试验结果的因素展开了讨论。     

SiO2原位掺杂聚偏氟乙烯纳米纤维膜的制备及其性能

为提高聚偏氟乙烯(PVDF)的压电性能,以PVDF和正硅酸乙酯(TEOS)为原料,N,N-二甲基甲酰胺(DMF)和丙酮为混合溶剂,利用原位复合溶胶-凝胶法和高压静电纺丝技术制备纳米SiO₂原位掺杂PVDF复合纳米纤维膜,并分析纳米纤维膜的表面微观形貌、化学结构、力学性能以及压电性能等。结果表明:复合纳米纤维膜的面密度与厚度随TEOS质量的增加而增加;静电纺丝使PVDF中部分α相转变为β相,纯PVDF纳米纤维膜的β相含量是PVDF粉末的1.54倍,为(31.42±0.62)%;且原位掺杂SiO₂后β相含量进一步提高,拉伸强力与输出电压均呈先增大后降低的趋势,当TEOS质量为1.643 g时PVDF纳米纤维膜β相含量最高为(42.59±0.62)%,原位掺杂PVDF纳米纤维膜拉伸强力最大为(8.03±0.19) N,输出电压最高为(2.33±0.13) V。     

碳纳米管/聚偏氟乙烯纳米纤维膜的制备及其压电性能

为提高聚偏氟乙烯(PVDF)的压电性能,采用静电纺丝法将碳纳米管(CNTs)引入到PVDF纳米纤维膜中制备CNTs/PVDF纳米纤维膜,并组装成三明治结构的柔性压电传感器,探究CNTs质量分数对CNTs/PVDF纳米纤维膜压电性能的影响。借助扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、万能试验机以及数字示波器对纳米纤维的形貌、结构、力学性能及压电性能进行表征。结果表明:CNTs/PVDF纳米纤维膜具有良好的力学特性,CNTs的添加有利于晶体结构中β晶型的形成;当CNTs质量分数为5%时,CNTs/PVDF纳米纤维的晶体结构中β晶型含量最多,压电性能最强,此时柔性传感器的输出电压达到最大值7.5 V。     

载药聚偏氟乙烯伤口敷料的制备及其性能

为获得轻薄柔软的伤口敷料,并使其具备优异的压电和抗菌性能,以聚偏氟乙烯(PVDF)为原料,掺杂不同质量分数的盐酸恩诺沙星(Enro),采用静电纺丝技术制备载药PVDF复合纳米纤维膜。分析了复合纳米纤维膜的形貌、化学结构对其压电性能、药物缓释和抗菌性能的影响。结果表明:PVDF质量分数为8%时,纤维平均直径为(753±128) nm,纤维网成膜良好,复合纳米纤维膜直径随着Enro质量分数的增加呈先增大后减小趋势;纺丝过程中PVDF由α晶型转变为β晶型,使纤维膜具备了压电性能,可产生9 mV的输出电压;当 Enro质量分数为15%时,纤维膜释药速度平稳、持续时间长且具备优异的抗菌性能,适合用作伤口敷料。     

聚偏氟乙烯/FeCl3复合纤维膜柔性传感器的制备及其性能

为制备灵敏度高的柔性传感器,将六水合三氯化铁(FeCl₃·6H₂O)加入聚偏氟乙烯(PVDF)中,采用静电纺丝法制备PVDF/FeCl₃复合纤维膜并组装成传感器。借助扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、接触角分析仪等对纤维膜的形貌、结构、润湿性、力学性能及压电性能进行表征。结果表明:适量的FeCl₃·6H₂O 添加可增加纤维膜中β晶型的相对含量,进而有效提高传感器的压电输出性能,但过多FeCl₃·6H₂O会抑制β晶型的形成;当FeCl₃·6H₂O质量分数为0.5%时,纤维晶体结构中β晶型的比例达到最大值68.74%,最高输出电压达到约5 V;传感器对激振过程的反应时间可达0.025 s,且在不同激振频率下的响应时间基本一致,动态高频时具有较高的压电输出。     

静电纺钛酸钡/聚偏氟乙烯纳米复合柔性压电纤维膜

为进一步提高聚偏氟乙烯（PVDF）压电性能,采用具有铁电性能的钛酸钡(BaTiO3)纳米颗粒为无机填料,通过静电纺丝技术制备BaTiO3/PVDF纳米复合纤维膜。借助扫描电子显微镜、全反射红外光谱、差示扫描量热法、X射线衍射以及脉冲电压测试等仪器对纤维膜的结构和性能进行了表征及分析,探索了不同添加量的BaTiO3对复合纤维膜结晶结构及压电性能的影响。结果表明：静电纺丝过程中静电力的拉伸和纳米BaTiO3的成核作用促进了PVDF具有压电性的β晶型的形成;当BaTiO3质量分数为10%,复合纤维膜的β晶型含量达到90.8%,纤维膜的输出电压值由20 V增加至50 V;制得的BaTiO3/PVDF复合纤维薄膜具有良好的压电性。     

高压电性静电纺柔性氧化锌/聚偏氟乙烯复合纤维膜

为了获得环保、柔软、透气和高压电性的材料,增加压电材料在纳米发电机,传感器,可穿戴电子器件等方面的应用,采用静电纺丝技术制备出了高压电性的氧化锌/聚偏氟乙烯（ZnO/PVDF）复合纤维膜材料。通过扫描电子显微镜、全反射傅里叶变换红外光谱仪、X射线衍射仪及示波器对压电复合纤维膜的形貌、结构和压电性进行了表征。结果表明：在PVDF基材中加入适量的氧化锌纳米颗粒(ZnO NPs)可在一定程度上提升PVDF纤维膜的结晶度和电活性β晶型含量增加,使PVDF中总的β晶型含量增加;同时,ZnO NPs自身具有压电性,也可进一步提升复合材料的压电性,使复合纤维膜的输出电压显著提高。当ZnO NPs质量分数为30%时,复合膜的输出电压高达60V,与纯PVDF纤维膜的输出电压相比,复合纤维膜的压电性提升了200%。     

静电纺制备PVDF纳米纤维膜的应用

聚偏氟乙烯(PVDF)是一种新型高分子材料,通过静电纺丝法制备的PVDF纳米纤维膜具有压电系数高、生物相容性好、质轻柔软等优点,近年来在各领域得到广泛应用。为了充分认识PVDF纤维膜,简要对比了溶液流延法、静电纺丝法制作PVDF纤维膜的优缺点,详细介绍了溶液静电纺丝法制备聚偏氟乙烯纳米纤维膜的工艺过程。重点分析了当前PVDF纳米纤维膜在压电传感器、生物医学、过滤材料、电池隔膜等领域的应用现状。探索了在生产和应用领域上存在的问题,并提出了PVDF纳米纤维膜的发展前景。     

聚丙烯腈/硝酸钠纳米纤维膜的制备及其压电性能

为提高聚丙烯腈(PAN)纤维膜的压电性能,将硝酸钠(NaNO₃)掺杂到PAN中,利用静电纺丝技术制备了PAN/NaNO₃纳米纤维膜。探究了NaNO₃用量以及纺丝速度对静电纺PAN纤维膜压电性能的影响。通过扫描电子显微镜、红外光谱仪、X射线衍射仪、驻极体非织造压电性能测试系统以及压电测试仪对PAN/NaNO₃纤维膜的表面形貌、构象和压电性能进行表征与测试。结果表明:将NaNO₃掺杂到PAN中会导致纤维膜的平面锯齿构象含量增加,晶面间距减小,进而影响PAN纤维膜的压电性能;当NaNO₃质量分数为0.9%、纺丝速度为1 000 mm/s时,纤维膜的压电性能明显提高,此时PAN/NaNO₃纤维膜中平面锯齿构象含量最多,晶面间距最小,与未掺杂NaNO₃的PAN纤维膜相比,此PAN纤维膜压电电压和电流分别提高了40%和174.53%。     

基于静电纺丝的柔性各向异性应变传感器的制备及其性能

为实现特定方向应变的检测,拓展柔性应变传感器的适用范围,利用磁场辅助静电纺丝技术制备平行排布的聚偏氟乙烯(PVDF)纳米纤维薄膜,并组装成各向异性柔性压电传感器。探究了纺丝参数对纤维薄膜形貌的影响,借助拉曼光谱仪对其化学结构进行表征;对传感器的应变响应性进行测试,并验证其应用于输尿管蠕动检测的可行性。结果表明:纺丝电压为11.5 kV,纺丝距离为13 cm,推注速率为5 mL/h条件下制备的PVDF纳米纤维具有均一的形貌和取向性,且纳米纤维膜为β晶型结构;柔性各向异性应变传感器对于沿PVDF纳米纤维垂直方向的应变,能够产生显著的电压响应信号,而对沿PVDF纳米纤维平行方向的应变不敏感,显示出良好的各向异性应变检测能力。     

Modeling of electrospun PVDF/LiCl nanogenerator by the energy approach method: determining piezoelectric constant

Increasing demands for harvesting energy from other sources of energy than fossil fuel and oil have led to an upsurge of interest in nano-structured materials such as piezoelectric nanofibers and nanowebs to harvest energy from environmental movements. Previous research introduced a suitable nanogenerator package to have higher output voltage needless of the post-treatment process. Electrospinning of PVDF (polyvinylidene fluoride) with LiCl (lithium chloride) increases the beta-crystalline phase and thus piezoelectric effect. This article presents an FEM (finite element method) model for the electrospun PVDF/LiCl nanogenerator to determine the piezoelectric constant base on the energy approach method. An experimental and analytical procedure has been developed to determine the piezoelectric coupling coefficient and results validation. The nanogenerator package was modeled as a multilayer structure. The excitation method for the nanogenerator package was dropping a ball on the sample from different heights. The determinations of electrospun nanogenerator coupling coefficients are an important factor in the final application of these types of nanogenerators that have not been studied yet.     

Effect of electrospinning parameters on piezoelectric properties of electrospun PVDF nanofibrous mats under cyclic compression

The high piezoelectric response capacity of electrospun PVDF nanofibers is currently a challenging area of research, and this study attempts to optimize the piezoelectric properties of electrospun PVDF nanofibrous mat under controlled electrospinning process. Some experiments were designed to study the relationship between electrospinning processing parameters and the piezoelectric properties of PVDF mats under cyclic compression, and this relationship was compared with the change of crystalline structure features with the electrospinning parameters. The excitation method is based on low velocity compression test by cyclically pressing flat contactor on samples. The impact of each of processing parameters has been investigated. It was found that three electrospinning parameters including: applied voltage, feeding volume flow rate and syringe needle tip diameter, are significant influential factors to the piezoelectric properties of the electrospun PVDF nanofibrous mats. However, the feeding volume flow rate has a greater effect on the piezoelectric responses to cyclic compression than both applied voltage and volume flow rate does, and its effect on the piezoelectric responses is different from that of β-phase fraction of crystalline structure within PVDF nanofiber. It was also observed that the relationship between the piezoelectric peak intensity and the applied voltage as well as the feeding volume flow rate is nonlinear.     

Comparative evaluation of piezoelectric response of electrospun PVDF (polyvinilydine fluoride) nanofiber with various additives for energy scavenging application

Energy harvesting using piezoelectric nanomaterial provides an opportunity for advancement toward self-powered electronics. The fabrication complexity and limited power output of these nano/micro generators have hindered these advancements. This paper introduced a ?exible and light weight nanogenerator package that was obtained by variety of additives (ZnO, CNT, LiCl, PANI) and try to have comparisons between them to choose appropriate one base on final application. Performances of these additives were evaluated using Fourier Transform Infrared, Scanning Electron Microscopy, Impedance analyzer, and traction-compression machine. The excitation method is based on low velocity impact test by falling down a ball on samples. Results show that for all additives there is a direct connection between β phase formation and output voltage. CNT nanoparticles lead to have more β Phase formation and higher output voltage (0.9 V) for electrospun web with 230 μm thickness. The results imply promising applications, as an enhanced efficiency energy-scavenging interface, for various wearable self-powered electrical devices and systems.