钯型离子聚合物-金属复合材料的制备工艺参数优化研究

主要研究钯电极型离子聚合物-金属复合材料(Pd-ionic polymer-metal composite,Pd-IPMC)的制备工艺。以增加Pd-IPMC的电致动位移为优化目标,采用正交优化方法,针对浸泡还原镀和化学镀两个核心步骤进行了参数优化,探索了主要工艺参数对材料电致位移的影响规律。实验结果给出了工艺参数的优化值,以及这些参数对材料性能的影响水平和效应曲线。由优化后工艺参数制备的Pd-IPMC性能较优化前有显著提高,且优于ERI公司商业化的IPMC。研究结果充分验证了Pd作为IPMC电极的可行性,解决了现有Pd-IPMC材料致动性能不理想的难题,对于制备低成本、大变形的IPMC材料,并促进其工程应用具有重要意义。     

离子聚合物-金属复合材料的研究进展

离子聚合物-金属复合材料(IPMC)是一类电活性材料,可作为柔性致动器和传感器,因在仿生学领域有广阔的应用前景而成为材料科学的研究热点之一。概述了IPMC的研究现状,包括IPMC的致动原理,基质膜材料的结构、制备及性质以及电极的制备方法及工艺。基于材料组成结构对IPMC基质膜进行了分类,详细讨论了膜材料的化学结构与其质子交换能力、溶胀性、吸水率、致动力、形变性等性能的关系,并分析了各类材料的特点及局限性;讨论了IPMC电极制备方法及工艺,分析了电极制备方法与其性能的关系;通过归纳总结IPMC组成结构对其性能的影响规律,探讨改进IPMC性能的方法,并展望了该类材料的发展前景。     

具有梯度结构的三维IPMC的制备及表征

离子聚合物金属复合材料(ionic polymer metal composite,IPMC)是一种离子型电活性聚合物,具有驱动电压低、位移变形量大、反应迅速和质量轻等优点,作为新型的电致动材料具有广阔的应用前景。但是现有的IPMC电致动材料存在输出力小和非水工作时间短的缺点。通过制备厚度上具有梯度变化的三维IPMC来提高IPMC的驱动性能;采用不易电解挥发、稳定性较好的乙二醇作为IPMC的工作介质,延长IPMC的非水工作时间。研究结果表明,在相同幅值的正弦交流电压下,具有一定梯度结构的IPMC能够显著提高其形变位移和输出力,幅值为3.5V时,形变位移和输出力较相同质量厚度的平面型IPMC分别提升了7.0%和47.9%;用乙二醇置换水作为工作介质的平面型IPMC,其非水工作时间得到大幅提升,从150s延长至300s。IPMC电机械输出性能的提升和非水工作时间的延长对于IPMC在驱动领域的进一步应用开发具有重要意义。     

采用梯度功能方法的IPMC弹性模量改进模型

采用梯度功能材料力学方法,通过改进层合板理论模型来预测材料的力学性能。将饱和掺杂金属原子的外层作为表面镀层,将无掺杂的基体作为中间层,两层之间掺杂的金属原子含量逐渐变化,作为梯度层;使用EDS方法得到了Pt型金属/离子聚合物复合材料(IPMC)沿厚度方向的Pt原子含量分布,证明了模型分层的合理性;采用ASTM标准测定了IPMC材料的拉伸和弯曲弹性性能。本模型采用Mori-Tanaka方法预测表面镀层和梯度层的弹性性能,采用梯度力学方法,最终得到IPMC材料整体的弹性性能。用本文中模型预测常态下和含水饱和态下的IPMC拉伸性能与实验值相比,误差分别为 0.69%和-2.05%;预测常态下IPMC的表观弯曲弹性模量与实验值相比,误差为-0.99%。     

图案化电极的离子聚合物金属复合物扭转特性研究

离子聚合物金属复合物(ionic polymer metal composite,IPMC)是一种新型离子型电致动聚合物,具有在低电压驱动下产生大变形的特点而有广阔的应用前景。通过在IPMC表面制作图案化电极,使其在电压驱动下实现扭转运动。针对图案化电极的结构尺寸对其扭转特性的影响进行研究,得到图案化电极IPMC的扭转特性规律。同时针对贴合方式IPMC的结构尺寸变化对其扭转特性的影响进行研究,并比较两种IPMC的扭转运动效果,得出制备可实现扭转运动IPMC的影响因素。     

方柱状IPMC制备与驱动性能的研究

离子型聚合物金属复合物(ionic polymer-metal composites, IPMC)是一种离子型电致动聚合物材料,具有尺寸小、质量轻、驱动电压低、形变量大以及生物兼容性好等众多优点。但传统片状IPMC只能在单一方向上运动的缺点,极大地限制了IPMC的应用。因此,通过溶液浇铸和化学镀的方法制备出一种可实现多自由度运动的方柱状IPMC,并对其表面电极进行了SEM观测和驱动性能表征分析。通过对比方柱状IPMC在正弦、方波和直流电压信号下的末端位移和输出力变化情况,发现方柱状IPMC在这3种电压信号驱动下均具有较好的驱动性能,且在直流电压信号下末端位移和输出力最大。通过对方柱状IPMC在不同运动方向的测试结果进行对比分析,探究了方柱状IPMC在介入式手术导管导向装置上应用的可行性。     

离子聚合物-金属复合物材料的研究进展

离子聚合物-金属复合物(IPMC)是具有电响应特性的复合材料,既能作为致动器又可以用作传感器,具有广泛的应用前景,是材料领域研究的热点。概述了IPMC的制备过程及致动机理,从IPMC的离子交换膜材料和电极材料研究方面综述了IPMC的发展情况,并介绍了材料的组成和结构对IPMC的响应速度、弯曲位移、输出力等性能的影响。探讨了IPMC目前存在的问题,并展望未来的发展前景。     

Ag型IPMC柔性驱动器的制备及性能

为了降低成本并改善材料性能,采用银替代铂制备IPMC电极。基于渗透还原工艺采用化学沉积方法制备了Pt基、Pt-Ag基和Ag基三种IPMC柔性驱动器试件。对试件的SEM和XRD分析结果表明本文提供的方法可以有效地将电极金属沉积在基膜中,且呈梯度分布;对样件的致动效果以及表面电阻特性测试结果表明Ag基IPMC驱动器具有最好的致动变形能力和最低的表面电阻。在相同尺寸与约束条件下,Ag基IPMC在1.5V时产生90°变形,Pt型与Pt-Ag型IPMC分别在3V和4V驱动电压下产生60°变形。     

IPMC的力输出特性

IPMC(ion-exchange polymer metal composite)离子交换聚合物-金属复合材料)是一种人工肌肉材料,其较低的驱动电压能产生较大的位移变形,研究了IPMC这种智能材料的输出力特性.实验选取了不同电压幅值,不同频率的方波、三角波、正弦波3种波形作为电激励信号,通过力传感器实测了IPMC试样末端的输出力.结果表明,随着电压幅值的增大,其输出力也增大;随着电刺激信号频率的降低,其输出力也增大;而波形对其输出力影响不显著.     

一种离子交换树脂金属复合材料(IPMC)的力学参数测定

对一种新型的人工肌肉材料--离子交换树脂金属复合材料(IPMC)的力学性能参数进行了测试研究.进行了精密拉伸实验,测定了其弹性模量E和泊松比v,确定了其本构关系,证实了其具有各向同性特性.测试研究为开展IPMC人工肌肉和其应用研究提供了参考数据.     

Nanomechanical and nanotribological characterization of noble metal-coated AFM tips for probe-based ferroelectric data recording

Probe-based data recording is being developed as an alternative technology for ultrahigh areal density. In ferroelectric data storage, a conductive atomic force microscope (AFM) probe with a noble metal coating is placed in contact on lead zirconate titanate (PZT) film, which serves as the ferroelectric material. A crucial mechanical reliability concern is tip wear during contact of the ferroelectric material with the probe. To achieve high wear resistance, the mechanical properties (such as elastic modulus and hardness) of the metal-coated probe should be high. Nanoindentation experiments were performed in order to evaluate the mechanical properties of four commercial noble metal coatings, namely, Pt, Pt-Ni, Au-Ni and Pt-Ir, deposited on AFM probes. The effective hardness and elastic modulus were evaluated, using a contact mechanics model that accounts for the effect of the underlying silicon substrate. The Pt-Ir coating was found to exhibit the highest hardness, highest elastic modulus and lowest creep resistance. Nanoscratch studies reveal that the noble metal coatings are removed primarily by plastic deformation. The Pt-Ir and Pt coatings show the highest and lowest scratch resistance, respectively, which is consistent with results obtained from wear tests of the noble metal-coated AFM probes on a PZT surface.     

The modeling and determination of dynamic elastic modulus of magnesium based metal matrix composites

The aim of the present study was to determine elastic modulus of the magnesium-based composites containing different volume fraction of SiC particulates using an innovative free-free beam type impact based technique. This technique is based on classical vibration theory, by which the geometry and material properties of the metal matrix composites are related to resonant frequency of the test specimen. With the fundamental resonant frequency obtained from the experiment and density determined by the Archimedes' principle, the elastic modulus values were determined. In addition, a finite element model is proposed for different SiC weight percentage samples for the determination of dynamic elastic modulus using the first natural frequency corresponding to the flexural mode. The elastic modulus values obtained using finite element method were found to be in close agreement with the values obtained from the impact based experiments and in better agreement when compared to theoretical methods such as Halpin-Tsai method. Both the theoretical approaches, in common, exhibit the increasing trend of elastic modulus value with an increase in weight percentage of SiC particulates.     

Modelling and determination of dynamic elastic modulus of magnesium based metal matrix composites

Abstract

The aim of the present study was to determine the elastic modulus of magnesium based composites containing different volume fractions of SiC particulate using an innovative suspended beam type impact based technique. This applies classical vibration theory, which relates the resonant frequency of the test specimens to the geometry and material properties of the metal matrix composites. The elastic modulus values were determined from the funda mental resonant frequency obtained from the experiment and density measurements. In addition, a finite element model was proposed for determining the dynamic elastic modulus of MMCs with different SiC reinforcement content using the first natural frequency corresponding to the flexural mode. The elastic modulus values obtained from the finite element model were in close agreement with the values obtained from the impact based experiments and in better agreement than those from theoretical methods such as the shear lag, Eshelby, and Halpin–Tsai models.     

Carbon Nanotube and Graphene‐based Bioinspired Electrochemical Actuators

Bio‐inspired actuation materials, also called artificial muscles, have attracted great attention in recent decades for their potential application in intelligent robots, biomedical devices, and micro‐electro‐mechanical systems. Among them, ionic polymer metal composite (IPMC) actuator has been intensively studied for their impressive high‐strain under low voltage stimulation and air‐working capability. A typical IPMC actuator is composed of one ion‐conductive electrolyte membrane laminated by two electron‐conductive metal electrode membranes, which can bend back and forth due to the electrode expansion and contraction induced by ion motion under alternating applied voltage. As its actuation performance is mainly dominated by electrochemical and electromechanical process of the electrode layer, the electrode material and structure become to be more crucial to higher performance. The recent discovery of one dimensional carbon nanotube and two dimensional graphene has created a revolution in functional nanomaterials. Their unique structures render them intriguing electrical and mechanical properties, which makes them ideal flexible electrode materials for IPMC actuators in stead of conventional metal electrodes. Currently although the detailed effect caused by those carbon nanomaterial electrodes is not very clear, the presented outstanding actuation performance gives us tremendous motivation to meet the challenge in understanding the mechanism and thus developing more advanced actuator materials. Therefore, in this review IPMC actuators prepared with different kinds of carbon nanomaterials based electrodes or electrolytes are addressed. Key parameters which may generate important influence on actuation process are discussed in order to shed light on possible future research and application of the novel carbon nanomateials based bio‐inspired electrochemical actuators.     

Effect of fiber coating on the longitudinal damping capacity of fiber-reinforced metal matrix composites

A novel model for calculating the damping capacity of continuous fiber-reinforced metal matrix composites (FMMCs) is proposed based on the viewpoint of energy loss. Finite element method (FEM) has been employed to investigate the effect of fiber coating on the longitudinal damping capacity of a composite by varying the thickness and the material properties of the coating. The results show that the damping of a composite containing the elastic coating increases with a decrease in the elastic modulus of the coating, while for the case of plastic coating, the weak coating or the high elastic modulus coating may help in improving the overall damping of composite.     

Elastic properties of powders during compaction. Part 1: Pseudo-isotropic moduli

The elastic moduli of powdered materials undergoing uniaxial compaction was investigated, paying particular attention to effects of solid phase material properties and initial particle shape. Elastic properties were characterised by the isotropic elastic moduli Poisson’s ratio and Young’s modulus, calculated from elastic wave speeds measured in the axial (pressing direction). To isolate material property effects, three different ductile metal powders (copper, stainless steel, and aluminium) with equivalent particle shape (spheroidal) were tested. Comparison with similar measurements for a brittle spheroidal powder (glass) illustrated that solid phase yield mechanism affects the evolution of pore character, and hence bulk elastic properties of the powder compact. Pore character was also studied separately by comparing copper powders with differing particle shapes (spheroidal, irregular, and dendritic). For all powders, Young’s modulus increased monotonically with compaction (reducing porosity). For the ductile spheroidal powders, differences in evolution of Young’s modulus with compaction were accounted for by solid phase elastic properties. The different morphology copper powders showed an increase in compact compliance as particle (pore) ruggedness increased. Poisson’s ratio followed a concave porosity dependence: decreasing in the initial stages of compaction, then increasing as porosity approached zero. Comparison between powders indicated the initial decrease in Poisson’s ratio was insensitive to solid phase material properties. However, as the compact approached solid phase density, the Poisson’s ratio—porosity locus diverged towards corresponding solid phase values for each particle material, indicating an influence of solid phase elastic properties.     

IPMC材料的性能稳定性及封装工艺研究

制备了镀钯型离子聚合物-金属复合材料(Pd型-IPMC),探索了含水量对IPMC材料松弛效应的影响,在此基础上采用聚四氟乙烯(PTFE)与硅橡胶(PDMS)相结合的封装工艺对IPMC材料进行封装,实验结果表明,采用此方法封装后的材料无松弛,响应迅速,致动性能好,工作性能稳定,解决了长期以来该材料用作驱动器的难题,为该材料的应用奠定了基础。     

离子聚合物金属复合材料传感特性研究

理论分析了离子聚合物金属复合材料(ionic polymer metal composites,简称IPMC)的传感机理和数学模型;主要针对其传感性能进行了实验研究,给出了在不同工作频率下的传感器标定曲线与灵敏度测试结果,并分析了其灵敏变化原因;最后对传感器进行的重复性能的测试.实验结果表明,IPMC传感器线性度好、重复性能好、在低频范围内灵敏度较高、检测结果稳定可靠.     

离子聚合物-金属复合材料(IPMC)的电极界面研究进展

离子聚合物-金属复合材料(Ionic polymer-metal composites,IPMC)是一种新型的智能材料,由于其具有良好的机电转换能力且本体柔软,可以制作成多种驱动器和传感器,因而在各个领域中展示出巨大的应用潜力。这种材料的机电性能受多种因素影响,其电极界面是重要影响因素之一。文章回顾了近几年来国内外针对IPMC材料的界面电极特性所做的研究工作,归纳了优化电极界面的主要措施,并提出一种有效提高IPMC材料电极界面的制备工艺设计思路。