Ionic polymer metal composites actuators with enhanced driving performance by incorporating graphene quantum dots

In order to further improve the driving performance of ionic polymer metal composites(IPMCs),Nafion/graphene quantum dots(GQDs)hybrid membranes incorporating GQDs with various contents of 0,0.1 wt.%,0.5 wt.%,1.0 wt.%,2.0 wt.%and 4.0 wt.%were fabricated by solution casting,and then IPMCs were manufactured by electroless plating.The water contents and elastic moduli of the hybrid membranes were tested.The morphology characteristics of the hybrid membranes and the IPMCs were observed,and the current,AC impedance,blocking force and displacement of the IPMCs were measured.The results show that the elastic modulus of the hybrid membranes decreases,the water content increases,and the actuation performance of the IPMCs improves significantly after the addition of GQDs.IPMC with 1.0 wt.%GQDs exhibits the best driving property.Compared with the IPMC without GQDs,the working current,ion conductivity,blocking force,and tip displacement increase by 94.67%,311.11%,53.66%,and 66.07%,respectively.These results lay a solid foundation for the preparation of IPMCs with high performance,and further broaden their applications in biomedical devices and bionic robots.

Thermo-and photo-driven soft actuators based on crosslinked liquid crystalline polymers

Crosslinked liquid crystalline polymers（CLCPs） are a type of promising material that possess both the order of liquid crystals and the properties of polymer networks.The anisotropic deformation of the CLCPs takes place when the mesogens experience order to disorder change in response to external stimuli; therefore,they can be utilized to fabricate smart actuators,which have potential applications in artificial muscles,micro-optomechanical systems,optics,and energyharvesting fields.In this review the recent development of thermo-and photo-driven soft actuators based on the CLCPs are summarized.

TEOS-GO掺杂的银基离子聚合物金属复合材料的制备及其致动性能

离子聚合物金属复合材料(IPMC)是一种新型的电驱动软材料,具有质量轻、驱动电压低的优点,但也存在输出力较小、驱动时间短的缺点,限制了其应用前景。提出了一种在基膜内掺杂硅酸乙酯-氧化石墨烯(TEOS-GO)以提高保水性和驱动能力的银基IPMC,通过对纯Nafion IPMC与TEOS-GO/Nafion IPMC致动器的含水量、尖端位移、输出力和稳定性等参数的测试,证实优化后IPMC的驱动性能有明显的提升。实验结果表明,掺杂质量分数1.5%TEOS-GO的IPMC在3 V直流电压下,尖端位移达到16.579 mm,相当于纯Nafion IPMC的3.37倍;输出力最高达到0.439 gf(1 gf=9.8 mN),是纯Nafion IPMC的5倍。这种改进方式弥补了IPMC用于致动器的缺点,为今后的发展开拓了前景。

基于CMWCNT/Nafion的增强型离子聚合物金属复合材料的制备及致动性能

离子聚合物金属复合材料(IPMC)是一种新型的电活性材料,具有体积小、质量轻、驱动电压低等优点,但驱动力小、稳定工作时间短等问题限制着其柔性致动性能。提出了一种基于银基IPMC的增强型致动器,通过在IPMC的基底聚合物中掺杂羧基化多壁碳纳米管(CMWCNT),来提高IPMC的整体机械性能和致动性能。其中,掺杂质量分数0.5%CMWCNT的IPMC的最大尖端位移和驱动力分别增加至未优化银基IPMC的1.60倍与2.32倍,该性能的提升归因于CMWCNT良好的导电性和羧基对水合阳离子迁移的加速作用。与未优化的银基IPMC相比,掺杂质量分数0.5%CMWCNT时IPMC驱动速率可提升至3.57倍。研究结果可为IPMC在各领域的应用发展提供参考。

超弹性介电型EAP圆柱形驱动器变激励电压下动态响应分析

超弹性电活性聚合物(electroactive polymer,EAP)圆柱形驱动器的动态特性是进行合理设计、使用及优化驱动器的重要依据。结合介电型EAP机电耦合方程,构建了驱动器轴向线性运动的动力学方程。通过计算得到驱动器的电压-轴向位移曲线,研究了驱动器在准静态点附近的稳定性。最后,分析了驱动器在施加阶跃和周期电压激励时的动态响应。结果表明,在有效工作范围内驱动器是稳定的,阶跃电压激励使驱动器在准静态点附近产生轴向振动,周期电压使驱动器产生包含自振的拟周期轴向振动。进一步分析表明,阶跃电压激励更易导致驱动器的电击穿失效。

基于团簇微观结构分析的离子电活性聚合物驱动特性

首先,对离子交换膜吸附水分子微观过程进行分析,并结合团簇结构揭示离子电活性聚合物的传质动力学特性;其次,基于溶胀理论研究团簇受力情况,依据几何变形特点和变形传质机理建立物理模型;最后,对得到的驱动模型进行验证和分析讨论。研究结果表明:本文模型所得结果和实验结果较吻合。含水量对离子交换膜团簇通道的形成有重要影响,阳离子的迁移以及水分子运动是离子交换膜驱动的主控因素。随着阳离子浓度和水分子浓度增加,静水压力、渗透压力以及静电压力均逐渐增大,渗透压力对离子电活性聚合物弯曲变形起主导作用。

介电型EAP驱动的转动关节研究

基于介电型电活性聚合物(EAP)的优点,设计、实现了该材料驱动的转动关节。根据介电型EAP的变形原理设计、制作了圆柱形驱动器,其输出最大位移约为11mm,伸长应变达到33.8%,并对输出力-位移特性进行测试。基于该型驱动器实现了转动关节,转角约为±13°,堵转力矩为19.6mN.m,将转动关节应用于爬行机器人,并对试验结果进行分析。

随心而变——多响应超疏水智能致动材料

智能致动器具有将外界刺激转化为机械运动的能力,在软体机器人、人造肌肉、传感器、智能皮肤等领域具有广阔的应用前景。本新创实验通过在聚酰亚胺高分子膜表面涂覆聚二甲基硅氧烷预聚体,并喷涂石墨烯乙醇分散液,制备出一种可以利用高分子材料的热膨胀系数差异对光、电、热等刺激产生响应的超疏水智能材料。从中国传统剪纸艺术和仿生结构获得灵感,将所得超疏水材料加工成爪形构造和可变形集水装置,利用材料的超疏水性质实现其在强酸,强碱等复杂应用环境下的稳定运行。此外,通过调整刺激电流大小实现了材料致动能力的智能化编程,进一步提升了新创实验的可控性和应用性。本新创实验融汇无机化学、高分子化学、仪器分析和材料化学等多个化学学科,实现理论与应用的巧妙衔接。所选用的实验原料无毒且易得,符合绿色化学的要求,体现了实验的可持续性。通过开发新型材料的制备技术,有效提升了材料的致动性能,极大地拓展了材料的应用场景。该新创实验现象明显,操作过程趣味性强,有助于激发学生的科研兴趣,提高学生的知识应用水平,培养学生的创新意识,同时提升学生的综合素质。该实验对学生的学习和成长具有积极的促进作用。

介电型EAP柔性摆动驱动器研究

为研究介电型EAP摆动驱动器的性能,设计制作了柔杆式介电型EAP摆动驱动器。对驱动器的摆动性能进行了测试,获得了不同施加电压下驱动器的摆动角度与阻转力。结果表明,随着施加电压的增加,驱动器的摆动角度、阻转力也在增加,且在电压较大时增加更快。此外,EAP的拉伸率对驱动器性能也有一定的影响,并指出了该驱动器在结构与性能优化的基础上,可潜在用于仿生机器人的摆动驱动。

基于EAP驱动器的并联式管道机器人机构设计

电活性聚合物是一类较新的聚合物,其高效的电能和机械能转换特性可用于驱动器的开发。本文介绍EAP材料作为驱动器的机理以及EAP移动、转动驱动器的设计,并与其他功能材料的驱动特性进行了比较;提出了一种基于EAP驱动器的并联式管道机器人机构,对其管道内行走运动进行了规划;该机器人具有较强的非结构环境适应性。

介电型EAP线性和弯曲驱动器研究

基于介电型EAP(dielectric electroactive polymer,电活性聚合物)较好的综合性能,研究了卷绕式线性和弯曲驱动器。分析了线性驱动器的结构,进行了单(两)自由度弯曲驱动器的电极形式设计,构建了双轴拉伸机构和卷绕平台用于驱动器制作。试验表明:线性和弯曲驱动器能产生线性伸长和单(两)自由度连续弯曲,其中线性伸长率超过30%,弯曲角度可达90°(32°),并测试了驱动器的输出力。卷绕式驱动器结构紧凑,运动范围大,能产生类似于生物体的柔性运动,在仿生空中或地面机器人等领域具有广泛应用前景。

锥形电活性聚合物薄膜作动器的力电响应研究

以一款锥形电活性聚合物薄膜作动器为研究对象,选用Ogden材料模型对作动器进行数值计算。控制外力变化,对薄膜在变形状态下的应变量、厚度及临界电场强度进行分析,研究了预拉伸对薄膜力电稳定性的影响。结果表明:外力增加会显著提高薄膜内各点的径向应变,减小膜厚,并使得临界电场强度的分布发生改变;薄膜预拉伸程度的增加,也会提高薄膜临界电场强度,使得薄膜的力电稳定性得到增强。

EAP换能单元发电量的影响因素分析

电活性聚合物(EAP)作为一种新型电活性软体功能材料,具有多种优点,用于能量收集具有巨大的应用潜力。该文从宏观和微观两个层面阐述了介电材料用于能量收集的机电转化原理,以EAP换能单元为例,说明了EAP换能单元怎样将机械能转化为电能,并阐述了介电弹性体发电机理,为后面EAP换能单元的发电提供理论依据。以其他学者研究得到影响EAP换能单元发电量的因素为基础,通过正交试验得到EAP换能单元发电特性和最佳工作条件,并对试验的可靠性进行了分析。实验结果表明,各因素对EAP材料发电的影响大小顺序为:EAP膜面积>拉伸位移>预加电压>预拉伸率>EAP膜厚度。换能单元最佳工作条件为预加电压1 000 V,预拉伸率400%,拉伸位移4 cm,膜面积62.41 cm^2,EAP膜厚度1 mm。

介电型EAP卷绕式驱动器的实现与应用

基于介电型EAP(electroactive polymer,电活性聚合物)的优点,以VHB4910作为驱动材料,设计、实现了卷绕式二自由度驱动器,它可产生轴向伸缩和弯曲运动。对驱动器的性能进行测试,其最大轴向位移为6.78 mm,最大轴向推拉力分别为9.56 N、9.81 N;最大弯曲角度达87°,最大侧向力为1.04 N。在驱动器两端安装两对单向轮,实现了一个可爬行运动的机器人,该机器人可通过驱动器的伸缩和弯曲向前运动,其伸缩运动速度为1.55 mm/s,弯曲运动速度可达6.41 mm/s。试验证明介电型EAP可以用于实现微小型爬行机器人。

Experimental study and electromechanical model analysis of the nonlinear deformation behavior of IPMC actuators

This paper develops analytical electromechanical formulas to predict the mechanical deformation of ionic polymer-metal composite (IPMC) cantilever actuators under DC excitation voltages. In this research, IPMC samples with Pt and Ag electrodes were manufactured, and the large nonlinear deformation and the effect of curvature on surface electrode resistance of the IPMC samples were investigated experimentally and theoretically. A distributed electrical model was modified for calculating the distribution of voltage along the bending actuator. Then an irreversible thermodynamic model that could predict the curvature of a unit part of an IPMC actuator is combined with the electrical model so that an analytical electromechanical model is developed. The electromechanical model is then validated against the experimental results obtained from Pt- and Ag-IPMC actuators under various excitation voltages. The good agreement between the electromechanical model and the actuators shows that the analytical electromechanical model can accurately describe the large nonlinear quasi-static deflection behavior of IPMC actuators.

Large nonlinear deflection behavior of IPMC actuators analyzed with an electromechanical model

This study presents an electromechanical engineering model for the analysis of the large deflection curves of ionic polymer-metal composite(IPMC)cantilever actuators under direct current(DC)voltages.In this paper,the longitudinal normal strain performance of the material was investigated using digital image correlation on a micro-scale.The deflection of the actuator is analytically obtained with the application of an elliptic integration method based on the relationship between strain gradient and excitation voltage,and the minimum excitation voltage is derived based on the assumption that the actuators have small deformations.The validity of the electromechanical model is then justified with the experimental results obtained from Pt-and Ag-IPMC actuators at various excitation voltages.The findings of this study confirm that the introduced electromechanical model can accurately describe the large nonlinear deflection behavior of IPMC actuators.

Correlation of Direct Piezoelectric Effect on EAPap under Ambient Factors

Direct piezoelectricity of electro-active papers （EAPap） is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, such as temperature, humidity, and strain rate, are applied and analyzed. Strong piezoelectricity of EAPap is found on the basis of the test results and in comparison with polyvinylidene fluoride （PVDF） and lead zirconate titanate （PZT）-5H. The maximum piezoelectric constant is achieved to be 504 pC/N. The reason of strong piezoelectricity of EAPap is discussed in this paper. The potential of EAPap as a biomimetic actuator and sensor is also investigated.

介电型EAP驱动的伸缩移动机器人研究

以介电型EAP为驱动材料,设计、制作了一种结构紧凑的圆柱形驱动器。模仿自然界无足爬行生物的运动机理,设计了基于该驱动器的可伸缩移动机器人,实现机器人的向前伸缩运动,验证了该介电型EAP驱动器在该类型机器人中的实用性。

EAP在浮标电源上的应用

简述了浮标电源的发展;电活性聚合物(EAP)是一种可以实现机械能和电能相互转换的智能材料,针对其在发电模式下工作时的发电原理进行了简要的分析研究;通过综述国外学者针对EAP发电方面的研究,证明了EAP波浪能发电的可能性,并进一步分析了EAP发电机作为浮标电源的新发展的可能性。

Electromechanical responses and instability of electro-active polymer cylindrical shells

Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and a static electric field, are studied. Deformation curves and distribution of stresses are obtained. It is found that an internal pressure together with an electric field may cause the unstable non-monotonic deforma- tion of the shell. It is also shown that a critical thickness for the shell exists, and the shell may undergo the unstable deformation if its thickness is less than this critical value. In addition, the effects of the electric field, axial stretch, thickness, and internal pressure on the instability of the shell are discussed.