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Xu MT, Zhu Y, Wei C, Liu L, Zhu Z, Tang ZH, Li YQ, Fu SY. Soft Artificial Muscle of Poly(vinyl chloride) Gel with an Imperceptible Liquid Metal Electrode. ACS APPLIED MATERIALS & INTERFACES 2024; 16:63851-63860. [PMID: 39509177 DOI: 10.1021/acsami.4c14409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2024]
Abstract
Electrodes with high electrical conductivity, yet good flexibility and mechanical compliance, are critical for electroactive artificial muscles. Herein, a promising liquid metal (LM) electrode is proposed by transforming eutectic gallium-indium (EGaIn) LM with high surface tension into paste-like LM with solid Ga2O3 shells. The developed compliant LM electrode not only shows high conductivity and negligible additional stiffness but also displays excellent electrical stability during cyclic actuation. Based on the LM electrode, the poly(vinyl chloride) gel (PVCG) artificial muscle developed exhibits the maximum actuation strain of 18.7% at a low electric field strength of 9 V μm-1 and maintains excellent durability without obvious performance attenuation after 10,000 s. A comparison shows that the as-developed PVCG artificial muscle is superior over that based on widely used carbon electrodes. Moreover, an artificial upper limb and crawling worm were manufactured to explore the great potential of PVCG artificial muscle in the robotic field. In addition, the practical application demonstration of the PVCG artificial muscle in the biomimetics field is also successfully fulfilled through the design of reasonable structures. Due to its easy fabrication, excellent electrical conductivity, and high mechanical compliance, the newly developed LM electrode is promising for high-performance PVCG artificial muscles in bionic robots.
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Affiliation(s)
- Meng-Ting Xu
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, China
| | - Yu Zhu
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, China
| | - Chang Wei
- School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Lei Liu
- School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zicai Zhu
- Shaanxi Key Laboratory of Intelligent Robots, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhen-Hua Tang
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, China
- Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
| | - Yuan-Qing Li
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, China
| | - Shao-Yun Fu
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, China
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Li F, Wang L, Gao L, Zu D, Zhang D, Xu T, Hu Q, Zhu R, Liu Y, Hu BL. Reducing Dielectric Loss of High-Dielectric-Constant Elastomer via Rigid Short-Chain Crosslinking. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2411082. [PMID: 39380411 DOI: 10.1002/adma.202411082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Revised: 09/14/2024] [Indexed: 10/10/2024]
Abstract
High-dielectric-constant elastomers have broad applications in wearable electronics, which can be achieved by the elastification of relaxor ferroelectric polymers. However, the introduction of soft long chains, with their high mobility under strong electric fields, leads to high dielectric loss. Given the relatively low modulus of relaxor ferroelectric polymers, elastification can be realized by introducing short-chain crosslinkers. In this work, a molecular engineering design is employed, utilizing a rigid short-chain crosslinker to create crosslinks with relaxor ferroelectric polymer, resulting in intrinsic elastomers characterized by a high dielectric constant but low dielectric loss. The obtained intrinsic ferroelectric elastomer possesses a high dielectric constant (35 at 1 kHz and 25 °C) and a low dielectric loss (0.09). Furthermore, this elastomer exhibits stable ferroelectric response and relaxor characteristics even under strains up to 80%. The study supplies a simple but effective method to reduce the dielectric loss of high-dielectric-constant intrinsic elastomers, thereby expanding their application fields in wearable electronics.
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Affiliation(s)
- Fangzhou Li
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Linping Wang
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Liang Gao
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Da Zu
- Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Dongyang Zhang
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Tianhua Xu
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Qiuyue Hu
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Ren Zhu
- Oxford Instruments Asylum Research, Shanghai, 200233, China
| | - Yunya Liu
- Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Ben-Lin Hu
- Advanced Interdisciplinary Sciences Research (AIR) Center, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
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Song ZQ, Wang LM, Liang Y, Wang XD, Zhu S. Microscopic in situ observation of electromechanical instability in a dielectric elastomer actuator utilizing transparent carbon nanotube electrodes. SOFT MATTER 2024; 20:6971-6983. [PMID: 39171405 DOI: 10.1039/d4sm00596a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Electromechanical instability (EMI) restricts the performance of dielectric elastomer actuators (DEAs), leading to premature electrical breakdown at a certain voltage. However, macro-level observations using traditional carbon grease electrodes have failed to capture the detailed features of EMI. In this study, we investigated EMI at the microscopic scale by fabricating transparent and conductive single-walled carbon nanotube (SWCNT) electrodes. Our findings reveal that EMI predominantly occurs in highly localized regions with dimensions on the order of tens of micrometers. This snap-through instability is likely induced by pre-existing defects within the elastomer, such as air voids or conductive particles, which reduce the critical voltage required for EMI in the flawed areas. From the perspective of phase transition principles, these defects act as heterogeneous nucleation sites for new phase embryos, thereby lowering the energy barrier for the electromechanical phase transition (i.e., EMI) compared to homogeneous nucleation in an ideally impurity-free elastomer. This study clarifies the longstanding discrepancy between theoretically predicted deformation bursts and the experimentally observed macroscopic continuous expansion of DEAs under low pre-stretch conditions. Additionally, it underscores the critical importance of material purity in mitigating electromechanical instability.
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Affiliation(s)
- Zhen-Qiang Song
- Center for Advanced Structural Materials, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, China.
- Hebei Key Lab for Optimizing Metal Product Technology and Performance, Yanshan University, China
| | - Li-Min Wang
- Center for Advanced Structural Materials, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, China.
| | - Yongri Liang
- Center for Advanced Structural Materials, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, China.
| | - Xiao-Dong Wang
- School of Civil Engineering and Mechanics, Yanshan University, China
| | - Shijie Zhu
- Department of Intelligent Mechanical Engineering, Fukuoka Institute of Technology, Japan.
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Wu Y, Zhao Y, Wang D. Preparation of Progressive Driving Bilayer Polymer-Dispersed Liquid Crystals Possessing a PDLC-PVA-PDLC Structure. Molecules 2024; 29:508. [PMID: 38276586 PMCID: PMC10819776 DOI: 10.3390/molecules29020508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
In this paper, the bilayer polymer-dispersed liquid crystals possessing a PDLC-PVA-PDLC structure were prepared by integrating two monolayer PDLCs. The effect of the polymer mesh size on the electro-optical properties of a bilayer PDLC was investigated by comparing the micro-morphology and electro-optical curves under different polymerization conditions. In addition, the impact of doping MoO2 nanoparticles with surface modification on the comprehensive performance of the bilayer PDLC was further researched. The contrast ratio of the bilayer PDLC prepared under the optimal conditions was improved by more than 90% and still maintained excellent progressive driving performance. Therefore, the development of a bilayer PDLC with optimal electro-optical properties will significantly enhance the technological prospects for the application of PDLC-based devices in smart windows, displays, and flexible devices.
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Affiliation(s)
- Yongle Wu
- Xi’an Key Laboratory of Advanced Photo-Electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi’an 710123, China; (Y.W.); (Y.Z.)
- Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuzhen Zhao
- Xi’an Key Laboratory of Advanced Photo-Electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi’an 710123, China; (Y.W.); (Y.Z.)
| | - Dong Wang
- Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Zang W, Wang Y, Wu W, Yao J, Hao X, Yu B, Wu D, Cao PF, Jiang Y, Ning N, Tian M, Zhang L. Superstretchable Liquid-Metal Electrodes for Dielectric Elastomer Transducers and Flexible Circuits. ACS NANO 2024; 18:1226-1236. [PMID: 38153997 DOI: 10.1021/acsnano.3c12210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
Dielectric elastomer transducers (DETs), with a dielectric elastomer (DE) film sandwiched between two compliant electrodes, are highly sought after in the fields of soft robotics, energy harvesting, and human-machine interaction. To achieve a high-performance DET, it is essential to develop electrodes with high conductivity, strain-insensitive resistance, and adaptability. Herein, we design an electrode (Supra-LMNs) based on multiple dynamic bond cross-linked supramolecular networks (Ns) and liquid metal (LM), which realizes high conductivity (up to 16,000 S cm-1), negligible resistance changes at high strain (1.3-fold increase at 1000% strain), instantaneous self-healability at ambient temperature, and rapid recycling. The conductive pathway can be activated through simple friction by transmitting stress through the silver nanowires (AgNWs) and cross-linking sites of LM particles. This method is especially attractive for printing circuits on flexible substrates, especially DE films. Utilized as dielectric elastomer generator (DEG) electrodes, it reduces the charge loss by 3 orders of magnitude and achieves high generating energy density and energy conversion efficiency on a low-resistance load. Additionally, serving as sensor (DES) and actuator (DEA) electrodes, it enables a highly sensitive sensing capability and complex interaction.
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Affiliation(s)
- Wenpeng Zang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yuhao Wang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wenju Wu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jiashuai Yao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xuesong Hao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bing Yu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Daming Wu
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Peng-Fei Cao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yingjie Jiang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Nanying Ning
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Ming Tian
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Liqun Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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Choi H, Jeong U. Purposive Design of Stretchable Composite Electrodes for Strain-Negative, Strain-Neutral, and Strain-Positive Ionic Sensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2306795. [PMID: 37689978 DOI: 10.1002/adma.202306795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/18/2023] [Indexed: 09/11/2023]
Abstract
Soft ionic sensors have emerged as a promising device form to accommodate various future electronic applications. One of the hurdles in ionic sensors is that the sensing signals by mechanical deformation and other stimuli are mixed up. Although the performance of the ionic sensors is highly dependent on the structure of electrodes, systematic investigation of purposive electrode design has been rarely explored. This study proposes a simple strategy for designing stretchable composite electrodes which make the ionic sensor strain-negative, strain-neutral, and strain-positive. This study reveals that such strain-responses can be obtained by adjusting the surface coverage of the electrically-effective conductive fillers. On the basis of the concept, deposition of a Au film on an elastomer composite and crack formation of the Au film are presented for the practical fabrication of a highly reproducible strain-neutral ionic sensor. A completely strain-independent temperature sensor is demonstrated by using the Au crack-based ionic sensor. In addition, this study demonstrates a two-terminal shear sensor capable of recognizing shear directions by combining the strain-positive and strain-negative electrodes.
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Affiliation(s)
- Hyeongseok Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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