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Li Y, Veronica A, Ma J, Nyein HYY. Materials, Structure, and Interface of Stretchable Interconnects for Wearable Bioelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2408456. [PMID: 39139019 DOI: 10.1002/adma.202408456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/24/2024] [Indexed: 08/15/2024]
Abstract
Since wearable technologies for telemedicine have emerged to tackle global health concerns, the demand for well-attested wearable healthcare devices with high user comfort also arises. Skin-wearables for health monitoring require mechanical flexibility and stretchability for not only high compatibility with the skin's dynamic nature but also a robust collection of fine health signals from within. Stretchable electrical interconnects, which determine the device's overall integrity, are one of the fundamental units being understated in wearable bioelectronics. In this review, a broad class of materials and engineering methodologies recently researched and developed are presented, and their respective attributes, limitations, and opportunities in designing stretchable interconnects for wearable bioelectronics are offered. Specifically, the electrical and mechanical characteristics of various materials (metals, polymers, carbons, and their composites) are highlighted, along with their compatibility with diverse geometric configurations. Detailed insights into fabrication techniques that are compatible with soft substrates are also provided. Importantly, successful examples of establishing reliable interfacial connections between soft and rigid elements using novel interconnects are reviewed. Lastly, some perspectives and prospects of remaining research challenges and potential pathways for practical utilization of interconnects in wearables are laid out.
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Affiliation(s)
- Yue Li
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, 00000, China
| | - Asmita Veronica
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, 00000, China
| | - Jiahao Ma
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, 00000, China
| | - Hnin Yin Yin Nyein
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, 00000, China
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2
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Choi SB, Noh T, Jung SB, Kim JW. Stretchable Piezoresistive Pressure Sensor Array with Sophisticated Sensitivity, Strain-Insensitivity, and Reproducibility. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2405374. [PMID: 39013112 DOI: 10.1002/advs.202405374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/07/2024] [Indexed: 07/18/2024]
Abstract
This study delves into the development of a novel 10 by 10 sensor array featuring 100 pressure sensor pixels, achieving remarkable sensitivity up to 888.79 kPa-1, through the innovative design of sensor structure. The critical challenge of strain sensitivity inherent is addressed in stretchable piezoresistive pressure sensors, a domain that has seen significant interest due to their potential for practical applications. This approach involves synthesizing and electrospinning polybutadiene-urethane (PBU), a reversible cross-linking polymer, subsequently coated with MXene nanosheets to create a conductive fabric. This fabrication technique strategically enhances sensor sensitivity by minimizing initial current values and incorporating semi-cylindrical electrodes with Ag nanowires (AgNWs) selectively coated for optimal conductivity. The application of a pre-strain method to electrode construction ensures strain immunity, preserving the sensor's electrical properties under expansion. The sensor array demonstrated remarkable sensitivity by consistently detecting even subtle airflow from an air gun in a wind sensing test, while a novel deep learning methodology significantly enhanced the long-term sensing accuracy of polymer-based stretchable mechanical sensors, marking a major advancement in sensor technology. This research presents a significant step forward in enhancing the reliability and performance of stretchable piezoresistive pressure sensors, offering a comprehensive solution to their current limitations.
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Affiliation(s)
- Su Bin Choi
- Department of Smart Fab Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Taejoon Noh
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Seung-Boo Jung
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jong-Woong Kim
- Department of Smart Fab Technology, Sungkyunkwan University, Suwon, 16419, South Korea
- Department of Semiconductor Convergence Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
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3
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Ma J, Sa Z, Zhang H, Feng J, Wen J, Wang S, Tian Y. Microconfined Assembly of High-Resolution and Mechanically Robust EGaIn Liquid Metal Stretchable Electrodes for Wearable Electronic Systems. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402818. [PMID: 38898769 DOI: 10.1002/advs.202402818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/24/2024] [Indexed: 06/21/2024]
Abstract
Stretchable electrodes based on liquid metals (LM) are widely used in human-machine interfacing, wearable bioelectronics, and other emerging technologies. However, realizing the high-precision patterning and mechanical stability remains challenging due to the poor wettability of LM. Herein, a method is reported to fabricate LM-based multilayer solid-liquid electrodes (m-SLE) utilizing electrohydrodynamic (EHD) printed confinement template. In these electrodes, LM self-assembled onto these high-resolution templates, assisted by selective wetting on the electrodeposited Cu layer. This study shows that a m-SLE composed of PDMS/Ag/Cu/EGaIn exhibits line width of ≈20 µm, stretchability of ≈100%, mechanical stability ≈10 000 times (stretch/relaxation cycles), and recyclability. The multi-layer structure of m-SLE enables the adjustability of strain sensing, in which the strain-sensitive Ag part can be used for non-distributed detection in human health monitoring and the strain-insensitive EGaIn part can be used as interconnects. In addition, this study demonstrates that near field communication (NFC) devices and multilayer displays integrated by m-SLEs exhibit stable wireless signal transmission capability and stretchability, suggesting its applicability in creating highly-integrated, large-scale commercial, and recyclable wearable electronics.
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Affiliation(s)
- Jingxuan Ma
- National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China
| | - Zicheng Sa
- National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China
| | - He Zhang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
- Advanced Biomedical Instrumentation Centre Limited, Hong Kong, 999077, China
| | - Jiayun Feng
- National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China
| | - Jiayue Wen
- Zhengzhou Research Institute, Harbin Institute of Technology, Zhengzhou, 450041, China
| | - Shang Wang
- National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China
- Zhengzhou Research Institute, Harbin Institute of Technology, Zhengzhou, 450041, China
| | - Yanhong Tian
- National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China
- Zhengzhou Research Institute, Harbin Institute of Technology, Zhengzhou, 450041, China
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4
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Zhan H, Wen B, Tian B, Zheng K, Li Q, Wu W. Printed Self-Healing Stretchable Electronics for Bio-signal Monitoring and Intelligent Packaging. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400740. [PMID: 38693082 DOI: 10.1002/smll.202400740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/27/2024] [Indexed: 05/03/2024]
Abstract
Integrating self-healing capabilities into printed stretchable electronic devices is important for improving performance and extending device life. However, achieving printed self-healing stretchable electronic devices with excellent device-level healing ability and stretchability while maintaining outstanding electrical performance remains challenging. Herein, a series of printed device-level self-healing stretchable electronic devices is achieved by depositing liquid metal/silver fractal dendrites/polystyrene-block-polyisoprene-block-polystyrene (LM/Ag FDs/SIS) conductive inks onto a self-healing thermoplastic polyurethane (TPU) film via screen printing method. Owing to the fluidic properties of the LM and the interfacial hydrogen bonding and disulfide bonds of TPU, the as-obtained stretchable electronic devices maintain good electronic properties under strain and exhibit device-level self-healing properties without external stimulation. Printed self-healing stretchable electrodes possess high electrical conductivity (1.6 × 105 S m-1), excellent electromechanical properties, and dynamic stability, with only a 2.5-fold increase in resistance at 200% strain, even after a complete cut and re-healing treatment. The printed self-healing capacitive stretchable strain sensor shows good linearity (R2 ≈0.9994) in a wide sensing range (0%-200%) and is successfully applied to bio-signal detection. Furthermore, the printed self-healing electronic smart label is designed and can be used for real-time environmental monitoring, which exhibits promising potential for practical application in food preservation packaging.
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Affiliation(s)
- Haoye Zhan
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Bo Wen
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Bin Tian
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Ke Zheng
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Quancai Li
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Wei Wu
- Laboratory of Printable Functional Materials and Printed Electronics, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
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Lee DH, Lim T, Pyeon J, Park H, Lee SW, Lee S, Kim W, Kim M, Lee JC, Kim DW, Han S, Kim H, Park S, Choi YK. Self-Mixed Biphasic Liquid Metal Composite with Ultra-High Stretchability and Strain-Insensitivity for Neuromorphic Circuits. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310956. [PMID: 38196140 DOI: 10.1002/adma.202310956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/29/2023] [Indexed: 01/11/2024]
Abstract
Neuromorphic circuits that can function under extreme deformations are important for various data-driven wearable and robotic applications. Herein, biphasic liquid metal particle (BMP) with unprecedented stretchability and strain-insensitivity (ΔR/R0 = 1.4@ 1200% strain) is developed to realize a stretchable neuromorphic circuit that mimics a spike-based biologic sensory system. The BMP consists of liquid metal particles (LMPs) and rigid liquid metal particles (RLMPs), which are homogeneously mixed via spontaneous solutal-Marangoni mixing flow during coating. This permits facile single step patterning directly on various substrates at room temperature. BMP is highly conductive (2.3 × 106 S/m) without any post activation steps. BMP interconnects are utilized for a sensory system, which is capable of distinguishing variations of biaxial strains with a spiking neural network, thus demonstrating their potential for various sensing and signal processing applications.
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Affiliation(s)
- Do Hoon Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Taesu Lim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Jeongsu Pyeon
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyunmin Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Sang-Won Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seungkyu Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Wonsik Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Min Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Jeong-Chan Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Do-Wan Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seungmin Han
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyoungsoo Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Steve Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
- KAIST Institute for Health Science and Technology 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Yang-Kyu Choi
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
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Zhu J, Li J, Tong Y, Hu T, Chen Z, Xiao Y, Zhang S, Yang H, Gao M, Pan T, Cheng H, Lin Y. Recent progress in multifunctional, reconfigurable, integrated liquid metal-based stretchable sensors and standalone systems. PROGRESS IN MATERIALS SCIENCE 2024; 142:101228. [PMID: 38745676 PMCID: PMC11090487 DOI: 10.1016/j.pmatsci.2023.101228] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Possessing a unique combination of properties that are traditionally contradictory in other natural or synthetical materials, Ga-based liquid metals (LMs) exhibit low mechanical stiffness and flowability like a liquid, with good electrical and thermal conductivity like metal, as well as good biocompatibility and room-temperature phase transformation. These remarkable properties have paved the way for the development of novel reconfigurable or stretchable electronics and devices. Despite these outstanding properties, the easy oxidation, high surface tension, and low rheological viscosity of LMs have presented formidable challenges in high-resolution patterning. To address this challenge, various surface modifications or additives have been employed to tailor the oxidation state, viscosity, and patterning capability of LMs. One effective approach for LM patterning is breaking down LMs into microparticles known as liquid metal particles (LMPs). This facilitates LM patterning using conventional techniques such as stencil, screening, or inkjet printing. Judiciously formulated photo-curable LMP inks or the introduction of an adhesive seed layer combined with a modified lift-off process further provide the micrometer-level LM patterns. Incorporating porous and adhesive substrates in LM-based electronics allows direct interfacing with the skin for robust and long-term monitoring of physiological signals. Combined with self-healing polymers in the form of substrates or composites, LM-based electronics can provide mechanical-robust devices to heal after damage for working in harsh environments. This review provides the latest advances in LM-based composites, fabrication methods, and their novel and unique applications in stretchable or reconfigurable sensors and resulting integrated systems. It is believed that the advancements in LM-based material preparation and high-resolution techniques have opened up opportunities for customized designs of LM-based stretchable sensors, as well as multifunctional, reconfigurable, highly integrated, and even standalone systems.
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Affiliation(s)
- Jia Zhu
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Jiaying Li
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yao Tong
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Taiqi Hu
- School of Electrical Engineering and Automation, Jiangxi University of Science and Technology, Ganzhou 341000, P. R. China
| | - Ziqi Chen
- School of Physical Sciences, University of Science and Technology of China, Hefei 230026, PR China
| | - Yang Xiao
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Senhao Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Hongbo Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Min Gao
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Taisong Pan
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Huanyu Cheng
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuan Lin
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
- Medico-Engineering Cooperation on Applied Medicine Research Center, University of Electronics Science and Technology of China, Chengdu 610054, China
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Qi J, Yang S, Jiang Y, Cheng J, Wang S, Rao Q, Jiang X. Liquid Metal-Polymer Conductor-Based Conformal Cyborg Devices. Chem Rev 2024; 124:2081-2137. [PMID: 38393351 DOI: 10.1021/acs.chemrev.3c00317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Gallium-based liquid metal (LM) exhibits exceptional properties such as high conductivity and biocompatibility, rendering it highly valuable for the development of conformal bioelectronics. When combined with polymers, liquid metal-polymer conductors (MPC) offer a versatile platform for fabricating conformal cyborg devices, enabling functions such as sensing, restoration, and augmentation within the human body. This review focuses on the synthesis, fabrication, and application of MPC-based cyborg devices. The synthesis of functional materials based on LM and the fabrication techniques for MPC-based devices are elucidated. The review provides a comprehensive overview of MPC-based cyborg devices, encompassing their applications in sensing diverse signals, therapeutic interventions, and augmentation. The objective of this review is to serve as a valuable resource that bridges the gap between the fabrication of MPC-based conformal devices and their potential biomedical applications.
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Affiliation(s)
- Jie Qi
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, the NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong 511436, P. R. China
| | - Shuaijian Yang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Yizhou Jiang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P. R. China
| | - Jinhao Cheng
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Saijie Wang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Qingyan Rao
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Xingyu Jiang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering. Southern University of Science and Technology, No. 1088, Xueyuan Rd, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
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Hou S, Chen C, Bai L, Yu J, Cheng Y, Huang W. Stretchable Electronics with Strain-Resistive Performance. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306749. [PMID: 38078789 DOI: 10.1002/smll.202306749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/15/2023] [Indexed: 03/16/2024]
Abstract
Stretchable electronics have attracted tremendous attention amongst academic and industrial communities due to their prospective applications in personal healthcare, human-activity monitoring, artificial skins, wearable displays, human-machine interfaces, etc. Other than mechanical robustness, stable performances under complex strains in these devices that are not for strain sensing are equally important for practical applications. Here, a comprehensive summarization of recent advances in stretchable electronics with strain-resistive performance is presented. First, detailed overviews of intrinsically strain-resistive stretchable materials, including conductors, semiconductors, and insulators, are given. Then, systematic representations of advanced structures, including helical, serpentine, meshy, wrinkled, and kirigami-based structures, for strain-resistive performance are summarized. Next, stretchable arrays and circuits with strain-resistive performance, that integrate multiple functionalities and enable complex behaviors, are introduced. This review presents a detailed overview of recent progress in stretchable electronics with strain-resistive performances and provides a guideline for the future development of stretchable electronics.
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Affiliation(s)
- Sihui Hou
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Cong Chen
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Libing Bai
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Junsheng Yu
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yuhua Cheng
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Wei Huang
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
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Lu G, Ni E, Jiang Y, Wu W, Li H. Room-Temperature Liquid Metals for Flexible Electronic Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304147. [PMID: 37875665 DOI: 10.1002/smll.202304147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/26/2023] [Indexed: 10/26/2023]
Abstract
Room-temperature gallium-based liquid metals (RT-GaLMs) have garnered significant interest recently owing to their extraordinary combination of fluidity, conductivity, stretchability, self-healing performance, and biocompatibility. They are ideal materials for the manufacture of flexible electronics. By changing the composition and oxidation of RT-GaLMs, physicochemical characteristics of the liquid metal can be adjusted, especially the regulation of rheological, wetting, and adhesion properties. This review highlights the advancements in the liquid metals used in flexible electronics. Meanwhile related characteristics of RT-GaLMs and underlying principles governing their processing and applications for flexible electronics are elucidated. Finally, the diverse applications of RT-GaLMs in self-healing circuits, flexible sensors, energy harvesting devices, and epidermal electronics, are explored. Additionally, the challenges hindering the progress of RT-GaLMs are discussed, while proposing future research directions and potential applications in this emerging field. By presenting a concise and critical analysis, this paper contributes to the advancement of RT-GaLMs as an advanced material applicable for the new generation of flexible electronics.
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Affiliation(s)
- Guixuan Lu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Erli Ni
- The Institute for Advanced Studies of Wuhan University, Wuhan University, Wuhan, Hubei, 430072, China
| | - Yanyan Jiang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Weikang Wu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Hui Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
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10
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Gong S, Lu Y, Yin J, Levin A, Cheng W. Materials-Driven Soft Wearable Bioelectronics for Connected Healthcare. Chem Rev 2024; 124:455-553. [PMID: 38174868 DOI: 10.1021/acs.chemrev.3c00502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
In the era of Internet-of-things, many things can stay connected; however, biological systems, including those necessary for human health, remain unable to stay connected to the global Internet due to the lack of soft conformal biosensors. The fundamental challenge lies in the fact that electronics and biology are distinct and incompatible, as they are based on different materials via different functioning principles. In particular, the human body is soft and curvilinear, yet electronics are typically rigid and planar. Recent advances in materials and materials design have generated tremendous opportunities to design soft wearable bioelectronics, which may bridge the gap, enabling the ultimate dream of connected healthcare for anyone, anytime, and anywhere. We begin with a review of the historical development of healthcare, indicating the significant trend of connected healthcare. This is followed by the focal point of discussion about new materials and materials design, particularly low-dimensional nanomaterials. We summarize material types and their attributes for designing soft bioelectronic sensors; we also cover their synthesis and fabrication methods, including top-down, bottom-up, and their combined approaches. Next, we discuss the wearable energy challenges and progress made to date. In addition to front-end wearable devices, we also describe back-end machine learning algorithms, artificial intelligence, telecommunication, and software. Afterward, we describe the integration of soft wearable bioelectronic systems which have been applied in various testbeds in real-world settings, including laboratories that are preclinical and clinical environments. Finally, we narrate the remaining challenges and opportunities in conjunction with our perspectives.
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Affiliation(s)
- Shu Gong
- Department of Chemical & Biological Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Yan Lu
- Department of Chemical & Biological Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Jialiang Yin
- Department of Chemical & Biological Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Arie Levin
- Department of Chemical & Biological Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Wenlong Cheng
- Department of Chemical & Biological Engineering, Monash University, Clayton, Victoria 3800, Australia
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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: 0] [Impact Index Per Article: 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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12
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Liu J, Zeng S, Zhang M, Xiong J, Gu H, Wang Z, Hu Y, Zhang X, Du Y, Ren L. Giant Piezoelectric Output and Stability Enhancement in Piezopolymer Composites with Liquid Metal Nanofillers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2304096. [PMID: 37705125 PMCID: PMC10754131 DOI: 10.1002/advs.202304096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Indexed: 09/15/2023]
Abstract
Integrating nanomaterials into the polymer matrix is an effective strategy to optimize the performance of polymer-based piezoelectric devices. Nevertheless, the trade-off between the output enhancement and stability maintenance of piezoelectric composites usually leads to an unsatisfied overall performance for the high-strength operation of devices. Here, by setting liquid metal (LM) nanodroplets as the nanofillers in a poly(vinylidene difluoride) (PVDF) matrix, the as-formed liquid-solid/conductive-dielectric interfaces significantly promote the piezoelectric output and the reliability of this piezoelectric composite. A giant performance improvement featured is obtained with, nearly 1000% boosting on the output voltage (as high as 212 V), 270% increment on the piezoelectric coefficient (d33 ∼51.1 pC N-1 ) and long-term reliability on both structure and output (over 36 000 cycles). The design of a novel heterogenous interface with both mechanical matching and electric coupling can be the new orientation for developing high performance piezoelectric composite-based devices.
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Affiliation(s)
- Jingyan Liu
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Shi Zeng
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Mingrui Zhang
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Juan Xiong
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Haoshuang Gu
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Zhao Wang
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Yongming Hu
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Xianghui Zhang
- Hubei Key Laboratory of Ferro & Piezoelectric Materials and DevicesSchool of MicroelectronicsHubei UniversityWuhan430062P. R. China
| | - Yi Du
- Center of Quantum and Matter Science and School of PhysicsBeihang UniversityBeijing100191P. R. China
| | - Long Ren
- State Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingInternational School of Materials Science and EngineeringWuhan University of TechnologyWuhan430070P. R. China
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13
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Zhou J, Zhao S, Tang L, Zhang D, Sheng B. Programmable and Weldable Superelastic EGaIn/TPU Composite Fiber by Wet Spinning for Flexible Electronics. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 38031357 DOI: 10.1021/acsami.3c11068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
As an essential component of flexible electronics, superelastic conductive fibers with good mechanical and electrical properties have drawn significant attention, especially in their preparation. In this study, we prepared a superelastic conductive fiber composed of eutectic gallium-indium (EGaIn) and thermoplastic polyurethane (TPU) by simple wet spinning. The composite conductive fiber with a liquid metal (LM) content of 85 wt % achieved a maximum strain at a break of 659.2%, and after the conductive pathway in the porous structure of the composite fibers was fully activated, high conductivity (1.2 × 105 S/m) was achieved with 95 wt % LM by mechanical sintering and training processes. The prepared conductive fibers exhibited a stable resistive response as the fibers were strained and could be sewn into fabrics and used as wearable strain sensors to monitor various human motions. These conductive fibers can be molded into helical by heating, and they have excellent electrical properties at a maximum mechanical strain of 3400% (resistance change <0.27%) with a helical index of 11. Moreover, the conductive fibers can be welded to various two or three-dimensional conductors. In summary, with a scalable manufacturing process, weldability, superelasticity, and high electrical conductivity, EGaIn/TPU composite fibers fabricated by wet spinning have considerable potential for flexible electronics.
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Affiliation(s)
- Jingyu Zhou
- School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Shanshan Zhao
- School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Lei Tang
- School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Dawei Zhang
- School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Bin Sheng
- School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
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Zhu T, Wu K, Wang Y, Zhang J, Liu G, Sun J. Highly stable and strain-insensitive metal film conductors via manipulating strain distribution. MATERIALS HORIZONS 2023; 10:5920-5930. [PMID: 37873924 DOI: 10.1039/d3mh01399e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Metal film-based stretchable conductors are essential elements of flexible electronics for wearable, biomedical, and robotic applications, which require strain-insensitive high conductivity over a wide strain range and excellent cyclic stability. However, they suffer from serious electrical failure under monotonic and cyclic tensile loading at a small strain due to the uncontrolled film cracking behavior. Here, we propose a novel in-plane crack control strategy of engineering hierarchical microstructures to achieve outstanding electromechanical performance via harnessing the strain distribution in metal films. The wrinkles delay the crack initiation at undercuts which should be the most vulnerable sites during the stretching process. The surface protrusions/grooves/undercuts inhibit the crack propagation because of the effective strain redistribution. In addition, hierarchical microstructures significantly improve cyclic stability due to the strong interfacial adhesion and stable crack patterns. The metal film-based conductors exhibit ultrahigh strain-insensitive conductivity (1.7 × 107 S m-1), negligible resistance change (ΔR/R0 = 0.007) over an ultra-wide strain range (>200%), and excellent cyclic strain durability (>15 000 cycles at 100% strain). A range of metal films was explored to establish the universality of this strategy, including ductile copper and silver, as well as brittle molybdenum and high entropy alloy. We demonstrate the strain-insensitive electrical functionality of a metal film-based conductor in a flexible light-emitting diode circuit.
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Affiliation(s)
- Ting Zhu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Kai Wu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Yaqiang Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Jinyu Zhang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Gang Liu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Jun Sun
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
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15
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Ai L, Lin W, Cao C, Li P, Wang X, Lv D, Li X, Yang Z, Yao X. Tough soldering for stretchable electronics by small-molecule modulated interfacial assemblies. Nat Commun 2023; 14:7723. [PMID: 38001116 PMCID: PMC10673831 DOI: 10.1038/s41467-023-43574-8] [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: 05/05/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
The rapid-developing soft robots and wearable devices require flexible conductive materials to maintain electric functions over a large range of deformations. Considerable efforts are made to develop stretchable conductive materials; little attention is paid to the frequent failures of integrated circuits caused by the interface mismatch of soft substrates and rigid silicon-based microelectronics. Here, we present a stretchable solder with good weldability that can strongly bond with electronic components, benefiting from the hierarchical assemblies of liquid metal particles, small-molecule modulators, and non-covalently crosslinked polymer matrix. Our self-solder shows high conductivity (>2×105 S m-1), extreme stretchability (~1000%, and >600% with chip-integrated), and high toughness (~20 MJ m-3). Additionally, the dynamic interactions within our solder's surface and interior enable a range of unique features, including ease of integration, component substitution, and circuit recyclability. With all these features, we demonstrated an application as thermoforming technology for three-dimensional (3D) conformable electronics, showing potential in reducing the complexity of microchip interfacing, as well as scalable fabrication of chip-integrated stretchable circuits and 3D electronics.
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Affiliation(s)
- Liqing Ai
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China
| | - Weikang Lin
- Department of Mechanical & Aerospace Engineering, Hong Kong University of Science and Technology, Hong Kong, 999077, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Chunyan Cao
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China
| | - Pengyu Li
- Department of Mechanical & Aerospace Engineering, Hong Kong University of Science and Technology, Hong Kong, 999077, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Xuejiao Wang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China
| | - Dong Lv
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China
| | - Xin Li
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China
| | - Zhengbao Yang
- Department of Mechanical & Aerospace Engineering, Hong Kong University of Science and Technology, Hong Kong, 999077, China.
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China.
| | - Xi Yao
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, 999077, China.
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518000, China.
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Aftab S, Hussain S, Al-Kahtani AA. Latest Innovations in 2D Flexible Nanoelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2301280. [PMID: 37104492 DOI: 10.1002/adma.202301280] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/30/2023] [Indexed: 06/19/2023]
Abstract
2D materials with dangling-bond-free surfaces and atomically thin layers have been shown to be capable of being incorporated into flexible electronic devices. The electronic and optical properties of 2D materials can be tuned or controlled in other ways by using the intriguing strain engineering method. The latest and encouraging techniques in regard to creating flexible 2D nanoelectronics are condensed in this review. These techniques have the potential to be used in a wider range of applications in the near and long term. It is possible to use ultrathin 2D materials (graphene, BP, WTe2 , VSe2 etc.) and 2D transition metal dichalcogenides (2D TMDs) in order to enable the electrical behavior of the devices to be studied. A category of materials is produced on smaller scales by exfoliating bulk materials, whereas chemical vapor deposition (CVD) and epitaxial growth are employed on larger scales. This overview highlights two distinct requirements, which include from a single semiconductor or with van der Waals heterostructures of various nanomaterials. They include where strain must be avoided and where it is required, such as solutions to produce strain-insensitive devices, and such as pressure-sensitive outcomes, respectively. Finally, points-of-view about the current difficulties and possibilities in regard to using 2D materials in flexible electronics are provided.
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Affiliation(s)
- Sikandar Aftab
- Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, 05006, South Korea
| | - Sajjad Hussain
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul, 05006, South Korea
| | - Abdullah A Al-Kahtani
- Chemistry Department, Collage of Science, King Saud University, P. O. Box 2455, Riyadh, 11451, Saudi Arabia
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Jeong S, Oh J, Kim H, Bae J, Ko SH. Pattern design of a liquid metal-based wearable heater for constant heat generation under biaxial strain. iScience 2023; 26:107008. [PMID: 37332675 PMCID: PMC10275728 DOI: 10.1016/j.isci.2023.107008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/05/2023] [Accepted: 05/26/2023] [Indexed: 06/20/2023] Open
Abstract
As the wearable heater is increasingly popular due to its versatile applications, there is a growing need to improve the tensile stability of the wearable heater. However, maintaining the stability and precise control of heating in resistive heaters for wearable electronics remains challenging due to multiaxial dynamic deformation with human motion. Here, we propose a pattern study for a circuit control system without complex structure or deep learning of the liquid metal (LM)-based wearable heater. The LM direct ink writing (DIW) method was used to fabricate the wearable heaters in various designs. Through the study about the pattern, the significance of input power per unit area for steady average temperature with tension was proven, and the directionality of the pattern was shown to be a factor that makes feedback control difficult due to the difference in resistance change according to strain direction. For this issue, a wearable heater with the same minimal resistance change regardless of the tension direction was developed using Peano curves and sinuous pattern structure. Lastly, by attaching to a human body model, the wearable heater with the circuit control system shows stable heating (52.64°C, with a standard deviation of 0.91°C) in actual motion.
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Affiliation(s)
- Seongmin Jeong
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
| | - Jinhyeok Oh
- Bio-Robotics and Control Lab, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulsan 44919, Korea
| | - Hongchan Kim
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
| | - Joonbum Bae
- Bio-Robotics and Control Lab, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulsan 44919, Korea
| | - Seung Hwan Ko
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
- Institute of Engineering Research/Institute of Advanced Machinery and Design (SNU-IAMD), Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
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