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Lu J, Zhu G, Wang S, Wu C, Qu X, Dong X, Pang H, Zhang Y. 3D Printed MXene-Based Wire Strain Sensors with Enhanced Sensitivity and Anisotropy. Small 2024:e2401565. [PMID: 38745539 DOI: 10.1002/smll.202401565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/28/2024] [Indexed: 05/16/2024]
Abstract
Stretchable strain sensors play a crucial role in intelligent wearable systems, serving as the interface between humans and environment by translating mechanical strains into electrical signals. Traditional fiber strain sensors with intrinsic uniform axial strain distribution face challenges in achieving high sensitivity and anisotropy. Moreover, existing micro/nano-structure designs often compromise stretchability and durability. To address these challenges, a novel approach of using 3D printing to fabricate MXene-based flexible sensors with tunable micro and macrostructures. Poly(tetrafluoroethylene) (PTFE) as a pore-inducing agent is added into 3D printable inks to achieve controllable microstructural modifications. In addition to microstructure tuning, 3D printing is employed for macrostructural design modifications, guided by finite element modeling (FEM) simulations. As a result, the 3D printed sensors exhibit heightened sensitivity and anisotropy, making them suitable for tracking static and dynamic displacement changes. The proposed approach presents an efficient and economically viable solution for standardized large-scale production of advanced wire strain sensors.
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Affiliation(s)
- Jingqi Lu
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing, 210044, P. R. China
| | - Guoyin Zhu
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing, 210044, P. R. China
| | - Shaolong Wang
- State Key Laboratory of Organic Electronics and Information Displays Institute of Advanced Materials (IAM) School of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, P. R. China
| | - Chunjin Wu
- State Key Laboratory of Organic Electronics and Information Displays Institute of Advanced Materials (IAM) School of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, P. R. China
| | - Xinyu Qu
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Xiaochen Dong
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Huan Pang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu, 225009, P. R. China
| | - Yizhou Zhang
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing, 210044, P. R. China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Abstract
Metal film-based stretchable strain sensors hold great promise for applications in various domains, which require superior sensitivity-stretchability-cyclic stability synergy. However, the sensitivity-stretchability trade-off has been a long-standing dilemma and the metal film-based strain sensors usually suffer from weak cyclic durability, both of which significantly limit their practical applications. Here, we propose an extremely facile, low-cost and spontaneous strategy that incorporates topological gradients in metal film-based strain sensors, composed of intrinsic (grain size and interface) and extrinsic (film thickness and wrinkle) microstructures. The topological gradient strain sensor exhibits an ultrawide stretchability of 100% while simultaneously maintaining a high sensitivity at an optimal topological gradient of 4.5, due to the topological gradients-induced multistage film cracking. Additionally, it possesses a decent cyclic stability for >10 000 cycles between 0 and 40% strain enabled by the gradient-mixed metal/elastomer interfaces. It can monitor the full-range human activities from subtle pulse signals to vigorous joint movements.
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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
| | - Yun Xia
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - Chao Yang
- School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, P.R. China
| | - Jiaorui Chen
- 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
| | - Xiong Pu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 101400, 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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4
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Kong M, You I, Lee G, Park G, Kim J, Park D, Jeong U. Transparent Omni-Directional Stretchable Circuit Lines Made by a Junction-Free Grid of Expandable Au Lines. Adv Mater 2021; 33:e2100299. [PMID: 34155682 DOI: 10.1002/adma.202100299] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/21/2021] [Indexed: 06/13/2023]
Abstract
Although various stretchable optoelectronic devices have been reported, omni-directionally stretchable transparent circuit lines have been a great challenge. Cracks are engineered and fabricated to be highly conductive patterned metal circuit lines in which gold (Au) grids are embedded. Au is deposited selectively in the cracks to form a grid without any junction between the grid lines. Since each grid line is expandable under stretching, the circuit lines are stretchable in all the directions. This study shows that a thin coating of aluminum on the oxide surface enables precise control of the cracks (crack density, crack depth) in the oxide layer. High optical transparency and high stretchability can be achieved simultaneously by controlling the grid density in the circuit line. Light-emitting diodes are integrated directly on the circuit lines and stable operation is demonstrated under 100% stretching.
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Affiliation(s)
- Minsik Kong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Insang You
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Gilwoon Lee
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Gyeongbae Park
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Jaehyun Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Doowon Park
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam, Pohang, 37673, Republic of Korea
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Kim T, Kim D, Yoon J, Joo Y, Hong Y. Stamp-Perforation-Inspired Micronotch for Selectively Tearing Fiber-Bridged Carbon Nanotube Thin Films and Its Applications for Strain Classification. ACS Appl Mater Interfaces 2021; 13:32307-32315. [PMID: 34181397 DOI: 10.1021/acsami.1c08590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cracks typically deteriorate the structural and electrical properties of materials when not properly controlled. A few papers recently reported the controlling methods of crack formation in the brittle materials utilizing the lateral V-notch structure. For ductile materials, however, there have been few papers reporting cracking phenomenon, but full cracking control including predesigned initiation, propagation, and termination has not been reported yet. Therefore, we report a predesigned full cracking control in ductile conductive carbon nanotube (CNT) films by introducing inkjet-printed L-shape micronotch (LMN) structures inspired by directional stamp perforation marks. In spite of the high fracture toughness of CNT films, the LMNs determine locations of initial crack formation and guide crack propagation in a predesigned way. Selective connection of isolated cracks in the CNT film increases its resistance monotonically under tensile strain and thus tremendously well maintains high linearity (adj. R2 value > 0.99) in resistance change over record large strain ranges of 0.01-100%, which enables us to quantitatively classify strain values accurately for previously reported practical body signals for the first time. We believe that our facile printing-based crack control strategy not only provides a comprehensive solution to various stretchable sensor applications but also builds a new milestone for cracking mechanism studies in fracture mechanics.
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Affiliation(s)
- Taehoon Kim
- Department of Electrical and Computer Engineering and Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Daesik Kim
- Department of Electrical and Computer Engineering and Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Jaeyoung Yoon
- Department of Electrical and Computer Engineering and Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Yunsik Joo
- Department of Electrical and Computer Engineering and Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Yongtaek Hong
- Department of Electrical and Computer Engineering and Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
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Abstract
Stretchable electronics has emerged over the past decade and is now expected to bring form factor-free innovation in the next-generation electronic devices. Stretchable devices have evolved with the synthesis of new soft materials and new device architectures that require significant deformability while maintaining the high device performance of the conventional rigid devices. As the mismatch in the mechanical stiffness between materials, layers, and device units is the major challenge for stretchable electronics, interface control in varying scales determines the device characteristics and the level of stretchability. This article reviews the recent advances in interface control for stretchable electronic devices. It summarizes the design principles and covers the representative approaches for solving the technological issues related to interfaces at different scales: i) nano- and microscale interfaces between materials, ii) mesoscale interfaces between layers or microstructures, and iii) macroscale interfaces between unit devices, substrates, or electrical connections. The last section discusses the current issues and future challenges of the interfaces for stretchable devices.
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Affiliation(s)
- Dong Wook Kim
- Department of Materials Science and EngineeringPohang University of Science and Technology (POSTECH)77 Cheongam‐Ro, Nam‐GuPohangGyeongbuk37673Republic of Korea
| | - Minsik Kong
- Department of Materials Science and EngineeringPohang University of Science and Technology (POSTECH)77 Cheongam‐Ro, Nam‐GuPohangGyeongbuk37673Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and EngineeringPohang University of Science and Technology (POSTECH)77 Cheongam‐Ro, Nam‐GuPohangGyeongbuk37673Republic of Korea
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7
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Wu C, Wang H, Li Y, Kim T, Kwon SJ, Park B, He Z, Lee SB, Um MK, Byun JH, Chou TW. Sensitivity Improvement of Stretchable Strain Sensors by the Internal and External Structural Designs for Strain Redistribution. ACS Appl Mater Interfaces 2020; 12:50803-50811. [PMID: 33135419 DOI: 10.1021/acsami.0c13427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fiber strain sensors that are directly woven into smart textiles play an important role in wearable systems. These sensors require a high sensitivity to detect the subtle strain in practical applications. However, traditional fiber strain sensors with constant diameters undergo homogeneous strain distribution in the axial direction, thereby limiting the sensitivity improvement. Herein, a novel strategy of internal or external structural design is proposed to significantly improve the sensitivity of fiber strain sensors. The fibers are produced with directional increases in diameter (internal design) or polydimethylsiloxane (PDMS) microbeads attached to surfaces (external design) by combining hollow glass tubes used as templates with PDMS drops. The structural modification of the fiber significantly impacts the sensing performance. After optimizing structural parameters, the highest gauge factor reaches 123.1 in the internal-external structure design at 25% strain. A comprehensive analysis reveals that the desirable scheme is the internal structural design, which features a high sensitivity of 110 with a 100% improvement at ∼5-20% strain. Because of the sufficiently robust interface, even at the 800th cycle, fiber sensors still possessed an excellent stable performance. The morphology evolution mechanism indicates that the resistance increase is closely related with the increased peak width and distance, and the appearance of gaps. Based on the finite element modeling simulation, the quantified effective contributions of different strategies positively correlate with the improved sensitivity. The proposed fiber strain sensors, which are woven into the two-dimensional network structure, exhibit an excellent capability for displacement monitoring and facilitate the traffic control of crossroads.
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Affiliation(s)
- Chunjin Wu
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Huai Wang
- Materials Processing Innovation Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Ying Li
- School of Material Science & Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Taehoon Kim
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Suk Jin Kwon
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Byeongjin Park
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Zuoli He
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, P. R. China
| | - Sang-Bok Lee
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Moon-Kwang Um
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Joon-Hyung Byun
- Composites Research Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 51508, South Korea
| | - Tsu-Wei Chou
- Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716, United States
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Ramírez J, Polat B, Lipomi DJ. Metallic Nanoislands on Graphene for Biomechanical Sensing. ACS Omega 2020; 5:15763-15770. [PMID: 32656394 PMCID: PMC7345399 DOI: 10.1021/acsomega.0c01967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
This minireview describes a nanomaterial-based multimodal sensor for performing biomechanical measurements. The sensor consists of ultrathin metallic films on single-layer graphene. This composite material exhibits physical properties that neither material possesses alone. For example, the metal, deposited by evaporation at low (≤10 nm) nominal thicknesses, renders the film highly sensitive to mechanical stimuli, which can be detected using electrical (i.e., resistance) and optical (i.e., plasmonic) modalities. The electrical modality, in particular, is capable of resolving deformations as small as 0.0001% engineering strain, or 1 ppm. The electrical and optical responses of the composite films can be tailored by controlling the morphology of the metallic film. This morphology (granular or island-like when deposited onto the graphene) can be tuned using the conditions of deposition, the identity of the substrate beneath the graphene, or even the replacement of the graphene for hexagonal boron nitride (hBN). This material responds to forces produced by a range of physiological structures, from the contractions of heart muscle cells, to the beating of the heart through the skin, to stretching of the skin due to the expansion of the lungs and movement of limbs. Here, we provide an update on recent applications of this material in fields ranging from cardiovascular medicine (by measuring the contractions of 2D monolayers of cardiomyocytes), regenerative medicine (optical measurements of the forces produced by myoblasts), speech pathology and physical therapy (measuring swallowing function in head and neck cancer survivors), lab-on-a-chip devices (using deformation of sidewalls of microfluidic channels to detect transiting objects), and sleep medicine (measuring pulse and respiration with a wearable, unobtrusive device). We also discuss the mechanisms by which these films detect strain.
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Affiliation(s)
- Julian Ramírez
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States
| | - Beril Polat
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States
| | - Darren J. Lipomi
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States
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Seo KW, Cho C, Jang HI, Park JH, Lee JY. Enhanced bendability of nanostructured metal electrodes: effect of nanoholes and their arrangement. Nanoscale 2020; 12:12898-12908. [PMID: 32520068 DOI: 10.1039/d0nr00316f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Metallic thin films often exhibit poor mechanical robustness, which makes them unsuitable for use as electrodes in flexible and stretchable electronic devices. This prompted us to investigate the effect of creating a pattern of nanoholes in a metallic thin film to its mechanical and electrical properties. The adoption of nanonetwork structures is shown to confer significantly improved bendability to the films, with a change in electrical resistance of only 21% after 10 000 bending cycles, under a bending strain of 6.3%. In contrast to the planar silver (Ag) films in which large cracks are formed, structures that contain nanoholes act as barriers that block the growth of cracks; consequently, only short cracks are formed in these films and therefore changes in their resistance are much lower. In this paper, we suggest a novel model based on random grain boundaries to simulate the behavior of various nanopattern arrangements when the film is subjected to mechanical stress. Our modeling studies revealed that nanoholes secure the electrical current pathways by effectively blocking crack propagation, and that optimizing orientation, size, and coverage of these nanoholes can further improve the mechanical properties. Although diamond patterns exhibit superior characteristics to those of rectangular ones, their directional dependence is shown to be reduced by adopting randomly dispersed nanostructures. We additionally verified experimentally that an array of holes (rectangular, diamond-shaped, and randomly patterned) significantly affects crack propagation and resistance change.
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Affiliation(s)
- Ki-Won Seo
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
| | - Changsoon Cho
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea. and Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) Technische Universität Dresden, Nöthnitzer Straße 61, Dresden 01187, Germany
| | - Hyun-Ik Jang
- Department of Research, NanoIn Inc., Daejeon 34166, Republic of Korea
| | - Jae Hong Park
- Department of Research, NanoIn Inc., Daejeon 34166, Republic of Korea
| | - Jung-Yong Lee
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea. and Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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Sun F, Tian M, Sun X, Xu T, Liu X, Zhu S, Zhang X, Qu L. Stretchable Conductive Fibers of Ultrahigh Tensile Strain and Stable Conductance Enabled by a Worm-Shaped Graphene Microlayer. Nano Lett 2019; 19:6592-6599. [PMID: 31434486 DOI: 10.1021/acs.nanolett.9b02862] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Stretchable electrical conductors have demonstrated promising potentials in a wide range of wearable electronic devices, but the conductivity of most reported stretchable conductive fibers will be changed if be stretched or strained. Stable conductance is essential for wearable and stretchable devices, to ensure the performance is stable. Inspired by the peristaltic behavior of arthropods, we designed a graphene coating similar to the caterpillar structure on the polyurethane (PU) fiber surface, enabled by coating the worm-shaped graphene microlayer onto polyurethane filaments. Such worm-shaped filaments can be stretched up to 1010% with a wide reversible electroresponse range (0 < ε < 815%), long-term durability (>4000 stretching/releasing cycles), good initial conductivity (σ0 = 124 S m-1), and high quality factor (Q = 11.26). Remarkably, the worm-shaped filaments show distinctive strain-insensitive behavior (ΔR/R0 < 0.1) up to 220% strain. Furthermore, the filaments as electrical circuits of light emitting diodes (LEDs) to track signals from robust human joint movements are also demonstrated for practical application. Such worm-shaped filaments with distinctive strain-insensitive behavior provide a direct pathway for stretchy electronics.
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Affiliation(s)
- Fengqiang Sun
- Research Center for Intelligent and Wearable Technology, College of Textiles and Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Collaborative Innovation Center for Eco-Textiles of Shandong Province , Qingdao University , Qingdao , Shandong 266071 , P.R. China
| | - Mingwei Tian
- Research Center for Intelligent and Wearable Technology, College of Textiles and Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Collaborative Innovation Center for Eco-Textiles of Shandong Province , Qingdao University , Qingdao , Shandong 266071 , P.R. China
| | - Xuantong Sun
- School of Materials , The University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Tailin Xu
- Research Center for Bioengineering and Sensing Technology , University of Science and Technology Beijing , 30 Xueyuan Road , Beijing 100083 , P. R. China
| | - Xuqing Liu
- School of Materials , The University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Shifeng Zhu
- Research Center for Intelligent and Wearable Technology, College of Textiles and Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Collaborative Innovation Center for Eco-Textiles of Shandong Province , Qingdao University , Qingdao , Shandong 266071 , P.R. China
| | - Xueji Zhang
- School of Biomedical Engineering , Shenzhen University Health Science Center , Shenzhen , Guangdong 518060 , P.R.China
| | - Lijun Qu
- Research Center for Intelligent and Wearable Technology, College of Textiles and Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Collaborative Innovation Center for Eco-Textiles of Shandong Province , Qingdao University , Qingdao , Shandong 266071 , P.R. China
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Roh H, Cho S, Lee G, Moon S, Kong M, You I, Jeong U. Liquid Metal Covered with Thermoplastic Conductive Composites for High Electrical Stability and Negligible Electromechanical Coupling at Large Strains. ACS Appl Mater Interfaces 2019; 11:26204-26212. [PMID: 31259517 DOI: 10.1021/acsami.9b08648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Stretchable electrode is an essential part of soft electronic devices. Practical stretchable electrodes must meet the following requirements: metallic conductivity and no resistance change in various situations such as repeated large deformation, toxic environment, and large temperature change. This study suggests a simple electrode design that meets all of these requirements simultaneously. The electrode consists of a liquid metal (LM) mesh pattern that is sandwiched between a thermoplastic block copolymer (BCP) film and a BCP/Ag flake composite film with a microfibril network structure on its surface. The electrode has a high conductivity (1.2 × 104 S/cm) and is stretchable up to 600% uniaxial strain (ε). Its resistance remains unchanged during repeated stretching cycles at ε = 300% (ΔR < 0.04 Ω) as well as under simultaneous situation of large deformation (ε = 400%) and large temperature change (20-70 °C). The electrode is anticorrosive in an acidic solution owing to the hydrophobic BCP layer that protects the LM from being etched. This study shows the connection of two separate electrodes and complete healing of scratched electrodes by finger pressing. In addition, it demonstrates the fabrication of superstretchable electroluminescence display as an example of potential uses of the electrode.
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Affiliation(s)
- Heejung Roh
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
| | - Sunghwan Cho
- Department of Materials Science and Engineering , Yonsei University , 50, Yonsei-ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Gilwoon Lee
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
| | - Sungmin Moon
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
| | - Minsik Kong
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
| | - Insang You
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Cheongam-ro , Nam-gu, Pohang-si , Gyeongsangbuk-do 37673 , Republic of Korea
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Abstract
As industrial needs for healthcare sensors, electronic skin, and flexible/stretchable displays increase, interest in stretchable materials is increasing as well. In recent years, the studies on stretchable materials have spread to various pivot components, such as electrodes, circuits, substrates, semiconductors, dielectric layers, membranes, and active nanocomposite films. The block copolymer (BC) elastomers have been playing considerable role in the development of stretchable materials. Since BCs are soft elastomers based on physical cross-links, they show differences in physical properties from normal elastomers formed with chemical cross-linking. BC elastomers does not require additional chemical cross-linking procedure, so they can be easily processed after dissolved in various solvents. Their viscoelasticity and thermoplasticity enable the BCs to become moldable and sticky. Although their unique physical properties may serve as disadvantages in some cases, they have been actively applied to create various stretchable electronic materials and their uses are expected to be enlarged more than ever. In this Account, we summarize recent successful applications of BCs for the stretchable electronic devices and discuss the possibility of further uses and the challenges to be addressed for practical uses. Studies on BC-based stretchable materials have focused initially on the fabrication process of stretchable conductors; mixing conductive fillers physically with BCs, infiltrating BCs in a conductive filler layer, and converting metal precursors into metal nanoparticles inside BCs. When conductive fillers with high aspect ratios, such as nanowires or nanosheets are used, the fillers can be infiltrated by the BCs after deposited. Since the contacts between the fillers are maintained during the infiltration process, even thin composite films possess high conductivity and stretchability. The metal precursor solution printing is suggested as a promising approach because it is compatible with traditional printing techniques without clogging the nozzles and allows high filler loading efficiency. When using a BC as a substrate, it is advisable to use a BC/PDMS double layer because of viscoelastic and thermoplastic properties of BCs. If BC/PDMS double layer is used with much thicker PDMS layer instead of viscoelastic BC alone, the double layer substrate can show a perfect elastomeric behavior, and the advantages of the BC substrate are preserved. Additionally, the use of conventional manufacturing techniques is important for commercialization of the stretchable devices. BC substrates having preformed microfibril network on their surfaces facilitate the fabrication of high-resolution circuitry by directly depositing metals through a mask on the substrate. Recent successes of fabricating stretchable organic transistors were obtained based on in situ phase separation of polymer semiconductors to form nanofibril bundles on the surface of a BC substrate. They have led to the achievement of high resolution transistor array printed in large area. BCs are expected to expand their applicability, including stretchable batteries, since they make it feasible to fabricate various hybrid nanocomposites, pore size-controlled membranes, and microstructured surfaces. However, it is necessary to secure long-term stability under heat, solvent, and UV; in addition, there is a need for the synthesis of functional BCs for use in stretchable implanted biomedical devices.
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Affiliation(s)
- Insang You
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
| | - Minsik Kong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
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Oh S, Kim J, Chang ST. Highly sensitive metal-grid strain sensors via water-based solution processing. RSC Adv 2018; 8:42153-42159. [PMID: 35558796 PMCID: PMC9092150 DOI: 10.1039/c8ra08721k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 12/06/2018] [Indexed: 11/21/2022] Open
Abstract
Strain sensor technologies have been spotlighted for their versatility for healthcare, soft robot, and human–robot applications. Expecting large future demands for such technology, extensive studies have investigated flexible and stretchable strain sensors based on various nanomaterials and metal films. However, it is still challenging to simultaneously satisfy parameters such as sensitivity, stretchability, linearity, hysteresis, and mass producibility. In this work, we demonstrate a novel approach for producing highly sensitive metal-grid strain sensors based on an all-solution process, which is suitable for mass production. We investigated the effects of the width of the metal grid and width/spacing ratio on the piezoresistivity of the strain sensors. The metal grid strain sensors exhibited high sensitivity (gauge factor of 4685.9 at 5% strain), rapid response time (∼18.6 ms), and superior strain range (≤5%) compared to other metal-based sensors. We demonstrated that the sensors could successfully convert voice signals and tiny movements of fingers and muscles into electrical signals. In addition, the metal-grid strain sensors were produced using a low-cost procedure without toxic solvent via an all water-based solution process, which is expected to allow the integration of such metal-grid strain sensors into future highly sensitive physical sensing devices. Highly sensitive strain sensors with metal-grid structures formed by a water-based solution process are presented.![]()
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Affiliation(s)
- Seungwoo Oh
- School of Chemical Engineering and Materials Science
- Chung-Ang University
- Seoul 06974
- Republic of Korea
| | - Jin Kim
- School of Chemical Engineering and Materials Science
- Chung-Ang University
- Seoul 06974
- Republic of Korea
| | - Suk Tai Chang
- School of Chemical Engineering and Materials Science
- Chung-Ang University
- Seoul 06974
- Republic of Korea
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