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Pyun KR, Kwon K, Yoo MJ, Kim KK, Gong D, Yeo WH, Han S, Ko SH. Machine-learned wearable sensors for real-time hand-motion recognition: toward practical applications. Natl Sci Rev 2024; 11:nwad298. [PMID: 38213520 PMCID: PMC10776364 DOI: 10.1093/nsr/nwad298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/23/2023] [Accepted: 11/01/2023] [Indexed: 01/13/2024] Open
Abstract
Soft electromechanical sensors have led to a new paradigm of electronic devices for novel motion-based wearable applications in our daily lives. However, the vast amount of random and unidentified signals generated by complex body motions has hindered the precise recognition and practical application of this technology. Recent advancements in artificial-intelligence technology have enabled significant strides in extracting features from massive and intricate data sets, thereby presenting a breakthrough in utilizing wearable sensors for practical applications. Beyond traditional machine-learning techniques for classifying simple gestures, advanced machine-learning algorithms have been developed to handle more complex and nuanced motion-based tasks with restricted training data sets. Machine-learning techniques have improved the ability to perceive, and thus machine-learned wearable soft sensors have enabled accurate and rapid human-gesture recognition, providing real-time feedback to users. This forms a crucial component of future wearable electronics, contributing to a robust human-machine interface. In this review, we provide a comprehensive summary covering materials, structures and machine-learning algorithms for hand-gesture recognition and possible practical applications through machine-learned wearable electromechanical sensors.
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Affiliation(s)
- Kyung Rok Pyun
- Department of Mechanical Engineering, Seoul National University, Seoul08826, South Korea
| | - Kangkyu Kwon
- Department of Mechanical Engineering, Seoul National University, Seoul08826, South Korea
- IEN Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA30332, USA
| | - Myung Jin Yoo
- Department of Mechanical Engineering, Seoul National University, Seoul08826, South Korea
| | - Kyun Kyu Kim
- Department of Chemical Engineering, Stanford University, Stanford, CA94305, USA
| | - Dohyeon Gong
- Department of Mechanical Engineering, Ajou University, Suwon-si16499, South Korea
| | - Woon-Hong Yeo
- IEN Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA30332, USA
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA30332, USA
| | - Seungyong Han
- Department of Mechanical Engineering, Ajou University, Suwon-si16499, South Korea
| | - Seung Hwan Ko
- Department of Mechanical Engineering, Seoul National University, Seoul08826, South Korea
- Institute of Advanced Machinery and Design (SNU-IAMD), Seoul National University, Seoul08826, South Korea
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Hassan MS, Zaman S, Dantzler JZR, Leyva DH, Mahmud MS, Ramirez JM, Gomez SG, Lin Y. 3D Printed Integrated Sensors: From Fabrication to Applications-A Review. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:3148. [PMID: 38133045 PMCID: PMC10745374 DOI: 10.3390/nano13243148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/08/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023]
Abstract
The integration of 3D printed sensors into hosting structures has become a growing area of research due to simplified assembly procedures, reduced system complexity, and lower fabrication cost. Embedding 3D printed sensors into structures or bonding the sensors on surfaces are the two techniques for the integration of sensors. This review extensively discusses the fabrication of sensors through different additive manufacturing techniques. Various additive manufacturing techniques dedicated to manufacture sensors as well as their integration techniques during the manufacturing process will be discussed. This review will also discuss the basic sensing mechanisms of integrated sensors and their applications. It has been proven that integrating 3D printed sensors into infrastructures can open new possibilities for research and development in additive manufacturing and sensor materials for smart goods and the Internet of Things.
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Affiliation(s)
- Md Sahid Hassan
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Saqlain Zaman
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Joshua Z. R. Dantzler
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Diana Hazel Leyva
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Md Shahjahan Mahmud
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Jean Montes Ramirez
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Sofia Gabriela Gomez
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Yirong Lin
- Department of Aerospace and Mechanical Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA; (S.Z.); (J.Z.R.D.); (D.H.L.); (M.S.M.); (J.M.R.); (S.G.G.)
- Aerospace Center, The University of Texas at El Paso, El Paso, TX 79968, USA
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Raj R, Dixit AR. Direct Ink Writing of Carbon-Doped Polymeric Composite Ink: A Review on Its Requirements and Applications. 3D PRINTING AND ADDITIVE MANUFACTURING 2023; 10:828-854. [PMID: 37609584 PMCID: PMC10440670 DOI: 10.1089/3dp.2021.0209] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Direct Ink Writing (DIW) opens new possibilities in three-dimensional (3D) printing of carbon-based polymeric ink. This is due to its ability in design flexibility, structural complexity, and environmental sustainability. This area requires exhaustive study because of its wide application in different manufacturing sectors. The present article is related to the variant emerging 3D printing techniques and DIW of carbonaceous materials. Carbon-based materials, extensively used for various applications in 3D printing, possess impressive chemical stability, strength, and flexible nanostructure. Fine printable inks consist predominantly of uniform solutions of carbon materials, such as graphene, graphene oxide (GO), carbon fibers (CFs), carbon nanotubes (CNTs), and solvents. It also contains compatible polymers and suitable additives. This review article elaborately discusses the fundamental requirements of DIW in structuring carbon-doped polymeric inks viz. ink formulation, required ink rheology, extrusion parameters, print fidelity prediction, layer bonding examination, substrate selection, and curing method to achieve fine functional composites. A detailed description of its application in the fields of electronics, medical, and mechanical segments have also been focused in this study.
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Affiliation(s)
- Ratnesh Raj
- Department of Mechanical Engineering, Indian Institute of Technology (ISM), Dhanbad, India
| | - Amit Rai Dixit
- Department of Mechanical Engineering, Indian Institute of Technology (ISM), Dhanbad, India
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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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5
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Ma J, Krisnadi F, Vong MH, Kong M, Awartani OM, Dickey MD. Shaping a Soft Future: Patterning Liquid Metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205196. [PMID: 36044678 DOI: 10.1002/adma.202205196] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/23/2022] [Indexed: 05/12/2023]
Abstract
This review highlights the unique techniques for patterning liquid metals containing gallium (e.g., eutectic gallium indium, EGaIn). These techniques are enabled by two unique attributes of these liquids relative to solid metals: 1) The fluidity of the metal allows it to be injected, sprayed, and generally dispensed. 2) The solid native oxide shell allows the metal to adhere to surfaces and be shaped in ways that would normally be prohibited due to surface tension. The ability to shape liquid metals into non-spherical structures such as wires, antennas, and electrodes can enable fluidic metallic conductors for stretchable electronics, soft robotics, e-skins, and wearables. The key properties of these metals with a focus on methods to pattern liquid metals into soft or stretchable devices are summari.
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Affiliation(s)
- Jinwoo Ma
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Febby Krisnadi
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Man Hou Vong
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Minsik Kong
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Omar M Awartani
- Department of Mechanical Engineering, Maroun Semaan Faculty of Engineering and Architecture, American University of Beirut, Beirut, 1107-2020, Lebanon
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
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6
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Kim M, Lim H, Ko SH. Liquid Metal Patterning and Unique Properties for Next-Generation Soft Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205795. [PMID: 36642850 PMCID: PMC9951389 DOI: 10.1002/advs.202205795] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/27/2022] [Indexed: 05/28/2023]
Abstract
Room-temperature liquid metal (LM)-based electronics is expected to bring advancements in future soft electronics owing to its conductivity, conformability, stretchability, and biocompatibility. However, various difficulties arise when patterning LM because of its rheological features such as fluidity and surface tension. Numerous attempts are made to overcome these difficulties, resulting in various LM-patterning methods. An appropriate choice of patterning method based on comprehensive understanding is necessary to fully utilize the unique properties. Therefore, the authors aim to provide thorough knowledge about patterning methods and unique properties for LM-based future soft electronics. First, essential considerations for LM-patterning are investigated. Then, LM-patterning methods-serial-patterning, parallel-patterning, intermetallic bond-assisted patterning, and molding/microfluidic injection-are categorized and investigated. Finally, perspectives on LM-based soft electronics with unique properties are provided. They include outstanding features of LM such as conformability, biocompatibility, permeability, restorability, and recyclability. Also, they include perspectives on future LM-based soft electronics in various areas such as radio frequency electronics, soft robots, and heterogeneous catalyst. LM-based soft devices are expected to permeate the daily lives if patterning methods and the aforementioned features are analyzed and utilized.
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Affiliation(s)
- Minwoo Kim
- Applied Nano and Thermal Science LabDepartment of Mechanical EngineeringSeoul National University1 Gwanak‐ro, Gwanak‐guSeoul08826South Korea
| | - Hyungjun Lim
- Applied Nano and Thermal Science LabDepartment of Mechanical EngineeringSeoul National University1 Gwanak‐ro, Gwanak‐guSeoul08826South Korea
- Department of Mechanical EngineeringPohang University of Science and Technology77 Chungam‐ro, Nam‐guPohang37673South Korea
| | - Seung Hwan Ko
- Applied Nano and Thermal Science LabDepartment of Mechanical EngineeringSeoul National University1 Gwanak‐ro, Gwanak‐guSeoul08826South Korea
- Institute of Advanced Machinery and Design/Institute of Engineering ResearchSeoul National University1 Gwanak‐ro, Gwanak‐guSeoul08826South Korea
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7
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Recent Advances in Multi-Material 3D Printing of Functional Ceramic Devices. Polymers (Basel) 2022; 14:polym14214635. [PMID: 36365628 PMCID: PMC9654317 DOI: 10.3390/polym14214635] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
In recent years, functional ceramic devices have become smaller, thinner, more refined, and highly integrated, which makes it difficult to realize their rapid prototyping and low-cost manufacturing using traditional processing. As an emerging technology, multi-material 3D printing offers increased complexity and greater freedom in the design of functional ceramic devices because of its unique ability to directly construct arbitrary 3D parts that incorporate multiple material constituents without an intricate process or expensive tools. Here, the latest advances in multi-material 3D printing methods are reviewed, providing a comprehensive study on 3D-printable functional ceramic materials and processes for various functional ceramic devices, including capacitors, multilayer substrates, and microstrip antennas. Furthermore, the key challenges and prospects of multi-material 3D-printed functional ceramic devices are identified, and future directions are discussed.
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Kiss J, Balkay L, Kukuts K, Miko M, Forgacs A, Trencsenyi G, Krizsan AK. 3D printed anthropomorphic left ventricular myocardial phantom for nuclear medicine imaging applications. EJNMMI Phys 2022; 9:34. [PMID: 35503184 PMCID: PMC9065219 DOI: 10.1186/s40658-022-00461-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/20/2022] [Indexed: 11/26/2022] Open
Abstract
Background Anthropomorphic torso phantoms, including a cardiac insert, are frequently used to investigate the imaging performance of SPECT and PET systems. These phantom solutions are generally featuring a simple anatomical representation of the heart. 3D printing technology paves the way to create cardiac phantoms with more complex volume definition. This study aimed to describe how a fillable left ventricular myocardium (LVm) phantom can be manufactured using geometry extracted from a patient image. Methods The LVm of a healthy subject was segmented from 18F-FDG attenuation corrected PET image set. Two types of phantoms were created and 3D printed using polyethylene terephthalate glycol (PETG) material: one representing the original healthy LVm, and the other mimicking myocardium with a perfusion defect. The accuracy of the LVm phantom production was investigated by high-resolution CT scanning of 3 identical replicas. 99mTc SPECT acquisitions using local cardiac protocol were performed, without additional scattering media (“in air” measurements) for both phantom types. Furthermore, the healthy LVm phantom was inserted in the commercially available DataSpectrum Anthropomorphic Torso Phantom (“in torso” measurement) and measured with hot background and hot liver insert. Results Phantoms were easy to fill without any air-bubbles or leakage, were found to be reproducible and fully compatible with the torso phantom. Seventeen segments polar map analysis of the "in air” measurements revealed that a significant deficit in the distribution appeared where it was expected. 59% of polar map segments had less than 5% deviation for the "in torso” and "in air” measurement comparison. Excluding the deficit area, neither comparison had more than a 12.4% deviation. All the three polar maps showed similar apex and apical region values for all configurations. Conclusions Fillable anthropomorphic 3D printed phantom of LVm can be produced with high precision and reproducibility. The 3D printed LVm phantoms were found to be suitable for SPECT image quality tests during different imaging scenarios. The flexibility of the 3D printing process presented in this study provides scalable and anthropomorphic image quality phantoms in nuclear cardiology imaging.
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Affiliation(s)
- Janos Kiss
- Division of Radiology and Imaging Science, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98., Debrecen, 4032, Hungary.
| | - Laszlo Balkay
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98., Debrecen, 4032, Hungary
| | - Kornel Kukuts
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98., Debrecen, 4032, Hungary
| | - Marton Miko
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98., Debrecen, 4032, Hungary
| | - Attila Forgacs
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98., Debrecen, 4032, Hungary.,Mediso Ltd., Laborc Utca 3., Budapest, 1037, Hungary
| | - Gyorgy Trencsenyi
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98., Debrecen, 4032, Hungary
| | - Aron K Krizsan
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98., Debrecen, 4032, Hungary
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Jeon B, Jeong B, Park YL. Hybrid Mechanism of Electromagnetic and Piezoresistive Sensing Using a Soft Microfluidic Coil. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3152310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Roels E, Terryn S, Iida F, Bosman AW, Norvez S, Clemens F, Van Assche G, Vanderborght B, Brancart J. Processing of Self-Healing Polymers for Soft Robotics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104798. [PMID: 34610181 DOI: 10.1002/adma.202104798] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/27/2021] [Indexed: 06/13/2023]
Abstract
Soft robots are, due to their softness, inherently safe and adapt well to unstructured environments. However, they are prone to various damage types. Self-healing polymers address this vulnerability. Self-healing soft robots can recover completely from macroscopic damage, extending their lifetime. For developing healable soft robots, various formative and additive manufacturing methods have been exploited to shape self-healing polymers into complex structures. Additionally, several novel manufacturing techniques, noted as (re)assembly binding techniques that are specific to self-healing polymers, have been created. Herein, the wide variety of processing techniques of self-healing polymers for robotics available in the literature is reviewed, and limitations and opportunities discussed thoroughly. Based on defined requirements for soft robots, these techniques are critically compared and validated. A strong focus is drawn to the reversible covalent and (physico)chemical cross-links present in the self-healing polymers that do not only endow healability to the resulting soft robotic components, but are also beneficial in many manufacturing techniques. They solve current obstacles in soft robots, including the formation of robust multi-material parts, recyclability, and stress relaxation. This review bridges two promising research fields, and guides the reader toward selecting a suitable processing method based on a self-healing polymer and the intended soft robotics application.
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Affiliation(s)
- Ellen Roels
- Brubotics, Vrije Universiteit Brussel (VUB) and Imec, Pleinlaan 2, Brussels, 1050, Belgium
- Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Seppe Terryn
- Brubotics, Vrije Universiteit Brussel (VUB) and Imec, Pleinlaan 2, Brussels, 1050, Belgium
- Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Fumiya Iida
- Machine Intelligence Lab, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK
| | - Anton W Bosman
- SupraPolix B. V., Horsten 1.29, Eindhoven, 5612 AX, The Netherlands
| | - Sophie Norvez
- Chimie Moléculaire, Macromoléculaire, Matériaux, École Supérieure de Physique et de Chimie (ESPCI), 10 Rue Vauquelin, Paris, 75005, France
| | - Frank Clemens
- Laboratory for High Performance Ceramics, Swiss Federal Laboratories for Materials Science and Technology (EMPA), Überlandstrasse 129, Dübendorf, 8600, Switzerland
| | - Guy Van Assche
- Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Bram Vanderborght
- Brubotics, Vrije Universiteit Brussel (VUB) and Imec, Pleinlaan 2, Brussels, 1050, Belgium
| | - Joost Brancart
- Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
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11
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Han Y, Varadarajan A, Kim T, Zheng G, Kitani K, Kelliher A, Rikakis T, Park YL. Smart Skin: Vision-Based Soft Pressure Sensing System for In-Home Hand Rehabilitation. Soft Robot 2021; 9:473-485. [PMID: 34415805 PMCID: PMC9232239 DOI: 10.1089/soro.2020.0083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We introduce a novel in-home hand rehabilitation system for monitoring hand motions and assessing grip forces of stroke patients. The overall system is composed of a sensing device and a computer vision system. The sensing device is a lightweight cylindrical object for easy grip and manipulation, which is covered by a passive sensing layer called "Smart Skin." The Smart Skin is fabricated using soft silicone elastomer, which contains embedded microchannels partially filled with colored fluid. When the Smart Skin is compressed by grip forces, the colored fluid rises and fills in the top surface display area. Then, the computer vision system captures the image of the display area through a red-green-blue camera, detects the length change of the liquid through image processing, and eventually maps the liquid length to the calibrated force for estimating the gripping force. The passive sensing mechanism of the proposed Smart Skin device works in conjunction with a single camera setup, making the system simple and easy to use, while also requiring minimum maintenance effort. Our system, on one hand, aims to support home-based rehabilitation therapy with minimal or no supervision by recording the training process and the force data, which can be automatically conveyed to physical therapists. In contrast, the therapists can also remotely instruct the patients with their training prescriptions through online videos. This study first describes the design, fabrication, and calibration of the Smart Skin, and the algorithm for image processing, and then presents experimental results from the integrated system. The Smart Skin prototype shows a relatively linear relationship between the applied force and the length change of the liquid in the range of 0-35 N. The computer vision system shows the estimation error <4% and a relatively high stability in estimation under different hand motions.
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Affiliation(s)
- Yuanfeng Han
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aadith Varadarajan
- Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Taekyoung Kim
- Department of Mechanical Engineering, Institute of Advanced Machines and Design, Institute of Engineering Research, Seoul National University, Seoul, Korea
| | - Gang Zheng
- Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Kris Kitani
- Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Aisling Kelliher
- Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Thanassis Rikakis
- Department of Bioengineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Yong-Lae Park
- Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Mechanical Engineering, Institute of Advanced Machines and Design, Institute of Engineering Research, Seoul National University, Seoul, Korea
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Abstract
Soft wearable electronics are rapidly developing through exploration of new materials, fabrication approaches, and design concepts. Although there have been many efforts for decades, a resurgence of interest in liquid metals (LMs) for sensing and wiring functional properties of materials in soft wearable electronics has brought great advances in wearable electronics and materials. Various forms of LMs enable many routes to fabricate flexible and stretchable sensors, circuits, and functional wearables with many desirable properties. This review article presents a systematic overview of recent progresses in LM-enabled wearable electronics that have been achieved through material innovations and the discovery of new fabrication approaches and design architectures. We also present applications of wearable LM technologies for physiological sensing, activity tracking, and energy harvesting. Finally, we discuss a perspective on future opportunities and challenges for wearable LM electronics as this field continues to grow.
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Affiliation(s)
- Phillip Won
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea
| | - Seongmin Jeong
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea
| | - Carmel Majidi
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Seung Hwan Ko
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea
- Institute of Advanced Machines and Design / Institute of Engineering Research, Seoul National University, Seoul 08826, Korea
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Liu X, Wei Y, Qiu Y. Advanced Flexible Skin-Like Pressure and Strain Sensors for Human Health Monitoring. MICROMACHINES 2021; 12:695. [PMID: 34198673 PMCID: PMC8232132 DOI: 10.3390/mi12060695] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 12/24/2022]
Abstract
Recently, owing to their excellent flexibility and adaptability, skin-like pressure and strain sensors integrated with the human body have the potential for great prospects in healthcare. This review mainly focuses on the representative advances of the flexible pressure and strain sensors for health monitoring in recent years. The review consists of five sections. Firstly, we give a brief introduction of flexible skin-like sensors and their primary demands, and we comprehensively outline the two categories of design strategies for flexible sensors. Secondly, combining the typical sensor structures and their applications in human body monitoring, we summarize the recent development of flexible pressure sensors based on perceptual mechanism, the sensing component, elastic substrate, sensitivity and detection range. Thirdly, the main structure principles and performance characteristic parameters of noteworthy flexible strain sensors are summed up, namely the sensing mechanism, sensitive element, substrate, gauge factor, stretchability, and representative applications for human monitoring. Furthermore, the representations of flexible sensors with the favorable biocompatibility and self-driven properties are introduced. Finally, in conclusion, besides continuously researching how to enhance the flexibility and sensitivity of flexible sensors, their biocompatibility, versatility and durability should also be given sufficient attention, especially for implantable bioelectronics. In addition, the discussion emphasizes the challenges and opportunities of the above highlighted characteristics of novel flexible skin-like sensors.
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Affiliation(s)
- Xu Liu
- School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071, China
- School of Mechanical Engineering, Xi’an Aeronautical University, Xi’an 710077, China
| | - Yuan Wei
- Institute of Flexible Electronics, Northwestern Polytechnical University, Xi’an 710072, China;
| | - Yuanying Qiu
- School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071, China
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Kim D, Kim SH, Kim T, Kang BB, Lee M, Park W, Ku S, Kim D, Kwon J, Lee H, Bae J, Park YL, Cho KJ, Jo S. Review of machine learning methods in soft robotics. PLoS One 2021; 16:e0246102. [PMID: 33600496 PMCID: PMC7891779 DOI: 10.1371/journal.pone.0246102] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Soft robots have been extensively researched due to their flexible, deformable, and adaptive characteristics. However, compared to rigid robots, soft robots have issues in modeling, calibration, and control in that the innate characteristics of the soft materials can cause complex behaviors due to non-linearity and hysteresis. To overcome these limitations, recent studies have applied various approaches based on machine learning. This paper presents existing machine learning techniques in the soft robotic fields and categorizes the implementation of machine learning approaches in different soft robotic applications, which include soft sensors, soft actuators, and applications such as soft wearable robots. An analysis of the trends of different machine learning approaches with respect to different types of soft robot applications is presented; in addition to the current limitations in the research field, followed by a summary of the existing machine learning methods for soft robots.
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Affiliation(s)
- Daekyum Kim
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Neuro-Machine Augmented Intelligence Laboratory, School of Computing, KAIST, Daejeon, Korea
| | - Sang-Hun Kim
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Biorobotics Laboratory, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
| | - Taekyoung Kim
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Soft Robotics & Bionics Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Brian Byunghyun Kang
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Biorobotics Laboratory, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
| | - Minhyuk Lee
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Bio-Robotics and Control Laboratory, Department of Mechanical Engineering, UNIST, Ulsan, Korea
| | - Wookeun Park
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Bio-Robotics and Control Laboratory, Department of Mechanical Engineering, UNIST, Ulsan, Korea
| | - Subyeong Ku
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Soft Robotics & Bionics Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
| | - DongWook Kim
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Soft Robotics & Bionics Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Junghan Kwon
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Soft Robotics & Bionics Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Hochang Lee
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Neuro-Machine Augmented Intelligence Laboratory, School of Computing, KAIST, Daejeon, Korea
| | - Joonbum Bae
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Bio-Robotics and Control Laboratory, Department of Mechanical Engineering, UNIST, Ulsan, Korea
| | - Yong-Lae Park
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Soft Robotics & Bionics Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Kyu-Jin Cho
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Biorobotics Laboratory, Department of Mechanical Engineering, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
| | - Sungho Jo
- Soft Robotics Research Center, Seoul National University, Seoul, Korea
- Neuro-Machine Augmented Intelligence Laboratory, School of Computing, KAIST, Daejeon, Korea
- KAIST Institute for Artificial Intelligence, KAIST, Daejeon, Korea
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15
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Cheng M, Zhu G, Zhang F, Tang WL, Jianping S, Yang JQ, Zhu LY. A review of flexible force sensors for human health monitoring. J Adv Res 2020; 26:53-68. [PMID: 33133683 PMCID: PMC7584676 DOI: 10.1016/j.jare.2020.07.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/15/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In recent years, health monitoring systems (HMS) have aroused great interest due to their broad prospects in preventive medicine. As an important component of HMS, flexible force sensors (FFS) with high flexibility and stretch-ability can monitor vital health parameters and detect physical movements. AIM OF REVIEW In this review, the novel materials, the advanced additive manufacturing technologies, the selective sensing mechanisms and typical applications in both wearable and implantable HMS are discussed. KEY SCIENTIFIC CONCEPTS AND IMPORTANT FINDINGS OF REVIEW We recognized that the next generation of the FFS will have higher sensitivity, wider linear range as well as better durability, self-power supplied and multifunctional integrated. In conclusion, the FFS will provide powerful socioeconomic benefits and improve people's quality of life in the future.
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Affiliation(s)
- Ming Cheng
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
| | - Guotao Zhu
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
| | - Feng Zhang
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
- Nanjing Institute of Intelligent Advanced Equipment Industry Co., Ltd., Nanjing, China
| | - Wen-lai Tang
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
- Nanjing Institute of Intelligent Advanced Equipment Industry Co., Ltd., Nanjing, China
| | - Shi Jianping
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
- Nanjing Institute of Intelligent Advanced Equipment Industry Co., Ltd., Nanjing, China
| | - Ji-quan Yang
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
- Nanjing Institute of Intelligent Advanced Equipment Industry Co., Ltd., Nanjing, China
| | - Li-ya Zhu
- Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, China
- Nanjing Institute of Intelligent Advanced Equipment Industry Co., Ltd., Nanjing, China
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Park W, Seo S, Oh J, Bae J. A Sensorized Hybrid Gripper to Evaluate a Grasping Quality Based on a Largest Minimum Wrench. IEEE Robot Autom Lett 2020. [DOI: 10.1109/lra.2020.2976312] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Tapia J, Knoop E, Mutný M, Otaduy MA, Bächer M. MakeSense: Automated Sensor Design for Proprioceptive Soft Robots. Soft Robot 2019; 7:332-345. [PMID: 31891526 DOI: 10.1089/soro.2018.0162] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Soft robots have applications in safe human-robot interactions, manipulation of fragile objects, and locomotion in challenging and unstructured environments. In this article, we present a computational method for augmenting soft robots with proprioceptive sensing capabilities. Our method automatically computes a minimal stretch-receptive sensor network to user-provided soft robotic designs, which is optimized to perform well under a set of user-specified deformation-force pairs. The sensorized robots are able to reconstruct their full deformation state, under interaction forces. We cast our sensor design as a subselection problem, selecting a minimal set of sensors from a large set of fabricable ones, which minimizes the error when sensing specified deformation-force pairs. Unique to our approach is the use of an analytical gradient of our reconstruction performance measure with respect to selection variables. We demonstrate our technique on a bending bar and gripper example, illustrating more complex designs with a simulated tentacle.
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Affiliation(s)
- Javier Tapia
- Disney Research, Zurich, Switzerland.,Department of Computer Science, Universidad Rey Juan Carlos, Madrid, Spain
| | | | | | - Miguel A Otaduy
- Department of Computer Science, Universidad Rey Juan Carlos, Madrid, Spain
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Kim S, Oh J, Jeong D, Bae J. Direct Wiring of Eutectic Gallium-Indium to a Metal Electrode for Soft Sensor Systems. ACS APPLIED MATERIALS & INTERFACES 2019; 11:20557-20565. [PMID: 31066540 DOI: 10.1021/acsami.9b05363] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
For wider applications of liquid metal-based stretchable electronics, electrical interface has remained a crucial issue due to its fragile electromechanical stability and complex fabrication steps. In this study, a direct writing-based technique is introduced to form the writing paths of conductive liquid metal (eutectic gallium-indium, eGaIn) and electrical connections to off-the-shelf metal electrodes in a single process. Specifically, by extending eGaIn wires written on a silicone substrate, the eGaIn wires were physically connected to five different metal electrodes, of which stability as an electrical connection was investigated. Among the five different surface materials, the metal electrode finished by electroless nickel immersion gold (ENIG) was reproducible and had low contact resistance without time-dependent variation. In our experiments, it was verified that the electrode part made by an ENIG-finished flexible flat cable (FFC) was mechanically (strain, ≤100%; pressure, ≤600 kPa) and thermally (temperature, ≤180 °C) durable. By modifying the trajectories of eGaIn wires, soft sensor systems composed of 10 sensing units were fabricated and tested to measure finger joint angles and ground reaction forces, respectively. The proposed method enables eGaIn-based soft sensors or circuits to be connected to typical electronic components through FFCs or weldable surfaces, using only off-the-shelf materials without additional mechanical or chemical treatments.
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Affiliation(s)
- Suin Kim
- Department of Mechanical Engineering , UNIST , Ulsan 44919 , Korea
| | - Jihye Oh
- Department of Mechanical Engineering , UNIST , Ulsan 44919 , Korea
| | - Dahee Jeong
- Department of Mechanical Engineering , UNIST , Ulsan 44919 , Korea
| | - Joonbum Bae
- Department of Mechanical Engineering , UNIST , Ulsan 44919 , Korea
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Tang Z, Jia S, Shi X, Li B, Zhou C. Coaxial Printing of Silicone Elastomer Composite Fibers for Stretchable and Wearable Piezoresistive Sensors. Polymers (Basel) 2019; 11:polym11040666. [PMID: 30979015 PMCID: PMC6523915 DOI: 10.3390/polym11040666] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 11/23/2022] Open
Abstract
Despite the tremendous efforts dedicated to developing various wearable piezoresistive sensors with sufficient stretchability and high sensitivity, challenges remain pertaining to fabrication scalability, cost, and efficiency. In this study, a facile, scalable, and low-cost coaxial printing strategy is employed to fabricate stretchable and flexible fibers with a core–sheath structure for wearable strain sensors. The highly viscous silica-modified silicone elastomer solution is used to print the insulating sheath layer, and the silicone elastomer solutions containing multi-walled carbon nanotubes (CNTs) are used as the core inks to print the conductive inner layer. With the addition of silica powders as viscosifiers, silica-filled silicone ink (sheath ink) converts to printable ink. The dimensions of the printed coaxial fibers can be flexibly controlled via adjusting the extrusion pressure of the inks. In addition, the electro-mechanical responses of the fiber-shaped strain sensors are investigated. The printed stretchable and wearable fiber-like CNT-based strain sensor exhibits outstanding sensitivities with gauge factors (GFs) of 1.4 to 2.5 × 106, a large stretchability of 150%, and excellent waterproof performance. Furthermore, the sensor can detect a strain of 0.1% and showed stable responses for over 15,000 cycles (high durability). The printed fiber-shaped sensor demonstrated capabilities of detecting and differentiating human joint movements and monitoring balloon inflation. These results obtained demonstrate that the one-step printed fiber-like strain sensors have potential applications in wearable devices, soft robotics, and electronic skins.
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Affiliation(s)
- Zhenhua Tang
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Shuhai Jia
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Xuesong Shi
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Bo Li
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Chenghao Zhou
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
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