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Park B, Jeong C, Ok J, Kim TI. Materials and Structural Designs toward Motion Artifact-Free Bioelectronics. Chem Rev 2024; 124:6148-6197. [PMID: 38690686 DOI: 10.1021/acs.chemrev.3c00374] [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: 05/02/2024]
Abstract
Bioelectronics encompassing electronic components and circuits for accessing human information play a vital role in real-time and continuous monitoring of biophysiological signals of electrophysiology, mechanical physiology, and electrochemical physiology. However, mechanical noise, particularly motion artifacts, poses a significant challenge in accurately detecting and analyzing target signals. While software-based "postprocessing" methods and signal filtering techniques have been widely employed, challenges such as signal distortion, major requirement of accurate models for classification, power consumption, and data delay inevitably persist. This review presents an overview of noise reduction strategies in bioelectronics, focusing on reducing motion artifacts and improving the signal-to-noise ratio through hardware-based approaches such as "preprocessing". One of the main stress-avoiding strategies is reducing elastic mechanical energies applied to bioelectronics to prevent stress-induced motion artifacts. Various approaches including strain-compliance, strain-resistance, and stress-damping techniques using unique materials and structures have been explored. Future research should optimize materials and structure designs, establish stable processes and measurement methods, and develop techniques for selectively separating and processing overlapping noises. Ultimately, these advancements will contribute to the development of more reliable and effective bioelectronics for healthcare monitoring and diagnostics.
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Affiliation(s)
- Byeonghak Park
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Chanho Jeong
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Jehyung Ok
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Tae-Il Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
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Rehman WU, Manj RZA, Ma Y, Yang J. The Promising Potential of Gallium Based Liquid Metals for Energy Storage. Chempluschem 2024:e202300767. [PMID: 38696273 DOI: 10.1002/cplu.202300767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/28/2024] [Accepted: 04/30/2024] [Indexed: 05/04/2024]
Abstract
Energy storage devices play a crucial role in various applications, such as powering electronics, power backup for homes and businesses, and support for the integration of renewable energy sources into electrical grid applications. Electrode materials for energy storage devices are preferred to have a flexible nature, conductive, better capacity, and low-toxicity. Using Gallium based liquid metal alloys, such as Eutectic Gallium-Indium (EGaIn), Eutectic Gallium-Tin (EGaSn), and Eutectic Gallium-Indium-Tin (EGaInSn), as electrode materials play very important role in energy storage devices. These liquid metals have some interesting properties with a self-healing nature, high mechanical stability, compatibility with various materials, fluidity, low young's modulus, high electrical and thermal conductivity. Those properties have made it suitable to be used in various energy storage devices. In this mini review, we have concisely described the advantages and challenges of using liquid metal as electrode materials for various energy storage devices.
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Affiliation(s)
- Waheed Ur Rehman
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - Rana Zafar Abbas Manj
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - Yuanyuan Ma
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - Jianping Yang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
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Zhang M, Shi Y, Ge H, Sun G, Lian Z, Lu Y. High-Performance Four-Channel Tactile Sensor for Measuring the Magnitude and Orientation of Forces. SENSORS (BASEL, SWITZERLAND) 2024; 24:2808. [PMID: 38732914 PMCID: PMC11086079 DOI: 10.3390/s24092808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 04/23/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024]
Abstract
Flexible sensors have gained popularity in recent years. This study proposes a novel structure of a resistive four-channel tactile sensor capable of distinguishing the magnitude and direction of normal forces acting on its sensing surface. The sensor uses EcoflexTM00-30 as the substrate and EGaIn alloy as the conductive filler, featuring four mutually perpendicular and curved channels to enhance the sensor's dynamic responsiveness. Experiments and simulations show that the sensor has a large dynamic range (31.25-100 mΩ), high precision (deviation of repeated pressing below 0.1%), linearity (R2 above 0.97), fast response/recovery time (0.2 s/0.15 s), and robust stability (with fluctuations below 0.9%). This work uses an underactuated robotic hand equipped with a four-channel tactile sensor to grasp various objects. The sensor data collected effectively predicts the shapes of the objects grasped. Furthermore, the four-channel tactile sensor proposed in this work may be employed in smart wearables, medical diagnostics, and other industries.
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Affiliation(s)
| | - Yong Shi
- School of Mechanical Engineering, Heilongjiang University, Harbin 150001, China; (M.Z.); (H.G.); (G.S.); (Z.L.); (Y.L.)
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Rahmani P, Shojaei A, Sakorikar T, Wang M, Mendoza-Apodaca Y, Dickey MD. Liquid Metal Nanoparticles Physically Hybridized with Cellulose Nanocrystals Initiate and Toughen Hydrogels with Piezoionic Properties. ACS NANO 2024; 18:8038-8050. [PMID: 38437220 DOI: 10.1021/acsnano.3c11063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
Liquid metal (LM) particles can serve as initiators, functional fillers, and cross-linkers for hydrogels. Herein, we show that cellulose nanocrystals (CNCs) stabilize LM particles in aqueous solutions, such as those used to produce hydrogels. The CNC-coated LM particles initiate free-radical polymerization to form poly(acrylic acid) (PAA) hydrogel with exceptional properties─stretchability ∼2000%, excellent toughness ∼1.8 MJ/m3, mechanical resilience, and efficient self-healing─relative to cross-linked PAA networks polymerized using conventional molecular initiators. FTIR spectroscopy, rheology, and mechanical measurements suggest that physical bonds between PAA and both Ga3+ and LM-CNC particles contribute to the excellent mechanical properties. The gels are used to sense a wide range of strains, such as those associated with human motion, via changes in resistance through the gel. The sensitivity at low strains enables monitoring subtle physiological signals, such as pulse. Without significantly compromising the toughness, soaking the gels in salt solution brings about high ionic conductivity (3.8 S/m), enabling them to detect touch via piezoionic principles; the anions in the gel have higher mobility than cations, resulting in significant charge separation (current ∼30 μA, ∼10 μA/cm2) through the gel in response to touch. These attractive properties are promising for wearable sensors, energy harvesters, and self-powered ionic touch panels.
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Affiliation(s)
- Pooria Rahmani
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran 14588-89694, Iran
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Akbar Shojaei
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran 14588-89694, Iran
| | - Tushar Sakorikar
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Meixiang Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yuniva Mendoza-Apodaca
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
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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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Ma B, Zhang J, Chen G, Chen Y, Xu C, Lei L, Liu H. Shape-Programmable Liquid Metal Fibers. BIOSENSORS 2022; 13:bios13010028. [PMID: 36671863 PMCID: PMC9856024 DOI: 10.3390/bios13010028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 05/28/2023]
Abstract
Conductive and stretchable fibers are the cornerstone of intelligent textiles and imperceptible electronics. Among existing fiber conductors, gallium-based liquid metals (LMs) featuring high conductivity, fluidity, and self-healing are excellent candidates for highly stretchable fibers with sensing, actuation, power generation, and interconnection functionalities. However, current LM fibers fabricated by direct injection or surface coating have a limitation in shape programmability. This hinders their applications in functional fibers with tunable electromechanical response and miniaturization. Here, we reported a simple and efficient method to create shape-programmable LM fibers using the phase transition of gallium. Gallium metal wires in the solid state can be easily shaped into a 3D helical structure, and the structure can be preserved after coating the wire with polyurethane and liquifying the metal. The 3D helical LM fiber offered enhanced stretchability with a high breaking strain of 1273% and showed invariable conductance over 283% strain. Moreover, we can reduce the fiber diameter by stretching the fiber during the solidification of polyurethane. We also demonstrated applications of the programmed fibers in self-powered strain sensing, heart rate monitoring, airflow, and humidity sensing. This work provided simple and facile ways toward functional LM fibers, which may facilitate the broad applications of LM fibers in e-skins, wearable computation, soft robots, and smart fabrics.
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Influence of microstructural alterations of liquid metal and its interfacial interactions with rubber on multifunctional properties of soft composite materials. Adv Colloid Interface Sci 2022; 308:102752. [PMID: 36007286 DOI: 10.1016/j.cis.2022.102752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/23/2022]
Abstract
Liquid metal (LM)-based polymer composites are currently new breakthrough and emerging classes of soft multifunctional materials (SMMs) having immense transformative potential for soft technological applications. Currently, room-temperature LMs, mostly eutectic gallium‑indium and Galinstan alloys are used to integrate with soft polymer due to their outstanding properties such as high conductivity, fluidity, low adhesion, high surface tension, low cytotoxicity, etc. The microstructural alterations and interfacial interactions controlling the efficient integration of LMs with rubber are the most critical aspects for successful implementation of multifunctionality in the resulting material. In this review article, a fundamental understanding of microstructural alterations of LMs to the formation of well-defined percolating networks inside an insulating rubber matrix has been established by exploiting several existing theoretical and experimental studies. Furthermore, effects of the chemical modifications of an LM surface and its interfacial interactions on the compatibility between solid rubber and fluid filler phase have been discussed. The presence of thin oxide layer on the LM surface and the effects and challenges it poses to the adequate functionalization of these materials have been discussed. Plausible applications of SMMs in different soft matter technologies, like soft robotics, flexible electronics, soft actuators, sensors, etc. have been provided. Finally, the current technical challenges and further prospective to the development of SMMs using non‑silicone rubbers have been critically discussed. This review is anticipated to infuse a new impetus to the associated research communities for the development of next generation SMMs.
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Uzabakiriho PC, Wang M, Ma C, Zhao G. Stretchable, breathable, and highly sensitive capacitive and self-powered electronic skin based on core-shell nanofibers. NANOSCALE 2022; 14:6600-6611. [PMID: 35421886 DOI: 10.1039/d2nr00444e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fiber-based nanostructures are greatly desired for the improvement of wearable/flexible electronics, which are expected to be stretchable, conformable, flexible, and long-term. Herein, an ultra-stretchable, breathable, and highly sensitive flexible capacitive tactile sensor and triboelectric effect core-shell nanofibers are proposed. In particular, core-shell ionic TPU/PVDF-HFP nanofibers are effectively prepared by an electrospinning approach. The core-shell ionic TPU/PVDF-HFP nanofibers exhibit high performance as a capacitive flexible sensor with high sensitivity (0.718 kPa-1) in a low linear pressure range (0-1.2 kPa), an ultralow detection limit (7 Pa), a rapid response and recovery time, and excellent stability. Moreover, we assembled a self-powered pressure sensor, which has a sensitivity of 0.071 V kPa-1 in the high linear pressure range of 90 kPa to 400 kPa. The increase in the inductive charges of the nanofiber layer allows it to work as an energy harvester with a high power density (1.6 W m-2) that can light up 100 LEDs instantly. These remarkable results allow the capacitive flexible devices to be applied in various applications, such as spatial pressure mapping, bending angle detection, soft grabbing, and physiological signal monitoring.
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Affiliation(s)
- Pierre Claver Uzabakiriho
- Department of Electronic Science and Technology, University of Science and Technology of China, Road JinZhai 96, Hefei 230027, P. R. China.
| | - Meng Wang
- Department of Electronic Science and Technology, University of Science and Technology of China, Road JinZhai 96, Hefei 230027, P. R. China.
| | - Chao Ma
- Department of Electronic Science and Technology, University of Science and Technology of China, Road JinZhai 96, Hefei 230027, P. R. China.
| | - Gang Zhao
- Department of Electronic Science and Technology, University of Science and Technology of China, Road JinZhai 96, Hefei 230027, P. R. China.
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