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Liu S, Shi J, Liu D, Wang H, Xiong J, Du Z. A Flexible and Adhesive Strain Sensor Based on Deep Eutectic Solvents for Deep Learning-Assisted Signal Recognition. ACS APPLIED MATERIALS & INTERFACES 2025; 17:27076-27091. [PMID: 40274546 DOI: 10.1021/acsami.4c20392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2025]
Abstract
Flexible wearable electronic devices have garnered significant interest due to their inherent properties, serving as replacements for traditional rigid metal conductors in personal healthcare monitoring, human motion detection, and sensory skin applications. Here, we report a preparation strategy for a self-adhesive, ultrahigh stretchable DGel based on poly(acrylic acid) (PAA). The resulting DGel exhibits a high tensile strength (approximately 2.16 MPa) and an ultrahigh stretchability (approximately 5622.14%). More importantly, these meticulously designed DES gels demonstrate high signal recognition capabilities under strains ranging from 1 to 500%. DGel also shows excellent cyclic stability and durability (5000 cycles at 100% strain), exhibiting a superior electromechanical performance as a strain sensor. The ultrahigh strength of DGel is attributed to the synergistic effects of chemical and physical cross-linking within the gel. Additionally, DGel can be effortlessly assembled into wearable sensors. By integration of flexible sensing with deep learning, the fabricated touch recognition system achieves an identification accuracy of up to 99.33%. This advancement offers new insights into designing novel gels for a variety of applications, including tissue engineering, sensing, and wearable electronic devices.
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Affiliation(s)
- Shuai Liu
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China
| | - Jianyang Shi
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China
| | - Dandan Liu
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China
| | - Haibo Wang
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China
- Qingdao Institute, Sichuan University, Qingdao 266000, P. R. China
- Research Institutes of Leather and Footwear Industry of Wenzhou, Wenzhou 325000, China
| | - Junjie Xiong
- Division of Pancreatic Surgery, Department of General Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Zongliang Du
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China
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2
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Kalulu M, Chilikwazi B, Hu J, Fu G. Soft Actuators and Actuation: Design, Synthesis, and Applications. Macromol Rapid Commun 2025; 46:e2400282. [PMID: 38850266 DOI: 10.1002/marc.202400282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/31/2024] [Indexed: 06/10/2024]
Abstract
Soft actuators are one of the most promising technological advancements with potential solutions to diverse fields' day-to-day challenges. Soft actuators derived from hydrogel materials possess unique features such as flexibility, responsiveness to stimuli, and intricate deformations, making them ideal for soft robotics, artificial muscles, and biomedical applications. This review provides an overview of material composition and design techniques for hydrogel actuators, exploring 3D printing, photopolymerization, cross-linking, and microfabrication methods for improved actuation. It examines applications of hydrogel actuators in biomedical, soft robotics, bioinspired systems, microfluidics, lab-on-a-chip devices, and environmental, and energy systems. Finally, it discusses challenges, opportunities, advancements, and regulatory aspects related to hydrogel actuators.
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Affiliation(s)
- Mulenga Kalulu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning, Nanjing, Jiangsu Province, 211189, P. R. China
- Department of Chemistry, School of Natural Sciences, The University of Zambia, Lusaka, 10101, Zambia
| | - Bright Chilikwazi
- Department of Chemistry, School of Natural Sciences, The University of Zambia, Lusaka, 10101, Zambia
| | - Jun Hu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning, Nanjing, Jiangsu Province, 211189, P. R. China
| | - Guodong Fu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning, Nanjing, Jiangsu Province, 211189, P. R. China
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3
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Zhang M, Ren J, Li R, Zhang W, Li Y, Yang W. Ultrastretchable and highly sensitive ionic conductive hydrogel for environmentally resistant all-in-one human-motion sensors. Int J Biol Macromol 2025; 287:138567. [PMID: 39653198 DOI: 10.1016/j.ijbiomac.2024.138567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2024] [Revised: 12/02/2024] [Accepted: 12/06/2024] [Indexed: 12/21/2024]
Abstract
Conductive hydrogels have been considered ideal candidate materials for fabricating human-motion sensors due to their combination properties of electronic and tissue-like soft nature and the similar functions of human skin with mechanical and sensory properties. However, the perfect integration of multiple functionalities such as environmentally tolerant, stretchable, self-adhesive, self-healing, transparent, high sensitivity, and rapid response in one system (all-in-one) is still a significant challenge. Herein, a novel ionic conductive hydrogel platform with excellent comprehensive performance through multiple dynamic interactions was prepared by employing [BMIm]BF4/glycerol/water ternary solvent system. The dynamic hydrogen bonds, coordination bonds, and electrostatic interaction within the network endows the hydrogel excellent mechanical performance. The synchronous effect of ionic liquids and glycerol realized the high ionic conductivity, transparency, environmentally tolerance, and long-term stability. Sensors based on this hydrogel have a relatively high sensitivity, a fast response time, and a wide linear sensing range in monitoring human movements. It can also serve as electronic skin, like human skin, for touchscreen pen and writing. Thus, the all-in-one hydrogel was concluded to hold considerable promise for constructing the next generation of hydrogel platforms for human-motion sensors.
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Affiliation(s)
- Minmin Zhang
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China
| | - Jie Ren
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China.
| | - Ruirui Li
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China
| | - Wenjing Zhang
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China
| | - Yan Li
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China
| | - Wu Yang
- Chemistry & Chemical Engineering College, Northwest Normal University, Key Lab of Polymer Materials of Ministry of Education of Ecological Environment, Key Lab of Bioelectrochemistry & Environmental Analysis of Gansu, Lanzhou 730070, PR China
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Zhou S, Zhang Z, Zhong W, Meng A, Su Y. Polyvinyl alcohol/PEDOT:PSS with Fe 3+/amylopectin enabled highly tough, anti-freezing and healable hydrogels for multifunctional wearable sensors. Talanta 2024; 279:126592. [PMID: 39053360 DOI: 10.1016/j.talanta.2024.126592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 07/01/2024] [Accepted: 07/18/2024] [Indexed: 07/27/2024]
Abstract
In recent years, hydrogel-based flexible sensors have garnered increasing attention in research. Ionic hydrogels, enriched with large amounts of ionic liquids, exhibit electrical conductivity, excellent electrochemical stability, anti-freezing, and antimicrobial properties. However, most ionic hydrogels suffer from poor mechanical properties, limiting their adaptability to more complex application scenarios. Integrating conductive polymers into hydrogels leads to desirable features such as increased specific surface area, soft and biocompatible interfaces, and high electrolyte permeability. In this study, we successfully prepared Fe3+/Ap@PVA/PEDOT double-network hydrogel. Utilizing polyvinyl alcohol (PVA) as the primary matrix, we introduced PEDOT:PSS and FeCl3 to confer conductivity to the hydrogel. The incorporation of amylopectin (Ap) further enhanced mechanical performance. The resulted hydrogel sensor exhibits outstanding mechanical properties, allowing for stretching up to 347 % and withstanding a tensile force of 505 kPa. In addition, it exhibits excellent antifreeze properties (can work at -30 °C), healability, water retention, and high sensitivity to stretching (GF = 4.72 at a 200 % strain ratio), compression (GF = 2.97 at a 12 % compressive ratio), and temperature (TCR = 2.46). These remarkable properties of the hydrogel make it possible in applications such as human motion monitoring, handwriting recognition, and temperature sensing.
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Affiliation(s)
- Shuang Zhou
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, PR China
| | - Zheng Zhang
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, PR China
| | - Wei Zhong
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, PR China
| | - Aiyun Meng
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, PR China.
| | - Yaorong Su
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, PR China.
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Zhou B, Yuan W. Tunable thermoresponsive and stretchable hydrogel sensor based on hydroxypropyl cellulose for human motion/health detection, visual signal transmission and information encryption. Carbohydr Polym 2024; 343:122497. [PMID: 39174144 DOI: 10.1016/j.carbpol.2024.122497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 07/12/2024] [Accepted: 07/13/2024] [Indexed: 08/24/2024]
Abstract
Thermoresponsive hydrogels can be used as smart flexible sensors. However, the design and facile preparation of multifunctional thermoresponsive hydrogel sensors still face great challenges. Herein, a tunable thermoresponsive, thermochromic and stretchable poly(2-hydroxypropyl acrylate-co-acrylamide) (P(HPA-co-AM))/hydroxypropyl cellulose (HPC)/lithium chloride (LiCl) hydrogel with the networks constructed from non-covalent interaction was fabricated by photopolymerization. PHPA exhibits excellent thermoresponsiveness. HPC endows the hydrogel with outstanding mechanical performance and enhanced temperature-sensitivity. LiCl not only provides good conductivity, but also regulates the lower critical solution temperature (LCST) of the hydrogel. The hydrogel shows tensile strength up to 300 kPa and maximum strain up to 790 %. The LCST value of the hydrogel can be adjusted from 38 to 75 °C. Therefore, the thermoresponsive conductive hydrogel can realize the information encryption, and be used as sensor through strain and temperature changes in the external environment to realize the motion and health detection, and visual signal transmission. This work is expected to provide ideas for the next generation of smart multifunctional electronic skin and information encryption device.
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Affiliation(s)
- Bo Zhou
- School of Materials Science and Engineering, Key Laboratory of Advanced Civil Materials of Ministry of Education, Tongji University, Shanghai 201804, People's Republic of China
| | - Weizhong Yuan
- School of Materials Science and Engineering, Key Laboratory of Advanced Civil Materials of Ministry of Education, Tongji University, Shanghai 201804, People's Republic of China.
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Lu Z, Liu L, Miao R, Zhang N, Gao M, Fan X, Li Y. Lignin sulfonate induced ultrafast fabrication of polypyrrole-based conductive organohydrogel for high performance flexible strain and temperature sensor. Int J Biol Macromol 2024; 282:136969. [PMID: 39490480 DOI: 10.1016/j.ijbiomac.2024.136969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2024] [Revised: 10/12/2024] [Accepted: 10/25/2024] [Indexed: 11/05/2024]
Abstract
The ultrafast preparation of electrically conductive hydrogels to endow high sensing performance and temperature tolerance remains a critical challenge. Herein, lignosulfonate sodium-templated polypyrrole (LS-PPy) nanofillers were rapidly introduced into polyacrylic acid (PAA) hydrogel through ultrafast free radical polymerization in a glycerol/water binary solvent system. The resultant LS-PPy/PAA electrically conductive organohydrogel possesses satisfactory mechanical performance (strength of 56 kPa at a tensile strain of 800 %), strong adhesion, and a desirable low freezing point (-35 °C). Furthermore, this organohydrogel exhibits high strain sensitivity (gauge factor = 2.65), fast response time (~160 ms), low signal hysteresis, and excellent cyclic stability (over 1200 cycles). And the wearable LS-PPy/PAA organohydrogel sensor could accurately and real-time monitor various intense or subtle human movements, such as joint bending, facial expression and hand writing. Besides, the developed LS-PPy/PAA temperature sensor can respond to environmental temperature variations over a wide range of -20-100 °C. High resolution of 0.5 °C with remarkable sensitivity (-0.80 %/°C and linearity of R2 = 0.99) and repeatability were achieved within 36.5-40 °C, which makes it suitable for human body temperature monitoring. All these results demonstrate the substantial prospective value of the LS-PPy/PAA hydrogel in wearable sensors and other associated fields.
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Affiliation(s)
- Zichun Lu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Lingke Liu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - RunTian Miao
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Ning Zhang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Minjuan Gao
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Xingyu Fan
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Yueqin Li
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037, China.
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7
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Wang R, Liu C, Li Z, Li Y, Yu X. Ultra-Stretchable, Adhesive, Conductive, and Antifreezing Multinetwork Borate Ester-Based Hydrogel for Wearable Strain Sensor and VOC Absorption. ACS Sens 2024; 9:5322-5332. [PMID: 39404651 DOI: 10.1021/acssensors.4c01567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2024]
Abstract
Hydrogels based on borate ester bonds exhibit remarkable tensile strength and self-healing ability, which make them a promising material for various biological research and strain sensor applications. However, in order to meet the practical application of hydrogel strain sensors, they must also show high conductivity, frost resistance, and proper adhesion, which is still a continuous challenge. Herein, a triple network hydrogel was prepared using poly(vinyl alcohol) (PVA) as the first network, ethylene imine polymer (PEI) as the second network, and poly(acrylamide-co-acrylic acid) copolymer (denoted as P(AM-Co-AA)) as the third network. 3-Carboxy-4-fluorophenylboronic acid (CFBS) was used as the cross-linking agent, glycerol (GL) was added to improve low-temperature resistance, and sodium chloride (NaCl) was incorporated to enhance electrical conductivity. The resulting PVA-CFBS@PEI@P(AM-Co-AA) triple network hydrogel exhibited impressive mechanical properties, including ultra tensile strength (4100%, 266.8 kPa), high toughness (6.5 MJ/m3), and low-temperature resistance (-60 °C). Additionally, it demonstrated high conductivity (σ = 1.83 mS/cm). The incorporation of CFBS endowed the hydrogel with excellent self-healing ability, while GL improved low-temperature resistance and strain sensing sensitivity (gauge factor (GF) = 2.8 (0-300%), GF = 5.6 (300-600%), GF = 8.7 (600-1000%)). The prepared hydrogel sensor can repetitively detect and differentiate between a wide range of human activities such as joint movements, frowning, and smiling. Additionally, the hydrogel demonstrated favorable mechanical properties at -20 °C (good adhesion, tensile strength: 1169.8%, 1.2 MPa; conductivity: 0.71 mS/cm, and strain sensing coefficient: GF = 1.3), making it suitable for applications in low-temperature environments. Furthermore, it also functions as an exceptional adsorbent, capable of selectively absorbing volatile organic compounds at high capacity (e.g., methanol: 1.80 g/g; acetone: 1.50 g/g).
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Affiliation(s)
- Ruixue Wang
- Hebei Provincial Key Laboratory of Photoelectric Control on Surface and Interface, and College of Science, Hebei University of Science and Technology, Yuxiang Street 26, Shijiazhuang 050080, PR China
| | - Chunjiao Liu
- Hebei Provincial Key Laboratory of Photoelectric Control on Surface and Interface, and College of Science, Hebei University of Science and Technology, Yuxiang Street 26, Shijiazhuang 050080, PR China
| | - Zhongwan Li
- Hebei Provincial Key Laboratory of Photoelectric Control on Surface and Interface, and College of Science, Hebei University of Science and Technology, Yuxiang Street 26, Shijiazhuang 050080, PR China
| | - Yajuan Li
- Hebei Provincial Key Laboratory of Photoelectric Control on Surface and Interface, and College of Science, Hebei University of Science and Technology, Yuxiang Street 26, Shijiazhuang 050080, PR China
| | - Xudong Yu
- Hebei Provincial Key Laboratory of Photoelectric Control on Surface and Interface, and College of Science, Hebei University of Science and Technology, Yuxiang Street 26, Shijiazhuang 050080, PR China
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Liang Y, Lin L, Liang H, Zhong Z. Longevous ionogels with high strength, conductivity, adhesion and thermoplasticity. CHEMICAL ENGINEERING JOURNAL 2024; 497:155047. [DOI: 10.1016/j.cej.2024.155047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2024]
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9
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Mo F, Zhou P, Lin S, Zhong J, Wang Y. A Review of Conductive Hydrogel-Based Wearable Temperature Sensors. Adv Healthc Mater 2024; 13:e2401503. [PMID: 38857480 DOI: 10.1002/adhm.202401503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/04/2024] [Indexed: 06/12/2024]
Abstract
Conductive hydrogel has garnered significant attention as an emergent candidate for diverse wearable sensors, owing to its remarkable and tailorable properties such as flexibility, biocompatibility, and strong electrical conductivity. These attributes make it highly suitable for various wearable sensor applications (e.g., biophysical, bioelectrical, and biochemical sensors) that can monitor human health conditions and provide timely interventions. Among these applications, conductive hydrogel-based wearable temperature sensors are especially important for healthcare and disease surveillance. This review aims to provide a comprehensive overview of conductive hydrogel-based wearable temperature sensors. First, this work summarizes different types of conductive fillers-based hydrogel, highlighting their recent developments and advantages as wearable temperature sensors. Next, this work discusses the sensing characteristics of conductive hydrogel-based wearable temperature sensors, focusing on sensitivity, dynamic stability, stretchability, and signal output. Then, state-of-the-art applications are introduced, ranging from body temperature detection and wound temperature detection to disease monitoring. Finally, this work identifies the remaining challenges and prospects facing this field. By addressing these challenges with potential solutions, this review hopes to shed some light on future research and innovations in this promising field.
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Affiliation(s)
- Fan Mo
- Department of Biotechnology and Food Engineering, Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong, 515063, China
| | - Pengcheng Zhou
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong, 515063, China
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Shihong Lin
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong, 515063, China
| | - Junwen Zhong
- Department of Electromechanical Engineering, University of Macau, Macau, 999078, China
| | - Yan Wang
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong, 515063, China
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
- Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion, Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong, 515063, China
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10
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Condò I, Giannitelli SM, Lo Presti D, Cortese B, Ursini O. Overview of Dynamic Bond Based Hydrogels for Reversible Adhesion Processes. Gels 2024; 10:442. [PMID: 39057465 PMCID: PMC11275299 DOI: 10.3390/gels10070442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
Polymeric hydrogels are soft materials with a three-dimensional (3D) hydrophilic network capable of retaining and absorbing large amounts of water or biological fluids. Due to their customizable properties, these materials are extensively studied for developing matrices for 3D cell culture scaffolds, drug delivery systems, and tissue engineering. However, conventional hydrogels still exhibit many drawbacks; thus, significant efforts have been directed towards developing dynamic hydrogels that draw inspiration from organisms' natural self-repair abilities after injury. The self-healing properties of these hydrogels are closely associated with their ability to form, break, and heal dynamic bonds in response to various stimuli. The primary objective of this review is to provide a comprehensive overview of dynamic hydrogels by examining the types of chemical bonds associated with them and the biopolymers utilized, and to elucidate the chemical nature of dynamic bonds that enable the modulation of hydrogels' properties. While dynamic bonds ensure the self-healing behavior of hydrogels, they do not inherently confer adhesive properties. Therefore, we also highlight emerging approaches that enable dynamic hydrogels to acquire adhesive properties.
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Affiliation(s)
- Ilaria Condò
- Department of Engineering, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo 21, 00128 Rome, Italy; (I.C.); (D.L.P.)
| | - Sara Maria Giannitelli
- Department of Science and Technology for Sustainable Development and One Health, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo 21, 00128 Rome, Italy;
| | - Daniela Lo Presti
- Department of Engineering, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo 21, 00128 Rome, Italy; (I.C.); (D.L.P.)
- Fondazione Policlinico Universitario Campus Bio-Medico, Via Álvaro del Portillo 200, 00128 Rome, Italy
| | - Barbara Cortese
- National Research Council—Institute of Nanotechnology (CNR-Nanotec), Università La Sapienza, c/o Edificio Fermi, Pz.le Aldo Moro 5, 00185 Rome, Italy;
| | - Ornella Ursini
- National Research Council—Institute of Nanotechnology (CNR-Nanotec), Università La Sapienza, c/o Edificio Fermi, Pz.le Aldo Moro 5, 00185 Rome, Italy;
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Ren Y, Zou B, Wu Y, Ye L, Liang Y, Li Y. Acryloyl chitosan as a macro-crosslinker for freezing-resistant, self-healing and self-adhesive ionogels-based multicompetent flexible sensors. Int J Biol Macromol 2024; 273:133002. [PMID: 38851613 DOI: 10.1016/j.ijbiomac.2024.133002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/23/2024] [Accepted: 06/05/2024] [Indexed: 06/10/2024]
Abstract
Here, a polysaccharide derivative acryloyl chitosan (AcCS) is exploited as macro-crosslinker to synthesize a novel ionogel poly (acrylic acid-co-1-Vinyl-3-butyl imidazolium chloride) (AA-IL/AcCS) via a one-pot method. AcCS provides abundant physical and chemical crosslinking sites contributing to the high mechanical stretchability (elongation at break 600 %) and strength (tensile strength 137 kPa) of AA-IL/AcCS. The high-density of dynamic bonds (hydrogen bonds and electrostatic interactions) in the network of ionogels enables self-healing and self-adhesive features of AA-IL/AcCS. Meanwhile, AA-IL/AcCS exhibits high ionic conductivity (0.1 mS/cm) at room temperature and excellent antifreeze ability (-58 °C). The AA-IL/AcCS-based sensor shows diverse sensory capabilities towards temperature and humidity, moreover, it could precisely detect human motions and handwritings signals. Furthermore, AA-IL/AcCS exhibits excellent bactericidal properties against both gram-positive and gram-negative bacteria. This work opens the possibility of polysaccharides as a macro-crosslinkers for preparing ionogel-based sensors for wearable electronics.
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Affiliation(s)
- Yuanyuan Ren
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China
| | - Binhu Zou
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China
| | - Yantong Wu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China
| | - Lijun Ye
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China
| | - Yuanyuan Liang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China.
| | - Yongjin Li
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Rd., 311121 Hangzhou, PR China.
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12
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Lan M, Zhang J, Zhou J, Gu H. CQDs-Cross-Linked Conductive Collagen/PAA-Based Nanocomposite Organohydrogel Coupling Flexibility with Multifunctionality for Dual-Modal Sensing of Human Motions. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38676634 DOI: 10.1021/acsami.4c00848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2024]
Abstract
Conductive hydrogels are ideal materials for intelligent medical devices, human-machine interfaces, and flexible bioelectrodes due to their adjustable mechanical properties and electrical responsiveness, whereas it is still a great challenge to achieve the integration of excellent flexibility and biocompatibility into one hydrogel sensor while also incorporating self-healing, self-adhesion, environmental tolerance, and antimicrobial properties. Here, a nanocomposite conductive organohydrogel was constructed by using collagen (Col), alginate-derived carbon quantum dots (OSA-CQDs), poly(acrylic acid) (PAA), ethylene glycol reduced AgNPs, and Fe3+ ions. Depending on OSA-CQDs with multiple chemical binding sites and high specific surface area as cross-linkers, while coupling highly biologically active Col chains and PAA chains are serving as an energy dissipation module, the resulting organohydrogel exhibited excellent flexibility (795% of strain, 193 kPa of strength), high cell compatibility (>95% survival rate), self-healing efficiency (HE = 79.5%), antifreezing (-20 °C), moisturizing (>120 h), repeatable adhesion (strength >20 kPa, times >10), inhibitory activity against Escherichia coli and Staphylococcus aureus (9 and 21.5 cm2), conductivity, and strain sensitivity (σ = 1.34 S/m, gauge factor (GF) = 11.63). Based on the all-in-one integration of multifunction, the organohydrogel can collaboratively adapt to the multimode of strain sensing and electrophysiological sensing to realize wireless real-time monitoring of human activities and physiological health. Therefore, this work provides a new and common platform for the design and sensing of next-generation hydrogel-based smart wearable sensors.
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Affiliation(s)
- Maohua Lan
- Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, Sichuan, China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, Sichuan, China
| | - Jinwei Zhang
- Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, Sichuan, China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, Sichuan, China
| | - Jin Zhou
- Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, Sichuan, China
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, Sichuan, China
| | - Haibin Gu
- Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, Sichuan, China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, Sichuan, China
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Hu J, Guo J, Zhao J, Chen Z, Kalulu M, Chen G, Fu G. Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method. ACS APPLIED MATERIALS & INTERFACES 2024; 16:10671-10681. [PMID: 38359324 DOI: 10.1021/acsami.3c17132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices.
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Affiliation(s)
- Jun Hu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province 211189, PR China
| | - Jiangping Guo
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Junyan Zhao
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Zixun Chen
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province 211189, PR China
| | - Mulenga Kalulu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province 211189, PR China
- Department of Chemistry, School of Natural Sciences, The University of Zambia, Lusaka 32379, Zambia
| | - Gaojian Chen
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Guodong Fu
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province 211189, PR China
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Liu J, Zhang X, Cui Y, Liu Y, Wang W, Guo Y, Wang Q, Dong X. Ionic Liquid/Water Binary Solvent Anti-Freezing Hydrogel for Strain and Temperature Sensors. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5208-5216. [PMID: 38236660 DOI: 10.1021/acsami.3c19136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Hydrogels are widely applied in the flexible wearable electronic devices field owing to their skin-like stretchability, superb biocompatibility, and high conductivity retention under mechanical deformations. Nevertheless, hydrogels are prone to freezing at low temperatures and losing water at high temperatures, which seriously limits their practical applications. Herein, a binary solvent system of ionic liquid (1-ethyl-3-methylimidazolium chloride) and water was prepared to endow the ionic hydrogel high ionic conductivity (0.28 S m-1 at 25 °C), high transparency (94.26%), and superior freezing tolerance (-50 °C). The multiple hydrogen bonds formed among polymer chains, water, and ionic liquids significantly improved the mechanical properties of the ionic hydrogel, enabling excellent tensile properties (strain >1800%) and durability (1000 times at 100% strain). Moreover, the ionic hydrogel was further assembled into a dual-response sensor, which exhibited satisfactory sensitivity to both tension (gauge factor = 2.15 at 200% strain) and temperature (temperature coefficient of resistance = -1.845%/°C) and can be applied for human motion and body temperature monitoring. This study provides a versatile method for preparing multifunctional hydrogels with a wide range of applications and lays the groundwork for human movement detection and smart health care.
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Affiliation(s)
- Jingying Liu
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211816, China
| | - Xinyi Zhang
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211816, China
| | - Ying Cui
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
| | - Yunlong Liu
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
| | - Wenjun Wang
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
| | - Yuxin Guo
- School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Qian Wang
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211816, China
| | - Xiaochen Dong
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211816, China
- School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou 221116, China
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Zhang J, Wang Y, Wei Q, Li M, Chen X. 3D printable, stretchable, anti-freezing and rapid self-healing organogel-based sensors for human motion detection. J Colloid Interface Sci 2024; 653:1514-1525. [PMID: 37804619 DOI: 10.1016/j.jcis.2023.09.183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/09/2023]
Abstract
Self-healing hydrogels have promising applications in sensors and wearable devices. However, self-healing hydrogels prepared with water as the dispersion medium inevitably freeze at sub-zero temperature, resulting in a loss of the self-healing and sensing ability. The black phosphorene / ethylene glycol / polyvinyl alcohol / sodium tetraborate / sodium alginate (BP/EG-SPB) organogels were prepared by 3D printing technology and solvent displacement method. The organogel exhibits high stretchability (1900 % strain), excellent self-healing property (25 s) and outstanding anti-freezing property (lower than -120 °C freezing point). Furthermore, the organogel can rapidly self-healed (150 s) at a low temperature (-80 °C) without any external stimulation. Additionally, this organogel-based flexible sensor possesses excellent sensitivity (gauge factor: 28.66 at 1900 % strain) and fast response capability, allowing for effective detection of human motion. This work provides a novel method for preparing multifunctional organogel-based sensors for use in harsh climates.
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Affiliation(s)
- Juan Zhang
- Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China; Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yanen Wang
- Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China; Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi'an 710072, China.
| | - Qinghua Wei
- Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China; Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi'an 710072, China.
| | - Mingyang Li
- Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China; Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xiaohu Chen
- Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China; Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi'an 710072, China
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Zhao R, Zhao Z, Song S, Wang Y. Multifunctional Conductive Double-Network Hydrogel Sensors for Multiscale Motion Detection and Temperature Monitoring. ACS APPLIED MATERIALS & INTERFACES 2023; 15:59854-59865. [PMID: 38095585 DOI: 10.1021/acsami.3c15522] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
As typical soft materials, hydrogels have demonstrated great potential for the fabrication of flexible sensors due to their highly compatible elastic modulus with human skin, prominent flexibility, and biocompatible three-dimensional network structure. However, the practical application of wearable hydrogel sensors is significantly constrained because of weak adhesion, limited stretchability, and poor self-healing properties of traditional hydrogels. Herein, a multifunctional sodium hyaluronate (SH)/borax (B)/gelatin (G) double-cross-linked conductive hydrogel (SBG) was designed and constructed through a simple one-pot blending strategy with SH and gelatin as the gel matrix and borax as the dynamic cross-linker. The obtained SBG hydrogels exhibited a moderate tensile strength of 25.3 kPa at a large elongation of 760%, high interfacial toughness (106.5 kJ m-3), strong adhesion (28 kPa to paper), and satisfactory conductivity (224.5 mS/m). In particular, the dynamic cross-linking between SH, gelatin, and borax via borate ester bonds and hydrogen bonds between SH and gelatin chain endowed the SBG hydrogels with good fatigue resistance (>300 cycles), rapid self-healing performance (HE (healing efficiency) ∼97.03%), and excellent repeatable adhesion. The flexible wearable sensor assembled with SBG hydrogels demonstrated desirable strain sensing performance with a competitive gauge factor and exceptional stability, which enabled it to detect and distinguish various multiscale human motions and physiological signals. Furthermore, the flexible sensor is capable of precisely perceiving temperature variation with a high thermal sensitivity (1.685% °C-1). As a result, the wearable sensor displayed dual sensory performance for temperature and strain deformation. It is envisioned that the integration of strain sensors and thermal sensors provide a novel and convenient strategy for the next generation of multisensory wearable electronics and lay a solid foundation for their application in electronic skin and soft actuators.
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Affiliation(s)
- Rongrong Zhao
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, P. R. China
| | - Zengdian Zhao
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, P. R. China
| | - Shasha Song
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, P. R. China
| | - Yifan Wang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore639798, Singapore
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Seesaard T, Wongchoosuk C. Flexible and Stretchable Pressure Sensors: From Basic Principles to State-of-the-Art Applications. MICROMACHINES 2023; 14:1638. [PMID: 37630177 PMCID: PMC10456594 DOI: 10.3390/mi14081638] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Flexible and stretchable electronics have emerged as highly promising technologies for the next generation of electronic devices. These advancements offer numerous advantages, such as flexibility, biocompatibility, bio-integrated circuits, and light weight, enabling new possibilities in diverse applications, including e-textiles, smart lenses, healthcare technologies, smart manufacturing, consumer electronics, and smart wearable devices. In recent years, significant attention has been devoted to flexible and stretchable pressure sensors due to their potential integration with medical and healthcare devices for monitoring human activity and biological signals, such as heartbeat, respiratory rate, blood pressure, blood oxygen saturation, and muscle activity. This review comprehensively covers all aspects of recent developments in flexible and stretchable pressure sensors. It encompasses fundamental principles, force/pressure-sensitive materials, fabrication techniques for low-cost and high-performance pressure sensors, investigations of sensing mechanisms (piezoresistivity, capacitance, piezoelectricity), and state-of-the-art applications.
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Affiliation(s)
- Thara Seesaard
- Department of Physics, Faculty of Science and Technology, Kanchanaburi Rajabhat University, Kanchanaburi 71190, Thailand;
| | - Chatchawal Wongchoosuk
- Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
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