scholarly journals Highly Stretchable, Elastic, and Sensitive MXene-Based Hydrogel for Flexible Strain and Pressure Sensors

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Yao Lu ◽  
Xinyu Qu ◽  
Wen Zhao ◽  
Yanfang Ren ◽  
Weili Si ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Full Range ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Poly Vinyl Alcohol ◽  
Wearable Electronics ◽  
Double Network ◽  
Hydrogel Matrix ◽  
Highly Stretchable

Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition. However, it remains a challenge to fulfill the requirements on detecting full-range human activities with existing flexible strain sensors. Herein, highly stretchable, sensitive, and multifunctional flexible strain sensors based on MXene- (Ti3C2Tx-) composited poly(vinyl alcohol)/polyvinyl pyrrolidone double-network hydrogels were prepared. The uniformly distributed hydrophilic MXene nanosheets formed a three-dimensional conductive network throughout the hydrogel, endowing the flexible sensor with high sensitivity. The strong interaction between the double-network hydrogel matrix and MXene greatly improved the mechanical properties of the hydrogels. The resulting nanocomposited hydrogels featured great tensile performance (2400%), toughness, and resilience. Particularly, the as-prepared flexible pressure sensor revealed ultrahigh sensitivity (10.75 kPa-1) with a wide response range (0-61.5 kPa), fast response (33.5 ms), and low limit of detection (0.87 Pa). Moreover, the hydrogel-based flexible sensors, with high sensitivity and durability, could be employed to monitor full-range human motions and assembled into some aligned devices for subtle pressure detection, providing enormous potential in facial expression and phonation recognition, handwriting verification, healthy diagnosis, and wearable electronics.

scholarly journals Anisotropic, Wrinkled, and Crack-Bridging Structure for Ultrasensitive, Highly Selective Multidirectional Strain Sensors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Heng Zhang ◽  
Dan Liu ◽  
Jeng-Hun Lee ◽  
Haomin Chen ◽  
Eunyoung Kim ◽  
...  
Keyword(s):  
Rational Design ◽  
Full Range ◽  
Human Motion ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Trade Off ◽  
Human Motion Detection ◽  
Sensing Applications ◽  
Anisotropic Structures

AbstractFlexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications. Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities, existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity. Here, an ultrasensitive, highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers. The bilayer sensor consists of an aligned carbon nanotube (CNT) array assembled on top of a periodically wrinkled and cracked CNT–graphene oxide film. The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched, leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100% strain. The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3, to the benefit of accurate detection of loading directions by the multidirectional sensor. This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity, selectivity, and stretchability, demonstrating promising applications in full-range, multi-axis human motion detection for wearable electronics and smart robotics.

Highly responsive screen-printed asymmetric pressure sensor based on laser-induced graphene

2021 ◽  
Author(s):  
Jiang Zhao ◽  
Jiahao Gui ◽  
Jinsong Luo ◽  
Jing Gao ◽  
Caidong Zheng ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Screen Printing ◽  
Large Scale ◽  
Low Cost ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Integrated Sensor ◽  
Patterned Electrodes ◽  
Screen Printed

Abstract Graphene-based pressure sensors have received extensive attention in wearable devices. However, reliable, low-cost, and large-scale preparation of structurally stable graphene electrodes for flexible pressure sensors is still a challenge. Herein, for the first time, laser-induced graphene (LIG) powder are prepared into screen printing ink, and shape-controllable LIG patterned electrodes can be obtained on various substrates using a facile screen printing process, and a novel asymmetric pressure sensor composed of the resulting screen-printed LIG electrodes has been developed. Benefit from the 3D porous structure of LIG, the as-prepared flexible LIG screen-printed asymmetric pressure sensor has super sensing properties with a high sensitivity of 1.86 kPa−1, low detection limit of about 3.4 Pa, short response time, and long cycle durability. Such excellent sensing performances give our flexible asymmetric LIG screen-printed pressure sensor the ability to realize real-time detection of tiny body physiological movements (such as wrist pulse and pronunciation action). Besides, the integrated sensor array has a multi-touch function. This work could stimulate an appropriate approach to designing shape-controllable LIG screen-printed patterned electrodes on various flexible substrates to adapt the specific needs of fulfilling compatibility and modular integration for potential application prospects in wearable electronics.

scholarly journals Nano Carbon Black-Based High Performance Wearable Pressure Sensors

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 664 ◽  
Author(s):  
Junsong Hu ◽  
Junsheng Yu ◽  
Ying Li ◽  
Xiaoqing Liao ◽  
Xingwu Yan ◽  
...  
Keyword(s):  
Carbon Black ◽  
Pressure Sensor ◽  
High Performance ◽  
Large Scale ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Atmospheric Pollutant ◽  
Piezoresistive Pressure Sensor ◽  
Nano Carbon

The reasonable design pattern of flexible pressure sensors with excellent performance and prominent features including high sensitivity and a relatively wide workable linear range has attracted significant attention owing to their potential application in the advanced wearable electronics and artificial intelligence fields. Herein, nano carbon black from kerosene soot, an atmospheric pollutant generated during the insufficient burning of hydrocarbon fuels, was utilized as the conductive material with a bottom interdigitated textile electrode screen printed using silver paste to construct a piezoresistive pressure sensor with prominent performance. Owing to the distinct loose porous structure, the lumpy surface roughness of the fabric electrodes, and the softness of polydimethylsiloxane, the piezoresistive pressure sensor exhibited superior detection performance, including high sensitivity (31.63 kPa−1 within the range of 0–2 kPa), a relatively large feasible range (0–15 kPa), a low detection limit (2.26 pa), and a rapid response time (15 ms). Thus, these sensors act as outstanding candidates for detecting the human physiological signal and large-scale limb movement, showing their broad range of application prospects in the advanced wearable electronics field.

scholarly journals Flexible and Highly Sensitive Pressure Sensors Based on Microstructured Carbon Nanowalls Electrodes

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 496 ◽  
Author(s):  
Xi Zhou ◽  
Yongna Zhang ◽  
Jun Yang ◽  
Jialu Li ◽  
Shi Luo ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Limit Of Detection ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Physiological Signals ◽  
Healthcare Applications ◽  
Highly Sensitive ◽  
Carbon Nanowalls ◽  
Pressure Regime

Wearable pressure sensors have attracted widespread attention in recent years because of their great potential in human healthcare applications such as physiological signals monitoring. A desirable pressure sensor should possess the advantages of high sensitivity, a simple manufacturing process, and good stability. Here, we present a highly sensitive, simply fabricated wearable resistive pressure sensor based on three-dimensional microstructured carbon nanowalls (CNWs) embedded in a polydimethylsiloxane (PDMS) substrate. The method of using unpolished silicon wafers as templates provides an easy approach to fabricate the irregular microstructure of CNWs/PDMS electrodes, which plays a significant role in increasing the sensitivity and stability of resistive pressure sensors. The sensitivity of the CNWs/PDMS pressure sensor with irregular microstructures is as high as 6.64 kPa−1 in the low-pressure regime, and remains fairly high (0.15 kPa−1) in the high-pressure regime (~10 kPa). Both the relatively short response time of ~30 ms and good reproducibility over 1000 cycles of pressure loading and unloading tests illustrate the high performance of the proposed device. Our pressure sensor exhibits a superior minimal limit of detection of 0.6 Pa, which shows promising potential in detecting human physiological signals such as heart rate. Moreover, it can be turned into an 8 × 8 pixels array to map spatial pressure distribution and realize array sensing imaging.

scholarly journals Hierarchical network enabled flexible textile pressure sensors with ultra-high sensitivity, ultra-wide linearity and high-temperature resistance

2021 ◽  
Author(s):  
Meiling Jia ◽  
Chenghan Yi ◽  
Yankun Han ◽  
Xin Li ◽  
Guoliang Xu ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Pressure Sensor ◽  
High Performance ◽  
Full Range ◽  
Pressure Sensors ◽  
Fiber Surface ◽  
High Sensitivity ◽  
Harsh Environments ◽  
Point To Point

Abstract Thin, lightweight, and flexible textile pressure sensors with the ability to precisely detect the full range of faint pressure (< 100 Pa), low pressure (in the range of KPa) and high pressure (in the range of MPa) are in significant demand to meet the requirements for applications in daily activities and more meaningfully in some harsh environments, such as high temperature and high pressure. However, it is still a major challenge to fulfill these requirements simultaneously in a single pressure sensor. Herein, a high-performance pressure sensor enabled by polyimide fiber fabric with functionalized carbon-nanotube (PI/FCNT) is obtained via a facile electrophoretic deposition (EPD) approach. High-density FCNT is evenly wrapped and chemically bonded to the fiber surface during the EPD process, forming a conductive hierarchical fiber/FCNT matrix. Benefiting from the abundant yet firm contacting points, point-to-point contacting mode, and high elastic modulus of both PI and CNT, the proposed PI/FCNT pressure sensor exhibits ultra-high sensitivity (3.57 MPa− 1), ultra-wide linearity (3.24 MPa), exceptionally broad sensing range (~ 45 MPa), and long-term stability (> 4000 cycles). Furthermore, under a high working temperature of 200 ºC, the proposed sensor device still shows an ultra-high sensitivity of 2.64 MPa− 1 within a wide linear range of 7.2 MPa, attributing to its intrinsic high-temperature-resistant properties of PI and CNT. Thanks to these merits, the proposed PI/FCNT(EPD) pressure sensor could serve as an E-skin device to monitor the human physiological information, precisely detect tiny and extremely high pressure, and can be integrated into an intelligent mechanical hand to detect the contact force under high-temperature (> 300 ºC), endowing it with high applicability in the fields of real-time health monitoring, intelligent robots, and harsh environments.

scholarly journals High-Sensitivity Flexible Pressure Sensor-Based 3D CNTs Sponge for Human–Computer Interaction

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Pressure Sensors ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Wide Range ◽  
Flexible Pressure Sensors

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4,000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated.

Facile fabrication of highly sensitive and durable cotton fabric-based pressure sensors for motion and pulse monitoring

2021 ◽  
Author(s):  
Yinan Zhao ◽  
Lin Liu ◽  
zhen Li ◽  
Feifei Wang ◽  
Xinxin Chen ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Term Stability ◽  
Long Term Stability ◽  
Highly Sensitive ◽  
Facile Fabrication ◽  
Flexible Pressure Sensors

Design and development of flexible pressure sensors with high sensitivity, long-term stability and simple fabrication processes is a key procedure to fulfill the applications in wearable electronics, e-skin and medical...

scholarly journals Highly Stretchable and Self-Healing Strain Sensors Based on Nanocellulose-Supported Graphene Dispersed in Electro-Conductive Hydrogels

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 937 ◽  
Author(s):  
Chunxiao Zheng ◽  
Yiying Yue ◽  
Lu Gan ◽  
Xinwu Xu ◽  
Changtong Mei ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Cellulose Nanofibers ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Poly Vinyl Alcohol ◽  
Self Healing ◽  
Composite Gels ◽  
Highly Stretchable ◽  
Conductive Hydrogels ◽  
Pva Hydrogel

Intrinsic self-healing and highly stretchable electro-conductive hydrogels demonstrate wide-ranging utilization in intelligent electronic skin. Herein, we propose a new class of strain sensors prepared by cellulose nanofibers (CNFs) and graphene (GN) co-incorporated poly (vinyl alcohol)-borax (GN-CNF@PVA) hydrogel. The borax can reversibly and dynamically associate with poly (vinyl alcohol) (PVA) and GN-CNF nanocomplexes as a cross-linking agent, providing a tough and flexible network with the hydrogels. CNFs act as a bio-template and dispersant to support GN to create homogeneous GN-CNF aqueous dispersion, endowing the GN-CNF@PVA gels with promoted mechanical flexibility, strength and good conductivity. The resulting composite gels have high stretchability (break-up elongation up to 1000%), excellent viscoelasticity (storage modulus up to 3.7 kPa), rapid self-healing ability (20 s) and high healing efficiency (97.7 ± 1.2%). Due to effective electric pathways provided by GN-CNF nanocomplexes, the strain sensors integrated by GN-CNF@PVA hydrogel with good responsiveness, stability and repeatability can efficiently identify and monitor the various human motions with the gauge factor (GF) of about 3.8, showing promising applications in the field of wearable sensing devices.

A capacitive sensor using resin thermoplastic elastomer and carbon fibers for monitoring pressure distribution

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guanzheng Wu ◽  
Siming Li ◽  
Jiayu Hu ◽  
Manchen Dong ◽  
Ke Dong ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fibers ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Thermoplastic Elastomer ◽  
Gauge Factor ◽  
Capacitive Pressure Sensor ◽  
Wearable Electronics ◽  
Content Type

Purpose This paper aims to study the working principle of the capacitive pressure sensor and explore the distribution of pressure acting on the surface of the capacitor. Herein, a kind of high sensitivity capacitive pressure sensor was prepared by overlaying carbon fibers (CFs) on the surfaces of the thermoplastic elastomer (TPE), the TPE with high elasticity is a dielectric elastomer for the sensor and the CFs with excellent electrical conductivity were designed as the conductor. Design/methodology/approach Due to the excellent mechanical properties and electrical conductivity of CFs, it was designed as the conductor layer for the TPE/CFs capacitive pressure sensor via laminating CFs on the surfaces of the columnar TPE. Then, a ‘#' type structure of the capacitive pressure sensor was designed and fabricated. Findings The ‘#' type of capacitive pressure sensor of TPE/CFs composite was obtained in high sensitivity with a gauge factor of 2.77. Furthermore, the change of gauge factor values of the sensor under 10 per cent of applied strains was repeated for 1,000 cycles, indicating its outstanding sensing stability. Moreover, the ‘#' type capacitive pressure sensor of TPE/CFs was consisted of several capacitor arrays via laminating CFs, which could detect the distribution of pressure. Research limitations/implications The TPE/CFs capacitive pressure sensor was easily fabricated with high sensitivity and quick responsiveness, which is desirably applied in wearable electronics, robots, medical devices, etc. Originality/value The outcome of this study will help to fabricate capacitive pressure sensors with high sensitivity and outstanding sensing stability.

Ultra-stretchable and highly sensitive strain sensor based on gradient structure carbon nanotubes

Nanoscale ◽  
2018 ◽  
Vol 10 (28) ◽  
pp. 13599-13606 ◽  
Author(s):  
Binghao Liang ◽  
Zhiqiang Lin ◽  
Wenjun Chen ◽  
Zhongfu He ◽  
Jing Zhong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Gauge Factor ◽  
Gradient Structure ◽  
Highly Sensitive ◽  
Highly Stretchable

A highly stretchable and sensitive strain sensor based on a gradient carbon nanotube was developed. The strain sensors show an unprecedented combination of both high sensitivity (gauge factor = 13.5) and ultra-stretchability (>550%).

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