scholarly journals Carbon/Silicone Nanocomposite-Enabled Soft Pressure Sensors with a Liquid-Filled Cell Structure Design for Low Pressure Measurement

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4732
Author(s):  
Fei Wang ◽  
Xiaoming Tao
Keyword(s):  
Pressure Measurement ◽  
Cell Structure ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Humanoid Robots ◽  
Low Pressure ◽  
Measurement Range ◽  
Structure Design ◽  
Wearable Electronics ◽  
Minimal Resistance

In the fields of humanoid robots, soft robotics, and wearable electronics, the development of artificial skins entails pressure sensors that are low in modulus, high in sensitivity, and minimal in hysteresis. However, few sensors in the literature can meet all the three requirements, especially in the low pressure range (<10 kPa). This article presents a design for such pressure sensors. The bioinspired liquid-filled cell-type structural design endows the sensor with appropriate softness (Young’s modulus < 230 kPa) and high sensitivity (highest at 0.7 kPa−1) to compression forces below 0.65 N (6.8 kPa). The low-end detection limit is ~0.0012 N (13 Pa), only triple the mass of a bee. Minimal resistance hysteresis of the pressure sensor is 7.7%. The low hysteresis is attributed to the study on the carbon/silicone nanocomposite, which reveals the effect of heat treatment on its mechanical and electromechanical hysteresis. Pressure measurement range and sensitivity of the sensor can be tuned by changing the structure and strain gauge parameters. This concept of sensor design, when combined with microfluidics technology, is expected to enable soft, stretchable, and highly precise touch-sensitive artificial skins.

scholarly journals Nanocomposite-Based Microstructured Piezoresistive Pressure Sensors for Low-Pressure Measurement Range

Micromachines ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 43 ◽  
Author(s):  
Vasileios Mitrakos ◽  
Philip Hands ◽  
Gerard Cummins ◽  
Lisa Macintyre ◽  
Fiona Denison ◽  
...  
Keyword(s):  
Pressure Measurement ◽  
Pressure Sensors ◽  
Low Pressure ◽  
Measurement Range ◽  
Piezoresistive Pressure Sensors

scholarly journals Flexible Ultra-Thin Nanocomposite Based Piezoresistive Pressure Sensors for Foot Pressure Distribution Measurement

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6082
Author(s):  
Dhivakar Rajendran ◽  
Rajarajan Ramalingame ◽  
Saravanan Palaniyappan ◽  
Guntram Wagner ◽  
Olfa Kanoun
Keyword(s):  
Pressure Distribution ◽  
Pressure Measurement ◽  
Low Cost ◽  
Measurement Techniques ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Measurement Range ◽  
Experimental Investigations ◽  
Healthcare Applications ◽  
Foot Pressure

Foot pressure measurement plays an essential role in healthcare applications, clinical rehabilitation, sports training and pedestrian navigation. Among various foot pressure measurement techniques, in-shoe sensors are flexible and can measure the pressure distribution accurately. In this paper, we describe the design and characterization of flexible and low-cost multi-walled carbon nanotubes (MWCNT)/Polydimethylsiloxane (PDMS) based pressure sensors for foot pressure monitoring. The sensors have excellent electrical and mechanical properties an show a stable response at constant pressure loadings for over 5000 cycles. They have a high sensitivity of 4.4 kΩ/kPa and the hysteresis effect corresponds to an energy loss of less than 1.7%. The measurement deviation is of maximally 0.13% relative to the maximal relative resistance. The sensors have a measurement range of up to 330 kPa. The experimental investigations show that the sensors have repeatable responses at different pressure loading rates (5 N/s to 50 N/s). In this paper, we focus on the demonstration of the functionality of an in-sole based on MWCNT/PDMS nanocomposite pressure sensors, weighing approx. 9.46 g, by investigating the foot pressure distribution while walking and standing. The foot pressure distribution was investigated by measuring the resistance changes of the pressure sensors for a person while walking and standing. The results show that pressure distribution is higher in the forefoot and the heel while standing in a normal position. The foot pressure distribution is transferred from the heel to the entire foot and further transferred to the forefoot during the first instance of the gait cycle.

scholarly journals Fiber-junction design for directional bending sensors

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhundong Li ◽  
Fengming Hu ◽  
Zhiming Chen ◽  
Jingcheng Huang ◽  
Guoning Chen ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Human Motion ◽  
Structure Design ◽  
Theoretical Expression ◽  
Wearable Electronics ◽  
Materials Synthesis ◽  
Conductive Fiber ◽  
Flexible Printed Circuit ◽  
Fiber Materials ◽  
Human Motion Monitoring

AbstractFlexible sensors in wearable electronics have become increasingly multifunctional due to the development of materials synthesis and structure design. In particular, structural design can not only add capabilities to sensors fabricated from existing available and normal materials, but also offer opportunities for the fabrication of sensors with certain desired functions. Here, we designed a series of fiber-junction structure models, in which two fibers were simply hooked to each other to form a junction on a flexible printed circuit, for fabrication of directional bending sensors. The value and direction of bending angle are related to the change in electronic signal by a theoretical expression, allowing us to employ a simple and practicable method to use available conductive fiber materials to fabricate high-sensitivity, high-resolution and directional bending sensors. In addition, these models are generally applicable, which have broad combination with different conductive fiber, and corresponding bending sensors all possess capability of directional identification. Furthermore, the capability of identifying directional bending was demonstrated by human motion monitoring such as joint bending and muscle contraction.

Development Of PVDF Thick Film Interdigitated Capacitors For Pressure Measurement On Flexible Melinex Substrates

2005 ◽  
Vol 870 ◽  
Author(s):  
Arous Arshak ◽  
Khalil Arshak ◽  
Deirdre Morris ◽  
Olga Korostynska ◽  
Essa Jafer
Keyword(s):  
Polymer Film ◽  
Thick Film ◽  
Pressure Measurement ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Strain Gauges ◽  
Interdigitated Electrodes ◽  
Higher Sensitivity

AbstractIn this work, a PVDF thick film paste was deposited onto interdigitated electrodes to form a capacitor. Two different substrates, alumina and Melinex® were used. Capacitors, fabricated on alumina substrates were tested as strain gauges, and showed a high sensitivity with low hysteresis. Capacitors on Melinex® substrates were tested as pressure sensors by adhering them to planar and cylindrical surfaces and subjecting them to pressures up to 300 kPa. Their sensitivity and hysteresis during cycling were examined and compared. It was found that sensors on cylindrical surfaces showed a higher sensitivity, however the hysteresis was also increased. It is thought that this is due to instabilities in the polymer film, accentuated by stretching of the substrate.

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 Design, Manufacture and Testing of Capacitive Pressure Sensors for Low-Pressure Measurement Ranges

Micromachines ◽  
2017 ◽  
Vol 8 (2) ◽  
pp. 41 ◽  
Author(s):  
Vasileios Mitrakos ◽  
Lisa Macintyre ◽  
Fiona Denison ◽  
Philip Hands ◽  
Marc Desmulliez
Keyword(s):  
Pressure Measurement ◽  
Pressure Sensors ◽  
Low Pressure

scholarly journals Highly-Sensitive Textile Pressure Sensors Enabled by Suspended-Type All Carbon Nanotube Fiber Transistor Architecture

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1103
Author(s):  
Jae Sang Heo ◽  
Keon Woo Lee ◽  
Jun Ho Lee ◽  
Seung Beom Shin ◽  
Jeong Wan Jo ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Pressure Sensor ◽  
Pressure Range ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Low Pressure ◽  
Electronic Textiles ◽  
Carbon Nanotube Fiber ◽  
Cnt Fiber ◽  
Walled Carbon Nanotubes

Among various wearable health-monitoring electronics, electronic textiles (e-textiles) have been considered as an appropriate alternative for a convenient self-diagnosis approach. However, for the realization of the wearable e-textiles capable of detecting subtle human physiological signals, the low-sensing performances still remain as a challenge. In this study, a fiber transistor-type ultra-sensitive pressure sensor (FTPS) with a new architecture that is thread-like suspended dry-spun carbon nanotube (CNT) fiber source (S)/drain (D) electrodes is proposed as the first proof of concept for the detection of very low-pressure stimuli. As a result, the pressure sensor shows an ultra-high sensitivity of ~3050 Pa−1 and a response/recovery time of 258/114 ms in the very low-pressure range of <300 Pa as the fiber transistor was operated in the linear region (VDS = −0.1 V). Also, it was observed that the pressure-sensing characteristics are highly dependent on the contact pressure between the top CNT fiber S/D electrodes and the single-walled carbon nanotubes (SWCNTs) channel layer due to the air-gap made by the suspended S/D electrode fibers on the channel layers of fiber transistors. Furthermore, due to their remarkable sensitivity in the low-pressure range, an acoustic wave that has a very tiny pressure could be detected using the FTPS.

scholarly journals Flexible Ecoflex®/Graphene Nanoplatelet Foams for Highly Sensitive Low-Pressure Sensors

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4406
Author(s):  
Marco Fortunato ◽  
Irene Bellagamba ◽  
Alessio Tamburrano ◽  
Maria Sabrina Sarto
Keyword(s):  
High Performance ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Cost Effective ◽  
Low Pressure ◽  
Human Motion ◽  
Compression Tests ◽  
Piezoresistive Sensors ◽  
Human Motion Detection ◽  
Pressure Regime

The high demand for multifunctional devices for smart clothing applications, human motion detection, soft robotics, and artificial electronic skins has encouraged researchers to develop new high-performance flexible sensors. In this work, we fabricated and tested new 3D squeezable Ecoflex® open cell foams loaded with different concentrations of graphene nanoplatelets (GNPs) in order to obtain lightweight, soft, and cost-effective piezoresistive sensors with high sensitivity in a low-pressure regime. We analyzed the morphology of the produced materials and characterized both the mechanical and piezoresistive response of samples through quasi-static cyclic compression tests. Results indicated that sensors infiltrated with 1 mg of ethanol/GNP solution with a GNP concentration of 3 mg/mL were more sensitive and stable compared to those infiltrated with the same amount of ethanol/GNP solution but with a lower GNP concentration. The electromechanical response of the sensors showed a negative piezoresistive behavior up to ~10 kPa and an opposite trend for the 10–40 kPa range. The sensors were particularly sensitive at very low deformations, thus obtaining a maximum sensitivity of 0.28 kPa−1 for pressures lower than 10 kPa.

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.

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