scholarly journals A Soft Pressure Sensor Array Based on a Conducting Nanomembrane

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 933
Author(s):  
Daekwang Jung ◽  
Kyumin Kang ◽  
Hyunjin Jung ◽  
Duhwan Seong ◽  
Soojung An ◽  
...  

Although skin-like pressure sensors exhibit high sensitivity with a high performance over a wide area, they have limitations owing to the critical issue of being linear only in a narrow strain range. Various strategies have been proposed to improve the performance of soft pressure sensors, but such a nonlinearity issue still exists and the sensors are only effective within a very narrow strain range. Herein, we fabricated a highly sensitive multi-channel pressure sensor array by using a simple thermal evaporation process of conducting nanomembranes onto a stretchable substrate. A rigid-island structure capable of dissipating accumulated strain energy induced by external mechanical stimuli was adopted for the sensor. The performance of the sensor was precisely controlled by optimizing the thickness of the stretchable substrate and the number of serpentines of an Au membrane. The fabricated sensor exhibited a sensitivity of 0.675 kPa−1 in the broad pressure range of 2.3–50 kPa with linearity (~0.990), and good stability (>300 Cycles). Finally, we successfully demonstrated a mapping of pressure distribution.

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 496 ◽  
Author(s):  
Xi Zhou ◽  
Yongna Zhang ◽  
Jun Yang ◽  
Jialu Li ◽  
Shi Luo ◽  
...  

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.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 664 ◽  
Author(s):  
Junsong Hu ◽  
Junsheng Yu ◽  
Ying Li ◽  
Xiaoqing Liao ◽  
Xingwu Yan ◽  
...  

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.


Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1412 ◽  
Author(s):  
Young Jung ◽  
Wookjin Lee ◽  
Kyungkuk Jung ◽  
Byunggeon Park ◽  
Jinhyoung Park ◽  
...  

In recent times, polymer-based flexible pressure sensors have been attracting a lot of attention because of their various applications. A highly sensitive and flexible sensor is suggested, capable of being attached to the human body, based on a three-dimensional dielectric elastomeric structure of polydimethylsiloxane (PDMS) and microsphere composite. This sensor has maximal porosity due to macropores created by sacrificial layer grains and micropores generated by microspheres pre-mixed with PDMS, allowing it to operate at a wider pressure range (~150 kPa) while maintaining a sensitivity (of 0.124 kPa−1 in a range of 0~15 kPa) better than in previous studies. The maximized pores can cause deformation in the structure, allowing for the detection of small changes in pressure. In addition to exhibiting a fast rise time (~167 ms) and fall time (~117 ms), as well as excellent reproducibility, the fabricated pressure sensor exhibits reliability in its response to repeated mechanical stimuli (2.5 kPa, 1000 cycles). As an application, we develop a wearable device for monitoring repeated tiny motions, such as the pulse on the human neck and swallowing at the Adam’s apple. This sensory device is also used to detect movements in the index finger and to monitor an insole system in real-time.


2021 ◽  
Author(s):  
Meiling Jia ◽  
Chenghan Yi ◽  
Yankun Han ◽  
Xin Li ◽  
Guoliang Xu ◽  
...  

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.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun

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.


Nanoscale ◽  
2021 ◽  
Author(s):  
Yachu Zhang ◽  
Han Lin ◽  
Fei Meng ◽  
Huai Liu ◽  
David Mesa ◽  
...  

Wearable and highly sensitive pressure sensors are of great importance for robotics, health monitoring and biomedical applications. Simultaneously achieving high sensitivity within a broad working range, fast response time (within...


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 442
Author(s):  
Kyobin Keum ◽  
Jae Sang Heo ◽  
Jimi Eom ◽  
Keon Woo Lee ◽  
Sung Kyu Park ◽  
...  

Textile-based pressure sensors have garnered considerable interest in electronic textiles due to their diverse applications, including human–machine interface and healthcare monitoring systems. We studied a textile-based capacitive pressure sensor array using a poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP)/ionic liquid (IL) composite film. By constructing a capacitor structure with Ag-plated conductive fiber electrodes that are embedded in fabrics, a capacitive pressure sensor showing high sensitivity, good operation stability, and a wide sensing range could be created. By optimizing the PVDF-HFP:IL ratio (6.5:3.5), the fabricated textile pressure sensors showed sensitivity of 9.51 kPa−1 and 0.69 kPa−1 in the pressure ranges of 0–20 kPa and 20–100 kPa, respectively. The pressure-dependent capacitance variation in our device was explained based on the change in the contact-area formed between the multi-filament fiber electrodes and the PVDF-HFP/IL film. To demonstrate the applicability and scalability of the sensor device, a 3 × 3 pressure sensor array was fabricated. Due to its matrix-type array structure and capacitive sensing mechanism, multi-point detection was possible, and the different positions and the weights of the objects could be identified.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ruzhan Qin ◽  
Mingjun Hu ◽  
Xin Li ◽  
Te Liang ◽  
Haoyi Tan ◽  
...  

AbstractThe development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices, but it is still a great challenge to fabricate capacitive sensors with high sensitivity. Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors. In this work, a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone (PVP) by an interdigital electrode is reported. By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer, the sensitivity of the capacitive sensor can be improved. The capacitive sensor based on MXene/PVP here has a high sensitivity (~1.25 kPa−1), low detection limit (~0.6 Pa), wide sensing range (up to 294 kPa), fast response and recovery times (~30/15 ms) and mechanical stability of 10000 cycles. The presented sensor here can be used for various pressure detection applications, such as finger pressing, wrist pulse measuring, breathing, swallowing and speech recognition. This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.


Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2406 ◽  
Author(s):  
Xinran Tang ◽  
Yihui Miao ◽  
Xinjian Chen ◽  
Baoqing Nie

There is a rapid growing demand for highly sensitive, easy adaptive and low-cost pressure sensing solutions in the fields of health monitoring, wearable electronics and home care. Here, we report a novel flexible inductive pressure sensor array with ultrahigh sensitivity and a simple construction, for large-area contact pressure measurements. In general, the device consists of three layers: a planar spiral inductor layer and ferrite film units attached on a polyethylene terephthalate (PET) membrane, which are separated by an array of elastic pillars. Importantly, by introducing the ferrite film with an excellent magnetic permeability, the effective permeability around the inductor is greatly influenced by the separation distance between the inductor and the ferrite film. As a result, the value of the inductance changes largely as the separation distance varies as an external load applies. Our device has achieved an ultrahigh sensitivity of 1.60 kPa−1 with a resolution of 13.61 Pa in the pressure range of 0–0.18 kPa, which is comparable to the current state-of-the-art flexible pressure sensors. More remarkably, our device shows an outstanding stability when exposed to environmental interferences, e.g., electrical noises from skin surfaces (within 0.08% variations) and a constant pressure load for more than 32 h (within 0.3% variations). In addition, the device exhibits a fast response time of 111 ms and a good repeatability under cyclic pressures varying from 38.45 to 177.82 Pa. To demonstrate its practical usage, we have successfully developed a 4 × 4 inductive pressure sensor array into a wearable keyboard for a smart electronic calendar application.


2017 ◽  
Vol 5 (42) ◽  
pp. 11018-11024 ◽  
Author(s):  
Jie Xue ◽  
Jiawei Chen ◽  
Jizhong Song ◽  
Leimeng Xu ◽  
Haibo Zeng

A high-performance and tailorable pressure sensor based on the Zn2GeO4@PPy nanowire aerogel for applications in visual and wearable fields has been developed and show high sensitivity of the pressure sensor (0.38 kPa−1at pressure regions less than 1.5 kPa). We also combined the aerogels with Light Emitting Diode which make a visible sensor come true.


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