scholarly journals A High Sensitive Flexible Pressure Sensor Designed by Silver Nanowires Embedded in Polyimide (AgNW-PI)

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 206 ◽  
Author(s):  
Hongfang Li ◽  
Guifu Ding ◽  
Zhuoqing Yang

Silver nanowires (AgNW) have excellent electrical conductivity, transparency, and flexing endurance, and are broadly used in flexible electrodes and flexible sensors. This study mixed the silver nanowires and polyimide (PI) polymer using an in situ synthesis method, effectively reducing the problem of silver nanowires falling off the substrate. The selective wet etching method was firstly used to process the surface of AgNW-PI films, greatly enhancing the surface conductivity of AgNW-PI films. A flexible pressure sensor with high sensitivity was designed with two face-to-face AgNW-PI ultrathin layers. The experimental results show that our sensor presented a high sensitivity of about 1.3294 kPa−1 under a pressure of about 600 Pa, and when pressure continued to increase, the sensitivity decreased rapidly and reached saturation. Our flexible pressure sensor has the properties of low cost, high sensitivity, excellent repeatability, durability, and can detect various types of mechanical forces which could be utilized for flexible electronics.

2015 ◽  
Vol 748 ◽  
pp. 1-4 ◽  
Author(s):  
Li Xin Mo ◽  
Yu Qun Hou ◽  
Qing Bin Zhai ◽  
Wen Guan Zhang ◽  
Lu Hai Li

The novel flexible pressure sensor with skin-like stretchability and sensibility has attracted tremendous attention in academic and industrial world in recent years. And it also has demonstrated great potential in the applications of electronic skin and wearable devices. It is significant and challenging to develop a highly sensitive flexible pressure sensor with a simple, low energy consuming and low cost method. In this paper, the silver nanowires (AgNWs) as electrode material were synthesized by polyol process. The polydimethylsiloxane (PDMS) was chosen as a flexible substrate and polyimide (PI) film as dielectric layer. The AgNWs based electrode was prepared in two methods. One is coating the AgNWs on photographic paper followed by in situ PDMS curing. Another one is suction filtration of the AgNWs suspension followed by glass slide transfer and PDMS curing. Then the capacitive pressure sensor was packaged in a sandwich structure with two face to face electrodes and a PI film in the middle. The sensitivity of the sensor as well as the micro-structure of the electrodes was compared and studied. The results indicate that the roughness of the electrode based on AgNWs/PDMS micro-structure plays an important role in the sensitivity of sensor. The as-prepared flexible pressure sensor demonstrates high sensitivity of 0.65kPa-1. In addition, the fabrication method is simple, low energy consuming and low cost, which has great potential in the detection of pulse, heart rate, sound vibration and other tiny pressure.


NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950081 ◽  
Author(s):  
Wendan Jia ◽  
Qiang Zhang ◽  
Yongqiang Cheng ◽  
Dong Zhao ◽  
Yan Liu ◽  
...  

Flexible pressure sensors based on piezoresistive induction have recently become a research hotspot due to the simple device structure, low energy consumption, easy readout mechanism and excellent performance. For practical applications, flexible pressure sensors with both high sensitivity and low-cost mass production are highly desirable. Herein, this paper presents a high-sensitivity piezoresistive pressure sensor based on a micro-structured elastic electrode, which is low cost and can be mass-produced by a simple method of sandpaper molding. The micro-structure of the electrode surface under external pressure causes a change in the effective contact area and the distance between the electrodes, which exhibits great pressure sensitivity. The test results show that the surface structure is twice as sensitive as the planar structure under low pressure conditions. This is because of the special morphology of silver nanowires (AgNWs), which exhibits the tip of nanostructures on the surface and realizes the quantum tunneling mechanism. The sensor has high sensitivity for transmitting signals in real time and it can also be used to detect various contact actions. The low cost mass production and high sensitivity of flexible pressure sensors pave the way for electronic skin, wearable healthcare monitors and contact inspection applications.


Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 438 ◽  
Author(s):  
Youngsang Ko ◽  
Dabum Kim ◽  
Goomin Kwon ◽  
Jungmok You

Improved pressure sensing is of great interest to enable the next-generation of bioelectronics systems. This paper describes the development of a transparent, flexible, highly sensitive pressure sensor, having a composite sandwich structure of elastic silver nanowires (AgNWs) and poly(ethylene glycol) (PEG). A simple PEG photolithography was employed to construct elastic AgNW-PEG composite patterns on flexible polyethylene terephthalate (PET) film. A porous PEG hydrogel structure enabled the use of conductive AgNW patterns while maintaining the elasticity of the composite material, features that are both essential for high-performance pressure sensing. The transparency and electrical properties of AgNW-PEG composite could be precisely controlled by varying the AgNW concentration. An elastic AgNW-PEG composite hydrogel with 0.6 wt % AgNW concentration exhibited high transmittance including T550nm of around 86%, low sheet resistance of 22.69 Ω·sq−1, and excellent bending durability (only 5.8% resistance increase under bending to 10 mm radius). A flexible resistive pressure sensor based on our highly transparent AgNW-PEG composite showed stable and reproducible response, high sensitivity (69.7 kPa−1), low sensing threshold (~2 kPa), and fast response time (20–40 ms), demonstrating the effectiveness of the AgNW-PEG composite material as an elastic conductor.


Author(s):  
Jiang Zhao ◽  
Jiahao Gui ◽  
Jinsong Luo ◽  
Jing Gao ◽  
Caidong Zheng ◽  
...  

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.


2019 ◽  
Vol 294 ◽  
pp. 45-53 ◽  
Author(s):  
Shengnan Chang ◽  
Jin Li ◽  
Yin He ◽  
Hao Liu ◽  
Bowen Cheng

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1499 ◽  
Author(s):  
Young Jung ◽  
Kyung Kuk Jung ◽  
Dong Hwan Kim ◽  
Dong Hwa Kwak ◽  
Jong Soo Ko

We developed a simple, low-cost process to fabricate a flexible pressure sensor with linear sensitivity by using a porous carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite structure (CPCS). The working principle of this pressure sensor is based on the change in electrical resistance caused by the contact/non-contact of the CNT tip on the surface of the pores under pressure. The mechanical and electrical properties of the CPCSs could be quantitatively controlled by adjusting the concentration of CNTs. The fabricated flexible pressure sensor showed linear sensitivity and excellent performance with regard to repeatability, hysteresis, and reliability. Furthermore, we showed that the sensor could be applied for human motion detection, even when attached to curved surfaces.


Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6588
Author(s):  
Jun Ho Lee ◽  
Jae Sang Heo ◽  
Keon Woo Lee ◽  
Jae Cheol Shin ◽  
Jeong-Wan Jo ◽  
...  

For wearable health monitoring systems and soft robotics, stretchable/flexible pressure sensors have continuously drawn attention owing to a wide range of potential applications such as the detection of human physiological and activity signals, and electronic skin (e-skin). Here, we demonstrated a highly stretchable pressure sensor using silver nanowires (AgNWs) and photo-patternable polyurethane acrylate (PUA). In particular, the characteristics of the pressure sensors could be moderately controlled through a micro-patterned hole structure in the PUA spacer and size-designs of the patterned hole area. With the structural-tuning strategies, adequate control of the site-specific sensitivity in the range of 47~83 kPa−1 and in the sensing range from 0.1 to 20 kPa was achieved. Moreover, stacked AgNW/PUA/AgNW (APA) structural designed pressure sensors with mixed hole sizes of 10/200 µm and spacer thickness of 800 µm exhibited high sensitivity (~171.5 kPa−1) in the pressure sensing range of 0~20 kPa, fast response (100~110 ms), and high stretchability (40%). From the results, we envision that the effective structural-tuning strategy capable of controlling the sensing properties of the APA pressure sensor would be employed in a large-area stretchable pressure sensor system, which needs site-specific sensing properties, providing monolithic implementation by simply arranging appropriate micro-patterned hole architectures.


RSC Advances ◽  
2020 ◽  
Vol 10 (44) ◽  
pp. 26188-26196 ◽  
Author(s):  
Xiaojun Chen ◽  
Xitong Lin ◽  
Deyun Mo ◽  
Xiaoqun Xia ◽  
Manfeng Gong ◽  
...  

Bionic electronic skin with human sensory capabilities has attracted extensive research interest, which has been applied in the fields of medical health diagnosis, wearable electronics, human–computer interaction, and bionic prosthetics.


2020 ◽  
Vol 20 (13) ◽  
pp. 7354-7361
Author(s):  
Yaling Wang ◽  
Wei Zhu ◽  
Yuedong Yu ◽  
Pengcheng Zhu ◽  
Qingsong Song ◽  
...  

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