scholarly journals Carbonized Cotton Fabric-Based Flexible Capacitive Pressure Sensor Using a Porous Dielectric Layer with Tilted Air Gaps

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3895
Author(s):  
Yelin Ko ◽  
Chi Cuong Vu ◽  
Jooyong Kim
Keyword(s):  
Cotton Fabric ◽  
Pressure Sensor ◽  
Low Cost ◽  
Pressure Sensors ◽  
Capacitive Pressure Sensor ◽  
Wearable Electronics ◽  
Detection Range ◽  
Air Gaps ◽  
Wide Range ◽  
Knitted Structure

Flexible and wearable pressure sensors have attracted significant attention owing to their roles in healthcare monitoring and human–machine interfaces. In this study, we introduce a wide-range, highly sensitive, stable, reversible, and biocompatible pressure sensor based on a porous Ecoflex with tilted air-gap-structured and carbonized cotton fabric (CCF) electrodes. The knitted structure of electrodes demonstrated the effectiveness of the proposed sensor in enhancing the pressure-sensing performance in comparison to a woven structure due to the inherent properties of naturally generated space. In addition, the presence of tilted air gaps in the porous elastomer provided high deformability, thereby significantly improving the sensor sensitivity compared to other dielectric structures that have no or vertical air gaps. The combination of knitted CCF electrodes and the porous dielectric with tilted air gaps achieved a sensitivity of 24.5 × 10−3 kPa−1 at 100 kPa, along with a wide detection range (1 MPa). It is also noteworthy that this novel method is low-cost, facile, scalable, and ecofriendly. Finally, the proposed sensor integrated into a smart glove detected human motions of grasping water cups, thus demonstrating its potential applications in wearable electronics.

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.

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.

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.

scholarly journals Microdome-Tunable Graphene/Carbon Nanotubes Pressure Sensors Based on Polystyrene Array for Wearable Electronics

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7385
Author(s):  
Xingjie Su ◽  
Chunli Luo ◽  
Weiguo Yan ◽  
Junyi Jiao ◽  
Dongzhou Zhong
Keyword(s):  
Carbon Nanotubes ◽  
Pressure Sensor ◽  
Self Assembly ◽  
Low Cost ◽  
Pressure Sensors ◽  
Conductive Filler ◽  
Human Motion ◽  
Wearable Electronics ◽  
Flexible Pressure Sensor ◽  
Human Finger

Resistive pressure sensors are appealing due to having several advantages, such as simple reading mechanisms, simple construction, and quick dynamic response. Achieving a constantly changeable microstructure of sensing materials is critical for the flexible pressure sensor and remains a difficulty. Herein, a flexible, tunable resistive pressure sensors is developed via simple, low-cost microsphere self-assembly and graphene/carbon nanotubes (CNTs) solution drop coating. The sensor uses polystyrene (PS) microspheres to construct an interlocked dome microstructure with graphene/CNTs as a conductive filler. The results indicate that the interlocked microdome-type pressure sensor has better sensitivity than the single microdome-type and single planar-type without surface microstructure. The pressure sensor’s sensitivity can be adjusted by varying the diameter of PS microspheres. In addition, the resistance of the sensor is also tunable by adjusting the number of graphene/CNT conductive coating layers. The developed flexible pressure sensor effectively detected human finger bending, demonstrating tremendous potential in human motion monitoring.

scholarly journals Flexible and Transparent Pressure Sensor Based on CNTs Film Microstructure

2021 ◽  
Author(s):  
Liangliang Liu ◽  
Xin Yan
Keyword(s):  
Pressure Sensor ◽  
Production Cost ◽  
Composite Electrode ◽  
Pressure Sensors ◽  
Wearable Devices ◽  
Capacitive Pressure Sensor ◽  
Detection Range ◽  
Electronic Skin ◽  
Film Microstructure ◽  
Flexible Pressure Sensors

Abstract In recent years, capacitive flexible pressure sensors have been widely studied in electronic skin and wearable devices. The traditional capacitive pressure sensor has a higher production cost due to micro-nano machining technology such as lithography. This paper presents a flexible transparent capacitive pressure sensor based on a PDMS/CNT composite electrode, simple, transparent, flexible, and arrays without lithography. The sensitivity of the device has been tested to 0.0018 kpa -1 with a detection range of 0-30 kPa. The sensor is capable of rapidly detecting different pressures and remains stable after 100 load-unload tests.

Flexible Capacitive Pressure Sensors with Micro-Patterned Porous Dielectric Layer for Wearable Electronics

2022 ◽  
Author(s):  
Jing Wang ◽  
Longwei Li ◽  
Lanshuang Zhang ◽  
Panpan Zhang ◽  
Xiong Pu
Keyword(s):  
Pressure Sensor ◽  
Flexible Electronics ◽  
Dielectric Layer ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Capacitive Sensor ◽  
Human Motion ◽  
Capacitive Pressure Sensor ◽  
Wearable Electronics ◽  
Emulsified Water

Abstract Highly sensitive soft sensors play key roles in flexible electronics, which therefore have attracted much attention in recent years. Herein, we report a flexible capacitive pressure sensor with high sensitivity by using engineered micro-patterned porous polydimethylsiloxane (PDMS) dielectric layer through an environmental-friendly fabrication procedure. The porous structure is formed by evaporation of emulsified water droplets during PDMS curing process, while the micro-patterned structure is obtained via molding on sandpaper. Impressively, this structure renders the capacitive sensor with a high sensitivity up to 143.5 MPa-1 at the pressure range of 0.068~150 kPa and excellent anti-fatigue performance over 20,000 cycles. Meanwhile, the sensor can distinguish different motions of the same person or different people doing the same action. Our work illustrates the promising application prospects of this flexible pressure sensor for the security field or human motion monitoring area.

scholarly journals Skin-Inspired Pressure Sensor with MXene/P(VDF-TrFE-CFE) as Active Layer for Wearable Electronics

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 716
Author(s):  
Xiao-Quan Shen ◽  
Ming-Ding Li ◽  
Jun-Peng Ma ◽  
Qun-Dong Shen
Keyword(s):  
Active Layer ◽  
Pressure Sensor ◽  
Low Cost ◽  
High Sensitivity ◽  
Capacitive Pressure Sensor ◽  
Wearable Electronics ◽  
Electronic Skin ◽  
High Dielectric ◽  
Medical Analysis ◽  
Mechanical Sensing

Multi-functional electronic skin is of paramount significance for wearable electronics in health monitoring, medical analysis, and human-machine interfacing systems. In order to achieve the function of natural skin, mechanical sensing with high sensitivity is an important feature of electronic skin. Inspired by the spinosum structure under the skin, herein, we fabricate a new capacitive pressure sensor with two-dimensional transition-metal carbides and nitrides (MXene) and ferroelectric polymer (P(VDF-TrFE-CFE)) as an active layer and micropatterned Cr-Au deposited on polydimethylsiloxane as flexible electrodes. Such a method is facile, effective, easily operated, and low-cost. The device design provides great capacitive change as a consequence of large deformation under pressure. Benefiting from the randomly distributed microstructure and high dielectric constant of the active layer, the device demonstrates high sensitivity with great linearity (16.0 kPa−1 for less than 10 kPa), that is, a low detection limit of 8.9 Pa, and quick response. A series of dynamic physiological signals, including typing, knuckle motion, and voice recognition can be facilely detected, making it a competitive candidate in the field of wearable electronics.

A Capacitive MEMS Pressure Sensor With Wavy Membrane and Linear Capacitance-Pressure Response

2019 ◽  
Author(s):  
Stephen Oke ◽  
Mohammad Shavezipur
Keyword(s):  
Pressure Sensor ◽  
Ambient Pressure ◽  
Pressure Sensors ◽  
Wave Form ◽  
Capacitive Pressure Sensor ◽  
Working Pressure ◽  
Sensing Applications ◽  
Wide Range ◽  
Capacitance Pressure ◽  
Capacitive Mems

Abstract A novel structure for capacitive MEMS pressure sensors is presented that can be used for a wide range of pressure sensing applications. The sensor is designed such that its characteristic capacitance-pressure (C-P) response is highly linear and could cover a wide range of working pressure. A capacitive pressure sensor includes two capacitive electrodes, one patterned on the substrate and the other one suspended creating a sealed cavity. The suspended electrode acts as the pressure sensitive membrane in the device and undergoes out-of-plane deformation when there is a change in ambient pressure, resulting in a change in the device’s capacitance. The design presented in this work uses a wavy-shape membrane with controlled deformations to provide a highly linear C-P response. The wavy shape of the membrane can be fabricated using grey-scale mask and lithography. ANSYS APDL multiphysics solver is used to model and simulate the pressure sensor and optimize its response. The material used in the design and simulations of the pressure sensor is silicon carbide making this design suitable for harsh environment applications. The simulation results show that if the size and the shape of the wave form in the membrane are optimized, highly linear C-P response can be achieved and also its working pressure range can be extended.

Development of circuit solution and design of capacitive pressure sensor array for applied robotics

2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov
Keyword(s):  
Pressure Sensor ◽  
Output Signal ◽  
Sensor Array ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Fine Tuning ◽  
Capacitive Pressure Sensor ◽  
Cell Parameters ◽  
Linear Pattern ◽  
Sensor Structure

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

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