scholarly journals Stretchable Pressure Sensor with Leakage-Free Liquid-Metal Electrodes

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1316 ◽  
Author(s):  
Lunjia Zhang ◽  
Meng Gao ◽  
Ronghang Wang ◽  
Zhongshan Deng ◽  
Lin Gui
Keyword(s):  
High Pressure ◽  
Liquid Metal ◽  
Pressure Sensors ◽  
Soft Materials ◽  
Metal Electrode ◽  
Wearable Electronics ◽  
Foot Pressure ◽  
External Interference ◽  
Pressure Sensing ◽  
Wide Range

Nowadays, with the development of wearable devices, stretchable pressure sensors have been widely adopted in all kinds of areas. Most of the sensors aim to detect small pressure, such as fingertip tactile sensing, but only a few are focused on high-pressure sensing, such as foot pressure sensing during men’s walking. In this work, a liquid metal-based stretchable sensor for large-pressure measurement is investigated. This sensor is fully stretchable because it is made of soft materials. However, when the soft sensor is subjected to high pressure, the liquid metal easily leaks from microchannels because it maintains the liquid state at room temperature. We therefore propose to fabricate liquid metal-based leakage-free electrodes to handle the liquid-metal leak. Parametric studies are conducted to compare this sensor with liquid-metal-only electrodes and leakage-free electrodes. The leakage-free electrodes increase the measurement ranges from 0.18, 0.18, and 0.15 MPa to 0.44 MPa, with higher linearity and precision. The improvement in the liquid-metal electrode enables the sensors to work stably within 0.44 MPa pressure and 20% strain. In addition, we integrate two capacitors, namely, a working capacitor and a reference capacitor, into one sensor to reduce the influence of parasitic capacitance brought about by external interference. This stretchable capacitive sensor capable of working under a wide range of pressure with good repeatability, sensitivity, and linearity, exhibits great potential use for wearable electronics. Finally, the method for fabricating leakage-free electrodes shows great value for hyperelastic electronics manufacturing and micromachine technology.

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.

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.

ТЕХНОЛОГИЯ И ПРИМЕНЕНИЕ ЭЛЕКТРОХИМИЧЕСКИХ ПРЕОБРАЗОВАТЕЛЕЙ

2020 ◽  
Vol 96 (3s) ◽  
pp. 450-455
Author(s):  
В.Г. Криштоп ◽  
Д.А. Жевненко ◽  
П.В. Дудкин ◽  
Е.С. Горнев ◽  
В.Г. Попов ◽  
...  
Keyword(s):  
Pressure Sensors ◽  
Engineering Applications ◽  
Electrochemical Systems ◽  
Seismic Sensors ◽  
Microelectronic Technology ◽  
Wide Range ◽  
Electrochemical Transducers ◽  
Element Base ◽  
New Devices

Электрохимические системы очень перспективны для разработки новой элементной базы для микроэлектроники и для использования в широком спектре инженерных задач. Мы разработали новую микроэлектронную технологию для изготовления электрохимических преобразователей (ЭХП) и новые приборы на основе новых электрохимических микроэлектронных чипов. Планарные электрохимические преобразователи могут использоваться в акселерометрах, сейсмических датчиках, датчиках вращения, гидрофонах и датчиках давления. Electrochemical systems are very promising for the development of a new element base for microelectronics, and for use in a wide range of engineering applications. We have developed a new microelectronic technology for manufacturing electrochemical transducers (ECP) and new devices based on new electrochemical microelectronic chips. Planar electrochemical transducers are used in accelerometers, seismic sensors, rotation sensors, hydrophones and pressure sensors.

scholarly journals Simulation and Nonlinearity Optimization of a High-Pressure Sensor

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4419
Author(s):  
Ting Li ◽  
Haiping Shang ◽  
Weibing Wang
Keyword(s):  
High Pressure ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Original Model ◽  
Ansys Software ◽  
Nonlinear Error ◽  
Sensor Model ◽  
Optimized Model ◽  
Simulation Results ◽  
Better Than

A pressure sensor in the range of 0–120 MPa with a square diaphragm was designed and fabricated, which was isolated by the oil-filled package. The nonlinearity of the device without circuit compensation is better than 0.4%, and the accuracy is 0.43%. This sensor model was simulated by ANSYS software. Based on this model, we simulated the output voltage and nonlinearity when piezoresistors locations change. The simulation results showed that as the stress of the longitudinal resistor (RL) was increased compared to the transverse resistor (RT), the nonlinear error of the pressure sensor would first decrease to about 0 and then increase. The theoretical calculation and mathematical fitting were given to this phenomenon. Based on this discovery, a method for optimizing the nonlinearity of high-pressure sensors while ensuring the maximum sensitivity was proposed. In the simulation, the output of the optimized model had a significant improvement over the original model, and the nonlinear error significantly decreased from 0.106% to 0.0000713%.

scholarly journals Recent Advances in Liquid Metal Based Wearable Electronics and Materials

iScience ◽  
2021 ◽  
pp. 102698
Author(s):  
Phillip Won ◽  
Seongmin Jeong ◽  
Carmel Majidi ◽  
Seung Hwan Ko
Keyword(s):  
Liquid Metal ◽  
Wearable Electronics ◽  
Recent Advances

CMOS-MEMS Based Current Mirror MOSFET Embedded Pressure Sensor for Healthcare and Biomedical Applications

2013 ◽  
Vol 647 ◽  
pp. 315-320 ◽  
Author(s):  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar
Keyword(s):  
Pressure Sensor ◽  
Biomedical Applications ◽  
Circuit Simulation ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Cmos Technology ◽  
Current Mirror ◽  
Sensing Element ◽  
Pressure Sensing ◽  
Cmos Mems

This paper reports on the design and optimization of current mirror MOSFET embedded pressure sensor. A current mirror circuit with an output current of 1 mA integrated with a pressure sensing n-channel MOSFET has been designed using standard 5 µm CMOS technology. The channel region of the pressure sensing MOSFET forms the flexible diaphragm as well as the strain sensing element. The piezoresistive effect in MOSFET has been exploited for the calculation of strain induced carrier mobility variation. The output transistor of the current mirror forms the active pressure sensing MOSFET which produces a change in its drain current as a result of altered channel mobility under externally applied pressure. COMSOL Multiphysics is utilized for the simulation of pressure sensing structure and Tspice is employed to evaluate the characteristics of the current mirror pressure sensing circuit. Simulation results show that the pressure sensor has a sensitivity of 10.01 mV/MPa. The sensing structure has been optimized through simulation for enhancing the sensor sensitivity to 276.65 mV/MPa. These CMOS-MEMS based pressure sensors integrated with signal processing circuitry on the same chip can be used for healthcare and biomedical applications.

Ultrasensitive, flexible, and low-cost nanoporous piezoresistive composites for tactile pressure sensing

Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2779-2786 ◽  
Author(s):  
Jing Li ◽  
Santiago Orrego ◽  
Junjie Pan ◽  
Peisheng He ◽  
Sung Hoon Kang
Keyword(s):  
Carbon Nanotube ◽  
Polymer Composites ◽  
Low Cost ◽  
Pressure Sensors ◽  
Nanoporous Carbon ◽  
Pressure Sensing ◽  
Etching Method ◽  
Piezoresistive Pressure Sensors

We report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors.

Flexible pressure sensing film based on ultra-sensitive SWCNT/PDMS spheres for monitoring human pulse signals

2015 ◽  
Vol 3 (27) ◽  
pp. 5436-5441 ◽  
Author(s):  
Yan-Long Tai ◽  
Zhen-Guo Yang
Keyword(s):  
Pressure Sensors ◽  
Pressure Sensing ◽  
Prosthetic Limbs ◽  
Electronic Skin ◽  
Essential Components ◽  
Biomedical Diagnostics ◽  
Healthcare Monitoring ◽  
Flexible Pressure Sensors ◽  
Human Healthcare

Flexible pressure sensors are essential components of an electronic skin for future attractive applications ranging from human healthcare monitoring to biomedical diagnostics to robotic skins to prosthetic limbs.

Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines

2013 ◽  
Author(s):  
Juri Bellucci ◽  
Federica Sazzini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Design Tool ◽  
Tip Clearance ◽  
Large Set ◽  
Preliminary Design ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Wide Range ◽  
Pressure Steam

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool. Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries. Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.

Influence of Turbulent Flow Characteristics and Coherent Vortices on the Pressure Recovery of Annular Diffusers: Part A — Experimental Results

2015 ◽  
Author(s):  
Marcus Kuschel ◽  
Bastian Drechsel ◽  
David Kluß ◽  
Joerg R. Seume
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Static Pressure ◽  
Turbulent Transport ◽  
Axial Flow ◽  
Pressure Recovery ◽  
Turbulence Structure ◽  
Reynolds Stresses ◽  
Wide Range ◽  
Operating Points

Exhaust diffusers downstream of turbines are used to transform the kinetic energy of the flow into static pressure. The static pressure at the turbine outlet is thus decreased by the diffuser, which in turn increases the technical work as well as the efficiency of the turbine significantly. Consequently, diffuser designs aim to achieve high pressure recovery at a wide range of operating points. Current diffuser design is based on conservative design charts, developed for laminar, uniform, axial flow. However, several previous investigations have shown that the aerodynamic loading and the pressure recovery of diffusers can be increased significantly if the turbine outflow is taken into consideration. Although it is known that the turbine outflow can reduce boundary layer separations in the diffuser, less information is available regarding the physical mechanisms that are responsible for the stabilization of the diffuser flow. An analysis using the Lumley invariance charts shows that high pressure recovery is only achieved for those operating points in which the near-shroud turbulence structure is axi-symmetric with a major radial turbulent transport component. This turbulent transport originates mainly from the wake and the tip vortices of the upstream rotor. These structures energize the boundary layer and thus suppress separation. A logarithmic function is shown that correlates empirically the pressure recovery vs. the relevant Reynolds stresses. The present results suggest that an improved prediction of diffuser performance requires modeling approaches that account for the anisotropy of turbulence.

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