Pressure Sensor For Applications Research Articles

In situ fabrication of porous polymer films embedded with perovskite nanocrystals for flexible superhydrophobic piezoresistive sensors

The application of pressure sensors based on perovskite in high-humidity environments is limited by the effect of water on their stability. Endowing sensors with superhydrophobicity is an effective strategy to overcome the issue. In this work, MAPbBr3/Polyvinylidene Fluoride-TFSI composite was prepared by a one-step in-situ strategy to form a flexible superhydrophobic pressure sensor, which exhibited a contact angle of 150.25°. The obtained sensor exhibited a sensitivity of 0.916 in 1 kPa, a detection limit of 0.2 Pa, a precision of 0.1 Pa, and a response/recovery of ∼100 ms, along with good thermal stability. Through density functional theory calculations, it is revealed that the formation of the porosity is attributed to the interaction between the polymer and EMIM TFSI, which further leads to superhydrophobicity. And, the perovskite structure is easy to change under pressure, affecting the carrier transport and electrical signals output, which explains the sensing mechanism. In addition, the sensor performed well in monitoring facial expression, pulse, respiration, finger bending, and wind speed ranging from 1 m/s to 6 m/s. With both the Linear Regression and the Random Forest algorithm, the sensor can monitor the wind speed with an R2 greater than 0.977 in 60 tests.

Linear Capacitive Pressure Sensor with Gradient Architecture through Laser Ablation on MWCNT/Ecoflex Film.

The practical application of flexible pressure sensors, including electronic skins, wearable devices, human-machine interaction, etc., has attracted widespread attention. However, the linear response range of pressure sensors remains an issue. Ecoflex, as a silicone rubber, is a common material for flexible pressure sensors. Herein, we have innovatively designed and fabricated a pressure sensor with a gradient micro-cone architecture generated by CO2 laser ablation of MWCNT/Ecoflex dielectric layer film. In cooperation with the gradient micro-cone architecture and a dielectric layer of MWCNT/Ecoflex with a variable high dielectric constant under pressure, the pressure sensor exhibits linearity (R2 = 0.990) within the pressure range of 0-60 kPa, boasting a sensitivity of 0.75 kPa-1. Secondly, the sensor exhibits a rapid response time of 95 ms, a recovery time of 129 ms, hysteresis of 6.6%, and stability over 500 cycles. Moreover, the sensor effectively exhibited comprehensive detection of physiological signals, airflow detection, and Morse code communication, thereby demonstrating the potential for various applications.

Design and application of pressure sensor based on fiber Bragg grating

Design and application of pressure sensor based on fiber Bragg grating

Polyethyleneimine Controlled Impregnation of Silver Nanowires on Electrospun Ceramic Sponges

AbstractElectrospun sponges with electrical conductivity are promising materials for electrodes with applications in pressure sensors, flexible wearable sensors, and supercapacitors. However, electrospun sponges display poor electric conductivity, which can be increased by the addition of silver nanowire (AgNW). The resulting electric conductivity may depend strongly on the distribution of the AgNW in and on the sponges. A straightforward assembly method for an elastic conductive sponge, composed of 3D structures and metal nanowires, using a synergistic strategy which involves modified impregnation and deposition processes assisted by polyethyleneimine (PEI) impregnation, is presented. The resulting changes in the material properties are also explored, and it is under specific conditions, that percolation, leading to significantly enhanced electrical conductivity in the sponges, is achieved.

Innovative Silicon-Ceramic (SiCer) Technology for High-Strength Pressure Sensor Applications Using Different Manufacturing Methods

A variety of manufacturing methods can be used to assemble silicon-based piezoresistive pressure sensors, such as anodic bonding or silicon direct bonding. To achieve highstrength pressure sensors, a high quality interface connection is required. The combination of silicon and ceramic creates a new innovative composite system known as Silicon-on-Ceramics, short SiCer. By using a special developed bondable Low Temperature Co-fired Ceramic tape, which corresponds to the thermal expansion coefficient of Si, the combination of both materials is possible through a sintering process. Advantages of the SiCer technology are high temperature stability, manufacturing at wafer-level and a high bond strength at the interface. Different manufactured SiCer-based pressure sensors were fabricated, electrically and mechanically characterized and compared with anodic bonded and silicon direct bonded pressure sensors.

Effect of facet gap on heliostat wind loading

Multi-facet heliostats are more versatile and advantageous in design compared to single facet heliostats, while generating new design challenges. Multi-facet designs can reduce manufacturing costs, allow for decentralisation of power supply, and bring the option of face down stow. Addition of a gap between two facets, changes the flow structure around the heliostat. The effect of gap between two heliostat facets is therefore investigated on wind loads through experimental investigation in a large wind tunnel. A heliostat model was placed in a simulated atmospheric boundary layer at The University of Adelaide wind tunnel. The investigation covered gap ratios between two panels (gap spacing/facet width) from 0 to 2, and panel aspect ratios (facet width/chord length) of 0.35 to 0.65, forming a complete heliostat aspect ratio of 0.7 to 1.3 with no gap. Wind load coefficients were determined using load cell measurements at the base, and application of differential pressure sensors on the surface, of the heliostat model. Findings indicate the presence of a gap, in general, increases the wind load on the heliostat, with facet aspect ratio exacerbating the results. The maximum load cases shift further into the operating range of heliostats where a change in centre of pressure, due to a change in gap ratio, shifts maximum coefficients from an elevation angle of 30° to 45° for lift force and hinge moment, and 90° to 75° for azimuthal moment. Increasing loads on elevation and azimuth drives potentially increases tracking deviations and beam misalignment, reducing concentrated solar power plant performance.

Temperature compensation for piezoresistive pressure sensor based on deep learning on graphs

With the escalating demand for precision in piezoresistive pressure sensors to cater to a wide spectrum of applications, a significant challenge emerges due to the material properties of these sensors, which induce a substantial temperature coefficient. This limitation restricts the operational temperature range and is further exacerbated by ambient temperature variations, resulting in pronounced nonlinearity in sensor responses. To address these challenges, A new method using Graph Neural Networks (GNNs) is introduced to address nonlinearity and temperature drift in piezoresistive pressure sensors. GNNs improve the sensors’ accuracy and reliability across different temperatures, expanding their applicability. Test results show a notable accuracy enhancement, with a maximum full-scale error below 0.05% and even lower in specific ranges (under 0.04%). This precision makes the method ideal for industrial pressure sensor applications and production, offering significant benefits.

Additively Manufactured Stress-strain Dependant Frequency Reconfigurable Antenna for Pressure Sensor Applications

A novel additive-manufactured antenna for stretchable sensor application is designed, simulated and measured. The fully transparent antenna has air as a substrate and a conductive aluminium metal sheet as a patch. The layers are defined with thin Thermo Poly Urethane (TPU) material, as its flexible/stretchable property doesn't disturb the actual property of air. The air substrate is locked within the flexible TPU with a thickness of 200 microns, and the conducting patch is also dimensioned with the 3D printing method. The stretchable antenna is fabricated with 3D printing technology, considered a dielectric medium, and the conducting medium is a conducting aluminium sheet. Re-configurability is achieved with the pressure level applied over the air–substrate antenna. Hence, the minimal change in shape changes the dielectric constant, thus changing the antenna parameter and radiation pattern. The antenna achieves improved size and performance with a gain of 7.2 dB, a directivity of 7.574 dB, a radiation efficiency of 95.67 %, and a 12:509 front-to-back ratio. The fabricated antenna is tested for its resonant characteristics and radiation properties. This reconfigurable antenna can be used for various applications, including Wireless Local Area Network (WLAN) communication.

Regulable high-contrast mechanofluorochromic enhancement behaviour based on substituent effects.

Herein, a facile strategy was established to build mechanoresponsive luminogens with high sensitivity to substituents and positional effects. Even in slightly different structures, distinct optical phenomena, including fluorescence efficiency and mechano-responsive properties, were clearly present. Outstanding mechanical-induced emission enhancement (5-100 times) properties and reversibility makes for promising applications in pressure sensors and OLEDs.

Numerical Simulation of Highly Sensitive Ga2O3 Pressure Sensor

This article presents beta‐gallium oxide (β‐Ga2O3) micro electro mechanical systems (MEMS) strain/pressure sensors as a way to enhance sensitivity. The model consists of four piezoresistive strain gauges connected in a Wheatstone bridge configuration. The MEMS model is simulated from 0 Pa to 50 kPa, resulting in an output signal range of −3–16 mV and a responsivity of 0.38 mV kPa−1. The simulation also shows that as temperature increases, the resistance of the piezoresistive material in the MEMS decreases, leading to changes in the output signals. The reliable device effectively utilizes the full Wheatstone bridge configuration to compensate for temperature‐related influences. These early results suggest that Ga2O3‐based MEMS devices have great potential for use in high‐temperature pressure sensor applications in the future.

Lightweight, flexible, and conductive PEDOT:PSS coated polyimide nanofibrous aerogels for piezoresistive pressure sensor application

Conductive PEDOT:PSS-coated polyimide nanofibrous aerogels as piezoresistive pressure sensors.

Eco-designed recycled newspaper for energy harvesting and pressure sensor applications

This study focuses on developing multifunctional electronic paper (e-paper) using a low-cost recycling method to minimize the usage of critical raw materials. The e-paper is designed for various smart applications, such as mechano-responsive energy harvesters and pressure sensors. The emphasis is on adopting an eco-friendly approach by utilizing cellulose extracted from used newspapers, which would otherwise have been discarded. The formulated e-paper contains 100 % recycled cellulose fibers, unlike the more commonly used recycled paper, which contains around 70 % of recycled cellulose and 30 % of new pulp. The recycled paper (RP) was functionalized using polyaniline (PANi), resulting in a conductive e-paper, capable of generating electric current through a charge transfer mechanism at the PANi-Cellulose/electrode interface layer. The resulting devices demonstrate satisfactory energy production, with output voltage ranging from 16.8 to 20.25 V, output current ranging from 0.9 µA to 1.75 µA, and power density ranging from 0.18 to 0.35 Wm−2. The mechanical impulses generated by the device can successfully light up several LEDs in series. Additionally, the e-paper was investigated as a flexible, paper-based pressure sensor. The fabricated device exhibited excellent sensitivity, fast response time, and a wide detection range from 25 Pa to 12.25 kPa. The sensitivity of the pressure sensors achieved 4.21 kPa−1 within a low range of 0–1 kPa and approximately 0.008 kPa-1for a broader pressure range (2 – 12.25 kPa). Additionally, the durability of the pressure sensing devices has undergone rigorous testing, surpassing 2000 cyclic tests.

A flexible graphene pressure sensor with high sensitivity based on sewn multi-layer anti-slip cloth

High sensitivity and scalable fabrication are crucial for the application of flexible pressure sensors. However, to improve the sensitivity of the pressure sensor, the fabrication inevitably becomes more complex. Herein, a flexible graphene pressure sensor with high sensitivity was fabricated by soaking the sewn multi-layer anti-slip cloth in graphene inks. The fabrication was greatly simplified by the use of commercially available anti-slip cloth and graphene inks without additional chemical reducing agent. Based on theoretical analysis and experimental test, the optimal structure of sensitive layers was found by changing the number of layers and particles. With the help of hemispherical particles on anti-slip cloth and structural design, the pressure sensor shows high reliability, outstanding sensitivity (up to 0.40 kPa−1) and large working range (0–20 kPa). The pressure sensor is further demonstrated to be capable of detecting human activities such as voice, grip, wrist pulse, breathing, etc.

Inverted Molding with Porous Skeleton Nickel Foam for Preparing Flexible Multi-Wall Carbon Nanotubes Pressure Sensors

The application of traditional pressure sensors in health monitoring is limited by their initial rigidity. Flexible pressure sensors have thus received extensive attention owing to their excellent device flexibility. In this paper, we demonstrate a method of constructing flexible pressure sensors by inverting porous skeleton nickel foam based on multi-wall carbon nanotubes (MWCNTs) and polydimethylsiloxane (PDMS). MWCNTs and PDMS were mixed to form a composite conductive film, and the mass fraction of MWCNTs was optimized by evaluating the resistance change rate of the composite film. The optimized value of the mass fraction was 5%, which was used to prepare the flexible pressure sensors. The response, hysteresis, and stability of the sensors were further characterized. Pulse signals of humans were detected through flexible sensors, which can be used to evaluate cardiovascular conditions of the human body. These performance characteristics and the application demonstration show that our flexible pressure sensors have good prospects in human health care.

Self-powered flexible battery pressure sensor based on gelatin

The application of pressure sensors with excellent performance in medicine, flexible electronic skin, artificial intelligence, etc. has received much attention. However, most of the current pressure sensors have either the need for an external power supply or the difficulty of accurately measuring the static continuous signal, which greatly limit the development of sensor technology. We report a gelatin-based battery type pressure sensor in which a gelatin composite hydrogel membrane is introduced as the sensing layer in a zinc ion battery, and the zinc battery itself is designed as a pressure sensor. An isolation layer is also added to the solid zinc ion battery to realize the function of converting mechanical pressure signals to electrical signals more accurately. The gelatin battery pressure sensor designed in this paper has the advantages of being self-powered, high sensitivity (37.9 mV/kPa), wide pressure detection range (up to 524 kPa), good stability, short response/recovery time, and high biological applicability. In addition, the battery-type pressure sensor has the ability to detect static signals and maintain good performance under 10,000 s of external mechanical pressure. The design of this battery-based pressure sensor provides a new strategy for the development of self-powered pressure sensors and flexible electronic skin devices.

Integrating Benzoxazine-PDMS 3D Networks with Carbon Nanotubes for flexible Pressure Sensors.

Shapeable and flexible pressure sensors with superior mechanical and electrical properties are of major interest as they can be employed in a wide range of applications. In this regard, elastomer-based composites incorporating carbon nanomaterials in the insulating matrix embody an appealing solution for designing flexible pressure sensors with specific properties. In this study, PDMS chains of different molecular weight were successfully functionalized with benzoxazine moieties in order to thermally cure them without adding a second component, nor a catalyst or an initiator. These precursors were then blended with 1 weight percent of multi-walled carbon nanotubes (CNTs) using an ultrasound probe, which induced a transition from a liquid-like to a gel-like behavior as CNTs generate an interconnected network within the matrix. After curing, the resulting nanocomposites exhibit mechanical and electrical properties making them highly promising materials for pressure-sensing applications.

Knittle Pressure Sensor Based on Graphene/Polyvinylidene Fluoride Nanocomposite Coated on Polyester Fabric.

In this paper, a knittle pressure sensor was designed and fabricated by coating graphene/Polyvinylidene Fluoride nanocomposite on the knitted polyester substrate. The coating was carried out by a dip-coating method in a nanocomposite solution. The microstructure, surface properties and electrical properties of coated layers were investigated. The sensors were tested under the application of different pressures, and the corresponding sensor signals were analyzed in terms of resistance change. It was observed that the change in resistance was 55% kPa-1 with a sensitivity limit of 0.25 kPa. The sensor model was created and simulated using COMSOL Multiphysics software, and the model data were favorably compared with the experimental results. This investigation suggests that graphene-based nanocomposites can be used in knittle pressure sensor applications.

A novel evolutionary method for parameter-free MEMS structural design and its application in piezoresistive pressure sensors

In this paper, a novel simulation-based evolutionary method is presented for designing parameter-free MEMS structures with maximum degrees of freedom. This novel design method enabled semiautomatic structure evolution by weighing the attributes of each segment of the structure and yielded an optimal design after multiple iterations. The proposed method was utilized to optimize the pressure-sensitive diaphragm of a piezoresistive pressure sensor (PPS). Finite element method (FEM) simulations revealed that, in comparison to conventional diaphragms without islands and with square islands, the optimized diaphragm increased the stress by 10% and 16% and reduced the nonlinearity by 57% and 77%, respectively. These improvements demonstrate the value of this method. Characterization of the fabricated PPS revealed a high sensitivity of 8.8 mV V−1 MPa−1 and a low nonlinearity of 0.058% FS at 20 °C, indicating excellent sensor performance.

Sustainable antibacterial collagen composites with silver nanowires for resistive pressure sensor applications

Considering the circular economy and the increasing need of smart materials for the digitalization of society, it is essential that these materials are based on bio-resources. Thus, in order to replace synthetic by natural polymers in multifunctional composites, this work reports on the development of collagen/silver nanowires (Ag NWs) composites for resistive sensor applications. It is demonstrated the physical interactions of hydroxyl groups in collagen with the Ag NWs and that the Ag NWs are well dispersed within the collagen matrix. Further, the addition of Ag NWs to the collagen matrix increases the thermal stability of collagen and the Ag NW content does not affect the triple helix structure of the polymer matrix. The mechanical, electrical and antibacterial properties depend on Ag NW content and the best electric conductivity of 0.0515 S cm−1 is obtained for composites with 6 wt% of Ag NWs. This composite presents suitable resistance variations under pressure and bending allowing the development of sustainable multifunctional sensing composites with antibacterial activity that can be applied in next generation touch sensing electronic devices.

Anti-freezing conductive zwitterionic composite hydrogels for stable multifunctional sensors

Zwitterionic conductive hydrogels have shown potential application in wearable strain and pressure sensors. However, there are still fundamental challenges to achieve zwitterionic hydrogels with excellent mechanical properties, able to keep flexibility at sub-zero temperatures. To overcome these limitations, a zwitterionic conductive hydrogel was fabricated in this work by in-situ polymerization of aniline (ANI) monomer in a copolymer of sulfobetaine methacrylate (SBMA) and acrylic acid (AA) matrix. The obtained hydrogel possesses outstanding anti-freezing performance (without obvious loss of stretchability at −18 °C) and water-retaining properties, due to the introduction of LiCl on the zwitterionic polymer matrix. The synergy of chemical and physical crosslinking between poly (SBMA-co-AA) and polyaniline (PANI) networks enhance the mechanical performance of the zwitterionic hydrogel, that exhibits a fracture tensile strength of 470 kPa, and a fracture strain up to 600 %. Additionally, the integration of PANI confers stable conductivity (2.23 S m−1, maintained at 1.89 S m−1 even at −18 °C), high sensitivity (GF = 1.74), and short response and recovery times (223 ms and 191 ms, respectively). The hydrogel can be applied as a flexible sensor to accurately detect various human motions. This work provides a feasible strategy for developing wearable multifunctional sensors in a wide working temperature range.