Sensitive Pressure Sensor Research Articles

Characterization of Hydroacoustic Optical Fibre Bragg Grating Pressure Sensor Using Different Materials

The Exploration of the ocean with sound waves submarines, object tracking, bed deposits, and ocean communications requires a high sensitive hydroacoustic pressure sensor. Design of highly sensitive hydroacoustic challenges and needs of the present scenario. Proposed work involves the design and development of fiber Bragg grating hydroacoustic pressure sensors for underwater communication. Here side hole package is designed and analyzed in Ansys Multiphysics. Three different coating material is such as the layer of titanium, polyamide, and gold is coated on core fiber of fiber Bragg grating sensor and specific mechanical properties of the layer have been assigned. Centre wavelength and sensitivity of the designed FBG sensor is investigated by applying pressure in the range of 100 MPa to 900 MPa. From the results it is also observed that even for small pressure value sensitivity obtained was considerably high, thus satisfying the requirement of hydroacoustic pressure sensor to detect the low-pressure acoustic signals. The high sensitivity of 4590 nm/RIU obtained for the coating material of polyamide. The result obtained has shown feasibility for the fabrication of FBG for different applications such as underwater acoustic, ocean communication.

Highly Sensitive and Flexible Capacitive Pressure Sensor Enhanced by Weaving of Pyramidal Concavities Staggered in Honeycomb Matrix

Large scale production of highly sensitive and flexible pressure sensor has aroused widely interest for their high potential use in real-wearable electronics and e-textiles. In this work, a flexible and wearable capacitive pressure sensor has been fabricated based on the unique honeycomb weave architecture, conferring the sensor with an extreme synchronization between output capacitance and input pressure, as well as the high sensitivity of 0.045 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> under 10 kPa, large workable pressure range of 40 kPa, good durability and stability over 1000 cycles, fast response time of 135 ms and comparable stability under diverse pressures. The sensor can be used for various pressure detections such as finger pressing, tape loading and handshaking. Moreover, the self-made sensor has good ability in monitoring spatial distribution, showing its promising application in flexible and wearable devices.

Highly Sensitive Interlocked Piezoresistive Sensors Based on Ultrathin Ordered Nanocone Array Films and Their Sensitivity Simulation.

Achieving a continuously adjustable micro-nanostructure of sensing materials is crucial and still a challenge for the flexible pressure sensor. We proposed a new method to prepare ultrathin ordered nanocone array films by designing tunable tapered anodized aluminum oxide templates and to prepare highly sensitive flexible pressure sensors by the interlocking nanocone arrays. Meanwhile, the theoretical prediction model of the sensitivity of interlocked nanocone arrays is proposed, and its result shows that the resistance change rate is positively correlated with the height of interlocked nanocone arrays and the contact area between interlocked nanocones. According to the finite element simulation and experimental results, the interlocked ordered nanocone array pressure sensor exhibits a high sensitivity of 268.36 kPa-1 in the pressure range of 0-200 Pa, an ultralow detection limit of 0.98 Pa, a fast response/recovery time of 48/56 ms, a low hysteresis of ±3.156%, stability under 5000 cycles of loading, and continuity and repeatability under different loads and loading speeds. Furthermore, the pressure sensor can accurately monitor weak wind velocities, wrist torsion and bending movement, and book opening and closing angles. The sensor has broad application prospects in wearable medical monitoring, electronic skin, and human-computer interaction.

Facile Fabrication of MoSe2 on Paper as an Electromechanical Piezoresistive Pressure–Strain Sensor

Over the last decade, the rapid development in health care industry and security has driven innovations in the field of wearable electronics and smart sensors. This report demonstrates the fabrication of molybdenum diselenide (MoSe2) by a facile, low-cost and scalable hydrothermal synthesis method followed by a vacuum filter deposition on cellulose paper. The fabricated device is utilized as a pressure and strain sensor. The fabricated device is passivated using polydimethylsiloxane (PDMS), and also, PDMS film enhances the flexibility of the device. The calculated sensitivity of pressure sensor is ~0.3 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , which is comparable and relatively better than the pressure sensor fabricated using sophisticated techniques. Furthermore, the device exhibited significant of merit for strain sensing with a gauge factor of ~6.84. The fabricated device showed excellent resilience in 500 cycle bending tests, which promises the robustness of the device. As an application, the fabricated sensor is used to develop a wireless keyboard by integrating the sensor on fingertips of an individual and a real-time human motion monitoring application in which the data are transmitted wirelessly to a smartphone with a dedicated android application. The successful fabrication of MoSe2/paper-based cost-effective, flexible, and biodegradable pressure-strain sensor shows tremendous applications in future intelligent user interface systems, human security, and personal health care monitoring.

Sensitive capacitive pressure sensors based on graphene membrane arrays

The high flexibility, impermeability and strength of graphene membranes are key properties that can enable the next generation of nanomechanical sensors. However, for capacitive pressure sensors, the sensitivity offered by a single suspended graphene membrane is too small to compete with commercial sensors. Here, we realize highly sensitive capacitive pressure sensors consisting of arrays of nearly ten thousand small, freestanding double-layer graphene membranes. We fabricate large arrays of small-diameter membranes using a procedure that maintains the superior material and mechanical properties of graphene, even after high-temperature annealing. These sensors are readout using a low-cost battery-powered circuit board, with a responsivity of up to 47.8 aF Pa−1 mm−2, thereby outperforming the commercial sensors.

Highly sensitive pressure sensor with broad linearity via constructing a hollow structure in polyaniline/polydimethylsiloxane composite

Flexible pressure sensors are increasingly required for their widely practical applications in health monitoring, humanoid robotics and wearable electronics. Although the geometric microstructure design or active material selection for sensor has been manipulated by many researchers, achieving the desired pressure sensor possessing high sensitivity over a broad linear detection range is still challenging. Herein, a flexible and wearable pressure sensor is demonstrated based on the polyaniline/polydimethylsiloxane (PANI/PDMS) composite with hollow structure and micro-protrude surface structure. The sensitivity and linearity of the as-fabricated sensor could be greatly enhanced through the construction of hollow structure and micro-protrude surface structure, reaching a sensitivity of 0.641 kPa−1 over a broad linear range (0.05–60 kPa), and the sensor also exhibits stable cycling performances (6000 cycles), fast response time (200 ms) and recovery time (150 ms). Importantly, the sensing mechanism of this sensor is theoretically studied, a sensing model based on tunneling effect and contact mechanic is proposed and its validity is experimentally verified. Finally, the pressure sensor demonstrates practical applications in object operations, answering mouse click and feet movements, thereby providing a significant guidance for constructing advanced electronic devices.

Highly Sensitive Pressure and Strain Sensors Based on Stretchable and Recoverable Ion-Conductive Physically Cross-Linked Double-Network Hydrogels.

Ion-conductive hydrogel sensors have attracted great research interests for applications in wearable devices, electronic skins, and implantable sensors, but most such sensors are fragile, with low conductivity and sensitivity. This study reports on novel ion-conductive double network hydrogels with a cross-linked helical structure, hydrophobic association, and metal-ion coordination. The helical κ-carrageenan first network and the second network cross-linked by Pluronic F127 diacrylate micelles and tridentate Fe3+-COO- coordination work synergistically to show the tensile strength of 2.7 MPa, fracture strain of 1400%, and tensile toughness of 9.82 MJ m-3 and fatigue resistance against cyclic loadings with high strains. The hydrogels show an ion conductivity of 1.15 S m-1, a strain sensitivity of up to 2.8, and a pressure sensitivity of 0.33 kPa-1. Sensor arrays fabricated from the conductive hydrogels provide an in-plane detection of pressures less than 200 Pa. Such hydrogel sensors have potential applications to electron skins and implantable sensors.

Load Share Mapping for Traditional PEEK vs Novel Hybrid PEEK With Expandable Porous Mesh Intervertebral Devices.

A successful intervertebral fusion requires biomechanical stability created by the structural support of the interbody device and loading of the bone graft material to accelerate mechanotransduction and bone remodeling. The objective of this study was to generate a quantitative map of the contact area and stress profile for 2 implant designs; a rigid monolithic polyetheretherketone (PEEK) lateral cage (MPLC), and a unique hybrid interbody design, which includes PEEK terminal supports surrounding an expandable porous mesh (P+EPM) that serves to contain bone graft. The construct for each test consisted of a device sandwiched between 2 flat or shaped Grade 15 foam blocks. Pressure sensitive film and thin film sensors were placed between the device and each of the foam blocks. A series of each implant type was compressed at a rate 0.1 mm/second for 2 loads (1100 N and 2000 N) with and without bone graft. Device and bone graft contact area were analyzed for each test condition and corresponding load profiles were quantified and mapped. P+EPM demonstrated 34% greater graft volume than MPLC resulting in a 28% larger area for bone exchange when filled. The load profiles for all applied loading paradigms for P+EPM demonstrated significant direct loading on the bone graft contained within the mesh, resulting in at least 170% greater loaded area than MPLC. Furthermore, the P+EPM demonstrated load sharing with the terminal PEEK supports. MPLC for all loading conditions demonstrated negligible bone graft loading. P+EPM allows for an optimized contact area for bone exchange and graft incorporation. The load profiles confirmed that the filled mesh does not stress shield terminal PEEK supports and will load share. The expandable, compliant, porous mesh provides a greater multiplanar area for bone exchange and allows for direct contact with the viscoelastic vertebral endplates, improving the endplate and graft interface mechanics.

Flexible, Highly Sensitive, and Ultrafast Responsive Pressure Sensor with Stochastic Microstructures for Human Health Monitoring

Flexible and wearable sensors are now becoming the favorite of the new information age for their great prospects, especially in human health monitoring, and which are mainly aimed at improving the comprehensive sensing performance. However, the equilibrium between sensitivity and response time of the sensor has not been well balanced. Herein, a simple and low‐cost strategy to fabricate flexible pressure sensors based on thermoplastic polyurethane (TPU) substrate with unique surface stochastic morphology replicated from the abrasive paper, which is inspired by skin epidermis, is presented. The integrated TPU flexible pressure sensor exhibits a high sensitivity of −2.24 kPa−1 in a linear pressure regime of 0–200 Pa, and the effective working range of this sensor is close to 2 kPa, ultrafast response time and relaxation time of 10 ms, low detection limits of 0.72 Pa, and excellent cycling stability over 3000 cycles. The fabricated sensors demonstrate outstanding sensing capabilities in monitoring human physiological signals, such as subtle pulse, wrist movement, and speech recognition, making promising potential in practical human health monitoring applications.

Improved traceable measurement of the reflected step pressure in shock tube with the compensation of shock wave attenuation

Shock tube is an exceptional valuable facility that can produce approximately ideal step pressure from the reflected shock wave for the dynamic characterization of pressure sensors in aerospace industry. However, the traceable measurement accuracy of the reflected step pressure (RSP) is limited by the inevitable attenuation of the incident shock wave (ISW), leading to the dynamic characterization results with large error. This paper proposes an improved method for achieving high-accuracy traceable measurement of RSP in shock tube with the compensation of shock wave attenuation. The traceable measurement model of RSP relates to the ISW velocity is established firstly based on shock tube theory. To compensate the ISW velocity attenuation, a distributed measurement combined with a non-equidistant fractional-order grey (NFOG) method is implemented to establish ISW velocity model in consideration of the nonlinear, small-sample and non-equidistant features of the velocity sequence obtained by multiple sensors. Meantime, an ergodic optimization method based on a similarity index is adopted to estimate the optimal fractional-order in NFOG. With ISW velocity model, the velocity at the end-wall of shock tube is predicted and then more reliable RSP result is achieved with the traceable measurement model. Four experiments under different shock wave conditions are carried out to verify the proposed method. Results show that NFOG is able to establish the velocity model effectively, and the modeling error is less than that of the non-equidistant grey model and least square fitting methods. Furthermore, the traceable measurement accuracy of RSP by the proposed method is improved significantly than existing methods according to the investigation of pressure sensor sensitivity in both dynamic and static conditions.

Highly Sensitive P(VDF-TrFE)/BTO Nanofiber-Based Pressure Sensor with Dense Stress Concentration Microstructures

Flexible pressure sensors demonstrate promising potential in human–machine interfaces, wearable devices, and implantable electronics. In this study, a highly sensitive pressure sensor was developed...

Highly sensitive and flexible pressure sensor based on two-dimensional MoSe2 nanosheets for online wrist pulse monitoring

The advancement of portable and flexible electronics that is integrated with multiple sensing functions has increasingly drawn considerable interest. The fabricated sensors would have the ability to sense multiple deformations like pressing, twisting and trivial vibrations such as pulses of wrist vibrations to mimic human skin. Presently, we implemented an easy, cost-effective and optimized fabrication technique for production of pressure sensors based on MoSe2 nanosheets coated on cellulose paper. The present sensor exhibits an incorporation of large pressure sensitivity of 18.42 kPa−1 in pressure range 0.001–0.5 kPa, 7.28 kPa−1 in pressure range 1–35 kPa and 2.63 kPa−1 in pressure range 40–100 kPa, working in broad pressure range (from 0.001 to 100 kPa) and long-term stability up to 200 deformation cycles at 2 kPa. The sensor showed excellent response towards the detection of vibrations of machines including cellular phone, compressor, etc. Besides, the sensor shows excellent environmental stability and exhibits immune piezo-resistive response to temperature variation.

Simple fabrication of highly sensitive capacitive pressure sensors using a porous dielectric layer with cone-shaped patterns

This study aims to improve the sensitivity of sensors using porous structures and cone-shaped patterns in the composition of a capacitive pressure sensor. A simple and rapid fabrication method for the production of porous structures and cone-shaped patterns using microwave irradiation of emulsions containing polydimethylsiloxane (PDMS) and a sacrificial solvent is introduced in this study. Through this method, a porous PDMS dielectric layer could be simply fabricated within a few minutes. The sensitivity was greatly improved by both enhancing deformability and increasing the dielectric constant under the external pressure. The effect of pattern distance was investigated, and the sensor with the pattern distance of 600 μm showed a remarkably high sensitivity of approximately 5 kPa−1. Moreover, the effect of aspect ratio and sharpness of the patterns were also studied through a finite element analysis. Finally, we demonstrated the performance of the sensor using a sensor array and finger attached sensors, and they showed sufficient performance for use in wearable devices applicable to artificial skin, surgical robots, and pressure monitoring systems, among others.

Pressure Sensors: Cross‐Linked Gold Nanoparticle Composite Membranes as Highly Sensitive Pressure Sensors (Adv. Funct. Mater. 40/2020)

Pressure Sensors: Cross‐Linked Gold Nanoparticle Composite Membranes as Highly Sensitive Pressure Sensors (Adv. Funct. Mater. 40/2020)

Highly sensitive fiber optic pressure sensors for wind turbine applications

Highly sensitive fiber optic pressure sensors for wind turbine applications

Alcohol-based highly conductive polymer for conformal nanocoatings on hydrophobic surfaces toward a highly sensitive and stable pressure sensor

Conformal and ultrathin coating of highly conductive PEDOT:PSS on hydrophobic uneven surfaces is essential for resistive-based pressure sensor applications. For this purpose, a water-based poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) solution was successfully exchanged to an organic solvent-based PEDOT:PSS solution without any aggregation or reduction in conductivity using the ultrafiltration method. Among various solvents, the ethanol (EtOH) solvent-exchanged PEDOT:PSS solution exhibited a contact angle of 34.67°, which is much lower than the value of 96.94° for the water-based PEDOT:PSS solution. The optimized EtOH-based PEDOT:PSS solution exhibited conformal and uniform coating, with ultrathin nanocoated films obtained on a hydrophobic pyramid polydimethylsiloxane (PDMS) surface. The fabricated pressure sensor showed high performances, such as high sensitivity (−21 kPa−1 in the low pressure regime up to 100 Pa), mechanical stability (over 10,000 cycles without any failure or cracks) and a fast response time (90 ms). Finally, the proposed pressure sensor was successfully demonstrated as a human blood pulse rate sensor and a spatial pressure sensor array for practical applications. The solvent exchange process using ultrafiltration for these applications can be utilized as a universal technique for improving the coating property (wettability) of conducting polymers as well as various other materials.

Robust Flexible Pressure Sensors Made from Conductive Micropyramids for Manipulation Tasks.

Flexible pressure sensors that can robustly mimic the function of slow-adapting type I (SA-I) mechanoreceptors are essential for realizing human-like object manipulation in artificial intelligent (AI) robots or amputees. Here, we report a straightforward approach to highly sensitive and robust flexible pressure sensors with fast response time and low operating voltage based on conductive micropyramids made of polydimethylsiloxane/carbon nanotube composites. Both numerical simulations and experimental studies show that the pressure-sensing properties of the devices can be systematically tuned by the spatial arrangement of micropyramids. In particular, by tailoring the ratio between the spacing and the pyramidal base length, the optimal pressure sensors can be achieved with a combination of high sensitivity in both low-pressure (<10 kPa) and medium-pressure (10-100 kPa) regimes, rapid response, high mechanical robustness, low operating voltage, and low power consumption, along with linear response and low hysteresis in the medium-pressure regimes. The optimized pressure sensor is further used for constructing a wearable pressure-sensing system that can convert the amplitude of pressure to wirelessly transmittable frequency signals (spikes) with nearly linear response, closely mimicking SA-I mechanoreceptors. Furthermore, we demonstrate that the high uniformity and scalability of the pressure sensors enable large-area pressure-sensing arrays for spatially resolved pressure mapping.

Highly sensitive FBG pressure sensor based on square diaphragm

A highly sensitive fiber Bragg grating (FBG) based square diaphragm pressure sensor has been designed and verified both in theory and experiment. The square diaphragm deflects due to the pressure difference generated at both sides of the square, and causes the compression along the axis of the pre-stretched FBG. The experimental results indicate that the pressure sensitivity of the proposed sensor reaches 3.402 pm/kPa in the range of 0–200 kPa with a higher coefficient of determination of 0.9985. Meanwhile, the sensor is found to present low hysteresis, good repeatability and resolution. Relative error recorded at 3.13 % represents that the effect of the temperature compensation is remarkable. Furthermore, the designed pressure sensor is simple, cost-effective and suitable for low pressure measurement.

Three-Dimensional MOF-Assisted Self-Polarized Ferroelectret: An Effective Autopowered Remote Healthcare Monitoring Approach.

In recent years, flexible and sensitive pressure sensors are of extensive interest in healthcare monitoring, artificial intelligence, and national security. In this context, we report the synthetic procedure of a three-dimensional (3D) metal-organic framework (MOF) comprising cadmium (Cd) metals as nodes and isoniazid (INH) moieties as organic linkers (CdI2-INH═CMe2) for designing self-polarized ferroelectret-based highly mechano-sensitive skin sensors. The as-synthesized MOF preferentially nucleates the stable piezoelectric β-phase in poly(vinylidene fluoride) (PVDF) and also gives rise to a porous ferroelectret composite film. Benefiting from the porous structure of 3D MOFs, composite ferroelectret film-based ultrasensitive pressure sensor (mechano-sensitivity of 8.52 V/kPa within 1 kPa pressure range) as well as high-throughput ( power density of 32 μW/cm2) mechanical energy harvester (MEH) has been designed. Simulation-based finite element method (FEM) analysis indicates that the geometrical stress confinement effect within the interpore region of the ferroelectret structure synergistically influences the mechano-electrical property of the MEH. In addition, 143 pC/N (∼4.5 times higher than commercial piezoelectric PVDF films) piezoelectric charge coefficient (d33) magnitude and superior response time (tr ∼ 8 ms) of this composite ferroelectret film enable the detection of different physiological signals such as coughing, pronunciation, and gulping behavior, making it a promising candidate for early intervention of healthcare, which may play a significant role in accurate alert of influenza and chronic obstructive pulmonary disease (COPD)-related symptoms. In addition, MEH enables the tracking of the subtle pressure change in the wrist pulse, indicating its usefulness in effective mechano-sensitivity. Since the cardiovascular signal is one of the vital parameters that can determine the on-going physiological conditions, the wireless transmission of the detected wrist pulse signal has been demonstrated. All of these features coupled with wireless data transmission indicate the promising application of MOF-assisted composite ferroelectret films in noninvasive real-time remote healthcare monitoring.

Cross‐Linked Gold Nanoparticle Composite Membranes as Highly Sensitive Pressure Sensors

AbstractIn this article, highly sensitive differential pressure sensors based on free‐standing membranes of cross‐linked gold nanoparticles are demonstrated. The nanoparticle membranes are employed as both diaphragms and resistive transducers. The elasticity and the pronounced resistive strain sensitivity of these nanometer‐thin composites enable the fabrication of sensors achieving high sensitivities exceeding 10−3 mbar−1 while maintaining an overall small membrane area. Furthermore, by combining micro‐bulge tests with atomic force microscopy and in situ resistance measurements the membranes’ electromechanical responses are studied through precise observation of the concomitant changes of the membranes’ topography. The study demonstrates the high potential of free‐standing nanoparticle composites for the fabrication of highly sensitive force and pressure sensors and introduces a unique and powerful method for the electromechanical investigation of these materials.