Sensitive capacitive pressure sensors based on graphene membrane arrays.
Ontology highlight
ABSTRACT:
SUBMITTER: Siskins M
PROVIDER: S-EPMC8433463 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Recently, there has been tremendous interest in flexible pressure sensors to meet the technological demands of modern society. For practical applications, pressure sensors with high sensitivity at small strains and low detection limits are highly desired. In this paper, inspired by the slit sensillum of the scorpion, a flexible pressure sensor is presented which has regular microcrack arrays and its reversed pattern acts as a tunable contact area of the sensing material microstructures. The template with regular crack arrays generated on the inner surface is fabricated using a solvent-induced swelling method, which provides a simple and economical way to obtain the controllable fabrication of crack arrays without any physical damage to materials. At the same time, the working principle of the bio-inspired pressure sensor is attributed to pressure-dependent variations because of the contact area change between the interlocking polydimethylsiloxane films with the negative and positive patterns of the microcrack arrays. The device shows good performance, with a gauge factor of 27.79 kPa-1 (0-2.4 kPa), a short response/recovery time (111/95 ms), a low detectable pressure limit and excellent reproducibility over 3000 cycles. Practical applications, such as the detection of human motion and touch sensing, are then tested in this work, and the results imply that it should have significant potential applications in numerous fields. Note that the reversed pattern of the slit sensillum of the scorpion is explored to enhance the performance of pressure sensors, thus opening a new route for the fabrication of flexible pressure sensors, even wearable electronics, in a cost-effective and scalable manner.
| S-EPMC9067138 | biostudies-literature
Project description:Stretchable capacitive devices are instrumental for new-generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple-step replication. In this study, fabrication of a reliable elongating parallel-plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq-1). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs-based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.
| S-EPMC5827098 | biostudies-literature
Project description:Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.
| S-EPMC5381006 | biostudies-literature
Project description:Membrane-based sensors (MePSs) exhibit remarkable precision and sensitivity in detecting pressure changes. MePSs are commonly used to monitor catalytic reactions in solution, generating gas products crucial for signal amplification in bioassays. They also allow for catalyst quantification by indirectly measuring the pressure generated by the gaseous products. This is particularly interesting for detecting enzymes in biofluids associated with disease onset. To enhance the performance of a MePS, various structural factors influence membrane flexibility and response time, ultimately dictating the device's pressure sensitivity. In this study, we fabricated MePSs using polydimethylsiloxane (PDMS) and investigated how structural modifications affect the Young's modulus (E) and residual stress (σ0) of the membranes. These modifications have a direct impact on the sensors' sensitivity to pressure variations, observed as a function of the volume of the chamber (Σ) or of the mechanical properties of the membrane itself (S). MePSs exhibiting the highest sensitivities were then employed to detect catalyst quantities inducing the dismutation of hydrogen peroxide, producing dioxygen as a gaseous product. As a result, a catalase enzyme was successfully detected using these optimized MePSs, achieving a remarkable sensitivity of (22.7 ± 1.2) µm/nM and a limit of detection (LoD) of 396 pM.
| S-EPMC11013101 | biostudies-literature
Project description:In this work, we demonstrate highly sensitive and scalable Hall sensors fabricated by adopting arrays of monolayer single-crystal chemical vapor deposition (CVD) graphene. The devices are based on graphene Hall bars with a carrier mobility of >12000 cm2 V-1 s-1 and a low residual carrier density of ∼1 × 1011 cm-2, showing Hall sensitivity higher than 5000 V A-1 T-1, which is a value previously only achieved when using exfoliated graphene encapsulated with flakes of hexagonal boron nitride. We also implement a facile and scalable polymeric encapsulation, allowing the performance of graphene Hall bars to be stabilized when measured in an ambient environment. We demonstrate that this capping method can reduce the degradation of electrical transport properties when the graphene devices are kept in air over 10 weeks. State-of-the-art performance of the realized devices, based on scalable synthesis and encapsulation, contributes to the proliferation of graphene-based Hall sensors.
| S-EPMC11348313 | biostudies-literature
Project description:A highly sensitive Gallium Nitride (GaN) diaphragm based micro-scale pressure sensor with an AlGaN/GaN heterostructure field effect transistor (HFET) deflection transducer has been designed and fabricated for high temperature applications. The performance of the pressure sensor was studied over a pressure range of 20 kPa, which resulted in an ultra-high sensitivity of ~0.76%/kPa, with a signal-to-noise ratio as high as 16 dB, when biased optimally in the subthreshold region. A high gauge factor of 260 was determined from strain distribution in the sensor membrane obtained from finite element simulations. A repeatable sensor performance was observed over multiple pressure cycles up to a temperature of 200 °C.
| S-EPMC6187712 | biostudies-literature
Project description:Flexible capacitive pressure sensors with a simple structure and low power consumption are attracting attention, owing to their wide range of applications in wearable electronic devices. However, it is difficult to manufacture pressure sensors with high sensitivity, wide detection range, and low detection limits. We developed a highly sensitive and flexible capacitive pressure sensor based on the porous Ecoflex, which has an aligned airgap structure and can be manufactured by simply using a mold and a micro-needle. The existence of precisely aligned airgap structures significantly improved the sensor sensitivity compared to other dielectric structures without airgaps. The proposed capacitive pressure sensor with an alignment airgap structure supports a wide range of working pressures (20-100 kPa), quick response time (≈100 ms), high operational stability, and low-pressure detection limit (20 Pa). Moreover, we also studied the application of pulse wave monitoring in wearable sensors, exhibiting excellent performance in wearable devices that detect pulse waves before and after exercise. The proposed pressure sensor is applicable in electronic skin and wearable medical assistive devices owing to its excellent functional features.
| S-EPMC9571520 | biostudies-literature
Project description:While the outstanding properties of graphene have attracted a lot of attention, one of the major bottlenecks of its widespread usage is its availability in large volumes. Laser printing graphene on polyimide films is an efficient single-step fabrication process that can remedy this issue. A laser-printed, flexible pressure sensor is developed utilizing the piezoresistive effect of 3D porous graphene. The pressure sensors performance can be easily adjusted via the geometrical parameters. They have a sensitivity in the range of 1.23 × 10-3 kPa and feature a high resolution with a detection limit of 10 Pa in combination with an extremely wide dynamic range of at least 20 MPa. They also provide excellent long-term stability of at least 15 000 cycles. The biocompatibility of laser-induced graphene is also evaluated by cytotoxicity assays and fluorescent staining, which show an insignificant drop in viability. Polymethyl methacrylate coating is particularly useful for underwater applications, protecting the sensors from biofouling and shunt currents, and enable operation at a depth of 2 km in highly saline Red Sea water. Due to its features, the sensors are a prime choice for multiple healthcare applications; for example, they are used for heart rate monitoring, plantar pressure measurements, and tactile sensing.
| S-EPMC7117846 | biostudies-literature
Project description:Flexible, wearable pressure sensors offer numerous benefits, including superior sensing capabilities, a lightweight and compact design, and exceptional conformal properties, making them highly sought after in various applications including medical monitoring, human-computer interactions, and electronic skins. Because of their excellent characteristics, such as simple fabrication, low power consumption, and short response time, capacitive pressure sensors have received widespread attention. As a flexible polymer material, polydimethylsiloxane (PDMS) is widely used in the preparation of dielectric layers for capacitive pressure sensors. The Young's modulus of the flexible polymer can be effectively decreased through the synergistic application of sacrificial template and laser ablation techniques, thereby improving the functionality of capacitive pressure sensors. In this study, a novel sensor was introduced. Its dielectric layer was developed through a series of processes, including the use of a sacrificial template method using NaCl microparticles and subsequent CO2 laser ablation. This porous PDMS dielectric layer, featuring an array of holes, was then sandwiched between two flexible electrodes to create a capacitive pressure sensor. The sensor demonstrates a sensitivity of 0.694 kPa-1 within the pressure range of 0-1 kPa and can effectively detect pressures ranging from 3 Pa to 200 kPa. The sensor demonstrates stability for up to 500 cycles, with a rapid response time of 96 ms and a recovery time of 118 ms, coupled with a low hysteresis of 6.8%. Furthermore, our testing indicates that the sensor possesses limitless potential for use in detecting human physiological activities and delivering signals.
| S-EPMC11359779 | biostudies-literature
Project description:The two dimensional, honeycomb structured, single carbon layered graphene has extensively been used in the field of sensor detection due to its unique physicochemical properties. These properties such as excellent electrical conductivity, high electron mobility, tunable optical properties, room temperature quantum Hall effect, large surface to volume ratio, high mechanical strength, and ease of functionalization, make it an ideal nanomaterial for sensor development. This has enabled the fabrication of a large variety of highly sensitive sensors which include colorimetric, electrochemical, potentiometric, fluorescence, etc. based sensors. These sensors in conjugation with graphene or its derivatives such as graphene quantum dots, graphene oxide, reduced graphene oxide, etc. show highly desirable properties such as high sensitivity (detecting minute amounts of target analyte), specificity (no cross reactivity while detecting the target analyte), rapid results, low cost, extended storage shelf life and robustness (stability), and easy-to-use capabilities (user-friendly). This book chapter gives a detailed overview of all the advances made in the development and fabrication of novel graphene based sensors and their application in point of care (PoC) detection of various diseases as well as health monitoring devices. The different sensors, their methods of fabrication, their sensitivity and the analytes and biomolecules used have been discussed in detail and compared.
| S-EPMC7518956 | biostudies-literature