scholarly journals Effect of Metal Thickness on the Sensitivity of Crack-Based Sensors

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2872 ◽  
Author(s):  
Eunhan Lee ◽  
Taewi Kim ◽  
Heeseong Suh ◽  
Minho Kim ◽  
Peter Pikhitsa ◽  
...  
Keyword(s):  
American Sign Language ◽  
High Performance ◽  
Metal Layer ◽  
High Sensitivity ◽  
Human Motion ◽  
Motion Detector ◽  
Metal Thickness ◽  
Mechanical Crack ◽  
Pet Film ◽  
The Relationship

Among many attempts to make a decent human motion detector in various engineering fields, a mechanical crack-based sensor that deliberately generates and uses nano-scale cracks on a metal deposited thin film is gaining attention for its high sensitivity. While the metal layer of the sensor must be responsible for its high performance, its effects have not received much academic interest. In this paper, we studied the relationship between the thickness of the metal layer and the characteristics of the sensor by depositing a few nanometers of chromium (Cr) and gold (Au) on the PET film. We found that the sensitivity of the crack sensor improves/increases under the following conditions: (1) when Au is thin and Cr is thick; and (2) when the ratio of Au is lower than that of Cr, which also increases the transmittance of the sensor, along with its sensitivity. As we only need a small amount of Au to achieve high sensitivity of the sensor, we have suggested more efficient and economical fabrication methods. With this crack-based sensor, we were able to successfully detect finger motions and to distinguish various signs of American Sign Language (ASL).

scholarly journals Design of a Sensitive Balloon Sensor for Safe Human–Robot Interaction

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2163
Author(s):  
Dongjin Kim ◽  
Seungyong Han ◽  
Taewi Kim ◽  
Changhwan Kim ◽  
Doohoe Lee ◽  
...  
Keyword(s):  
High Performance ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Robot Interaction ◽  
Large Area ◽  
Tactile Sensors ◽  
Robot Interaction ◽  
Mechanical Crack ◽  
Flexible Strain Sensor ◽  
Contact Sensing

As the safety of a human body is the main priority while interacting with robots, the field of tactile sensors has expanded for acquiring tactile information and ensuring safe human–robot interaction (HRI). Existing lightweight and thin tactile sensors exhibit high performance in detecting their surroundings. However, unexpected collisions caused by malfunctions or sudden external collisions can still cause injuries to rigid robots with thin tactile sensors. In this study, we present a sensitive balloon sensor for contact sensing and alleviating physical collisions over a large area of rigid robots. The balloon sensor is a pressure sensor composed of an inflatable body of low-density polyethylene (LDPE), and a highly sensitive and flexible strain sensor laminated onto it. The mechanical crack-based strain sensor with high sensitivity enables the detection of extremely small changes in the strain of the balloon. Adjusting the geometric parameters of the balloon allows for a large and easily customizable sensing area. The weight of the balloon sensor was approximately 2 g. The sensor is employed with a servo motor and detects a finger or a sheet of rolled paper gently touching it, without being damaged.

scholarly journals Flexible Ecoflex®/Graphene Nanoplatelet Foams for Highly Sensitive Low-Pressure Sensors

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4406
Author(s):  
Marco Fortunato ◽  
Irene Bellagamba ◽  
Alessio Tamburrano ◽  
Maria Sabrina Sarto
Keyword(s):  
High Performance ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Cost Effective ◽  
Low Pressure ◽  
Human Motion ◽  
Compression Tests ◽  
Piezoresistive Sensors ◽  
Human Motion Detection ◽  
Pressure Regime

The high demand for multifunctional devices for smart clothing applications, human motion detection, soft robotics, and artificial electronic skins has encouraged researchers to develop new high-performance flexible sensors. In this work, we fabricated and tested new 3D squeezable Ecoflex® open cell foams loaded with different concentrations of graphene nanoplatelets (GNPs) in order to obtain lightweight, soft, and cost-effective piezoresistive sensors with high sensitivity in a low-pressure regime. We analyzed the morphology of the produced materials and characterized both the mechanical and piezoresistive response of samples through quasi-static cyclic compression tests. Results indicated that sensors infiltrated with 1 mg of ethanol/GNP solution with a GNP concentration of 3 mg/mL were more sensitive and stable compared to those infiltrated with the same amount of ethanol/GNP solution but with a lower GNP concentration. The electromechanical response of the sensors showed a negative piezoresistive behavior up to ~10 kPa and an opposite trend for the 10–40 kPa range. The sensors were particularly sensitive at very low deformations, thus obtaining a maximum sensitivity of 0.28 kPa−1 for pressures lower than 10 kPa.

scholarly journals Highly Sensitive Ultrathin Flexible Thermoplastic Polyurethane/Carbon Black Fibrous Film Strain Sensor with Adjustable Scaffold Networks

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Xin Wang ◽  
Xianhu Liu ◽  
Dirk W. Schubert
Keyword(s):  
Carbon Black ◽  
High Performance ◽  
Electrical Response ◽  
Thermoplastic Polyurethane ◽  
Conductive Polymer ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Motion ◽  
Electrospinning Process ◽  
Gauge Factor

AbstractIn recently years, high-performance wearable strain sensors have attracted great attention in academic and industrial. Herein, a conductive polymer composite of electrospun thermoplastic polyurethane (TPU) fibrous film matrix-embedded carbon black (CB) particles with adjustable scaffold network was fabricated for high-sensitive strain sensor. This work indicated the influence of stereoscopic scaffold network structure built under various rotating speeds of collection device in electrospinning process on the electrical response of TPU/CB strain sensor. This structure makes the sensor exhibit combined characters of high sensitivity under stretching strain (gauge factor of 8962.7 at 155% strain), fast response time (60 ms), outstanding stability and durability (> 10,000 cycles) and a widely workable stretching range (0–160%). This high-performance, wearable, flexible strain sensor has a broad vision of application such as intelligent terminals, electrical skins, voice measurement and human motion monitoring. Moreover, a theoretical approach was used to analyze mechanical property and a model based on tunneling theory was modified to describe the relative change of resistance upon the applied strain. Meanwhile, two equations based from this model were first proposed and offered an effective but simple approach to analyze the change of number of conductive paths and distance of adjacent conductive particles.

A flexible pressure sensor based on rGO/polyaniline wrapped sponge with tunable sensitivity for human motion detection

Nanoscale ◽  
2018 ◽  
Vol 10 (21) ◽  
pp. 10033-10040 ◽  
Author(s):  
Gang Ge ◽  
Yichen Cai ◽  
Qiuchun Dong ◽  
Yizhou Zhang ◽  
Jinjun Shao ◽  
...  
Keyword(s):  
Motion Detection ◽  
High Performance ◽  
Rapid Development ◽  
High Sensitivity ◽  
Human Motion ◽  
The Internet ◽  
Human Motion Detection ◽  
Wearable Electronic ◽  
Flexible Pressure Sensor ◽  
The Internet Of Things

High-performance stretchable and wearable electronic skins (E-skins) with high sensitivity and a large sensing range are urgently required with the rapid development of the Internet of things and artificial intelligence.

scholarly journals High Performance of a Metal Layer-Assisted Guided-Mode Resonance Biosensor Modulated by Double-Grating

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 221
Author(s):  
Chengrui Zhang ◽  
Yi Zhou ◽  
Lan Mi ◽  
Jiong Ma ◽  
Xiang Wu ◽  
...  
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Structural Parameters ◽  
Metal Layer ◽  
High Sensitivity ◽  
Grating Structure ◽  
Surface Sensitivity ◽  
Guided Mode ◽  
Guided Mode Resonance ◽  
Low Sensitivity

Guided-mode resonance (GMR) sensors are widely used as biosensors with the advantages of simple structure, easy detection schemes, high efficiency, and narrow linewidth. However, their applications are limited by their relatively low sensitivity (<200 nm/RIU) and in turn low figure of merit (FOM, <100 1/RIU). Many efforts have been made to enhance the sensitivity or FOM, separately. To enhance the sensitivity and FOM simultaneously for more sensitive sensing, we proposed a metal layer-assisted double-grating (MADG) structure with the evanescent field extending to the sensing region enabled by the metal reflector layer underneath the double-grating. The influence of structural parameters was systematically investigated. Bulk sensitivity of 550.0 nm/RIU and FOM of 1571.4 1/RIU were obtained after numerical optimization. Compared with a single-grating structure, the surface sensitivity of the double-grating structure for protein adsorption increases by a factor of 2.4 times. The as-proposed MADG has a great potential to be a biosensor with high sensitivity and high accuracy.

Determination of Selected Phthalates in Some Commercial Cosmetic Products by HPLC-UV

2020 ◽  
Vol 23 (10) ◽  
pp. 1010-1022
Author(s):  
Emrah Dural
Keyword(s):  
High Performance ◽  
Phthalate Esters ◽  
High Sensitivity ◽  
Hplc Method ◽  
Cosmetic Products ◽  
Limit Of Quantification ◽  
Nail Polish ◽  
Accuracy And Precision ◽  
Butyl Phthalate

Aim and scope: Due to the serious toxicological risks and their widespread use, quantitative determination of phthalates in cosmetic products have importance for public health. The aim of this study was to develop a validated simple, rapid and reliable high-performance liquid chromatography (HPLC) method for the determination of phthalates which are; dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), di(2- ethylhexyl) phthalate (DEHP), in cosmetic products and to investigate these phthalate (PHT) levels in 48 cosmetic products marketing in Sivas, Turkey. Materials and Methods: Separation was achieved by a reverse-phase ACE-5 C18 column (4.6 x 250 mm, 5.0 μm). As the mobile phase, 5 mM KH2PO4 and acetonitrile were used gradiently at 1.5 ml min-1. All PHT esters were detected at 230 nm and the run time was taking 21 minutes. Results: This method showed the high sensitivity value the limit of quantification (LOQ) values for which are below 0.64 μg mL-1 of all phthalates. Method linearity was ≥0.999 (r2). Accuracy and precision values of all phthalates were calculated between (-6.5) and 6.6 (RE%) and ≤6.2 (RSD%), respectively. Average recovery was between 94.8% and 99.6%. Forty-eight samples used for both babies and adults were successfully analyzed by the developed method. Results have shown that, DMP (340.7 μg mL-1 ±323.7), DEP (1852.1 μg mL-1 ± 2192.0), and DBP (691.3 μg mL-1 ± 1378.5) were used highly in nail polish, fragrance and cream products, respectively. Conclusion: Phthalate esters, which are mostly detected in the content of fragrance, cream and nail polish products and our research in general, are DEP (1852.1 μg mL-1 ± 2192.0), DBP (691.3 μg mL-1 ± 1378.5) and DMP (340.7 μg mL-1 ±323.7), respectively. Phthalates were found in the content of all 48 cosmetic products examined, and the most detected phthalates in general average were DEP (581.7 μg mL-1 + 1405.2) with a rate of 79.2%. The unexpectedly high phthalate content in the examined cosmetic products revealed a great risk of these products on human health. The developed method is a simple, sensitive, reliable and economical alternative for the determination of phthalates in the content of cosmetic products, it can be used to identify phthalate esters in different products after some modifications.

scholarly journals Flexible Metal/Polymer Composite Films Embedded with Silver Nanowires as a Stretchable and Conductive Strain Sensor for Human Motion Monitoring

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 372 ◽  
Author(s):  
Jinjin Luan ◽  
Qing Wang ◽  
Xu Zheng ◽  
Yao Li ◽  
Ning Wang
Keyword(s):  
Polymer Composite ◽  
Silver Nanowires ◽  
Composite Films ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Motion ◽  
Applied Strain ◽  
Potential Candidate ◽  
Flexible Metal ◽  
Metal Polymer

To avoid conductive failure due to the cracks of the metal thin film under external loads for the wearable strain sensor, a stretchable metal/polymer composite film embedded with silver nanowires (AgNWs) was examined as a potential candidate. The combination of Ag film and AgNWs enabled the fabrication of a conductive film that was applied as a high sensitivity strain sensor, with gauge factors of 7.1 under the applied strain of 0–10% and 21.1 under the applied strain of 10–30%. Furthermore, the strain sensor was demonstrated to be highly reversible and remained stable after 1000 bending cycles. These results indicated that the AgNWs could act as elastic conductive bridges across cracks in the metal film to maintain high conductivity under tensile and bending loads. As such, the strain sensor engineered herein was successfully applied in the real-time detection and monitoring of large motions of joints and subtle motions of the mouth.

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

Sign in / Sign up

Export Citation Format

Share Document