Graphite-Based Bioinspired Piezoresistive Soft Strain Sensors with Performance Optimized for Low Strain Values (original) (raw)
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Piezoresistive Elastomer-Based Composite Strain Sensors and Their Applications
ACS Applied Electronic Materials, 2020
Piezoresistive strain sensors dominate the field of soft elastomer sensors, with many interesting findings and applications. Nevertheless, the methods of characterizing the performance of the sensor differ in each study, leading to different conclusions and comparing with the different sensor systems is challenging. In this attempt, the most important characterization methods of the sensor response are being presented and some cases of elastomer strain sensor are being highlighted. Furthermore, the different materials options for elastomer strain sensors are being shown with a special section for the rapidly growing field of additive manufacturing and 3D printing. Except from the material choices and testing methods, different applications of the strain sensor are presented. From the biomedical field, these soft sensors find
Key Engineering Materials, 2014
A new strain gauge based on graphene piezoresistivity was fabricated by a novel low cost technique which suits mass production of micro piezoresistor sensors. The strain gauge consists of a monolayer graphene film made by chemical vapor deposition on a copper foil surface, and transferred to Si/SiO2 surface by using a polymethyl-methacrylate (PMMA) assisted transfer method. The film is shaped by laser machine to work as a conductive-piezoresistive material between two deposited electrical silver electrodes. This method of fabrication provides a high productivity due to the homogeneous distribution of the graphene monolayer all over the Si/SiO2 surface. The experimentally measured gauge factor of graphene based device is 255, which promises a new strain gauge sensor of high sensitivity.
There is a growing demand for flexible and soft electronic devices. In particular, stretchable, skin-mountable, and wearable strain sensors are needed for several potential applications including personalized health-monitoring, human motion detection, human-machine interfaces, soft robotics, and so forth. This Feature Article presents recent advancements in the development of flexible and stretchable strain sensors. The article shows that highly stretchable strain sensors are successfully being developed by new mechanisms such as disconnection between overlapped nanomaterials, crack propagation in thin films, and tunneling effect, different from traditional strain sensing mechanisms. Strain sensing performances of recently reported strain sensors are comprehensively studied and discussed, showing that appropriate choice of composite structures as well as suitable interaction between functional nanomaterials and polymers are essential for the high performance strain sensing. Next, simulation results of piezoresistivity of stretchable strain sensors by computational models are reported. Finally, potential applications of flexible strain sensors are described. This survey reveals that flexible, skin-mountable, and wearable strain sensors have potential in diverse applications while several grand challenges have to be still overcome.
A facile approach to fabricate graphene based piezoresistive strain sensor on paper substrate
2018
Sensors, FETs and chemi resistors are few of the devices which show potential in the area of flexible electronics for health monitoring applications. In the present work, piezoresistive strain sensors based on graphite and graphene on cellulose paper substrate has been reported. Graphite sensor has been fabricated by rubbing pencil on paper and graphene sensor by directly coating graphene ink using paint brush. The resistance of the fabricated sensor increases with outwards bending and vice-versa, further the piezoresistive effect has also been evaluated by applying variable longitudinal stress. A comparative study of gauge factor (GF) depending upon different type of strains has been presented and it has been observed that the GF of graphene piezoresistive strain sensor decreases with increase in number of layers, the GF for graphene sensor is higher as compared to graphite sensor. Fabricated piezoresistive strain sensors may find applications as human body motion detection, gait a...
A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ∼10 3) graphite nanobelt thin films deposited by a modified Langmuir–Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain– release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing. S Online supplementary data available from stacks.iop.org/NANO/27/375501/mmedia
Polymer-Based Flexible Strain Sensor
Procedia Chemistry, 2009
The design and characterization of polymer-based flexible strain sensors is presented. Characteristics as lightness and flexibility make them suitable for the measure of strain. Several sensors have been realized to analyze the influence of size and electrical conductivity on their behavior. Elongation and applied charge have been precisely controlled in order to measure different parameters as electrical resistance, gauge factor (GF), hysteresis and repeatability. The results clearly show the influence of size and electrical conductivity on the gauge factor, but it is also important to point out the necessity of controlling the hysteresis and repeatability of the response for precision demanding applications.
IEEE sensors letters, 2017
This article reports on a helical spring-like piezoresistive graphene strain sensor formed within a microfluidic channel. The helical spring has a tubular hollow structure and is made of a thin graphene layer coated on the inner wall of the channel using an in situ microfluidic casting method. The helical shape allows the sensor to flexibly respond to both tensile and compressive strains in a wide dynamic detection range from 24% compressive strain to 20% tensile strain. Fabrication of the sensor involves embedding a helical thin metal wire with a plastic wrap into a precursor solution of an elastomeric polymer, forming a helical microfluidic channel by removing the wire from cured elastomer, followed by microfluidic casting of a graphene thin layer directly inside the helical channel. The wide dynamic range, in conjunction with mechanical flexibility and stretchability of the sensor, will enable practical wearable strain sensor applications where large strains are often involved.
Nanomaterials
With the recent great progress made in flexible and wearable electronic materials, the upcoming next generation of skin-mountable and implantable smart devices holds extensive potential applications for the lifestyle modifying, including personalized health monitoring, human-machine interfaces, soft robots, and implantable biomedical devices. As a core member within the wearable electronics family, flexible strain sensors play an essential role in the structure design and functional optimization. To further enhance the stretchability, flexibility, sensitivity, and electricity performances of the flexible strain sensors, enormous efforts have been done covering the materials design, manufacturing approaches and various applications. Thus, this review summarizes the latest advances in flexible strain sensors over recent years from the material, application, and manufacturing strategies. Firstly, the critical parameters measuring the performances of flexible strain sensors and material...