scholarly journals Gold/Polyimide-Based Resistive Strain Sensors

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 565 ◽  
Author(s):  
Tao Han ◽  
Anindya Nag ◽  
Nasrin Afsarimanesh ◽  
Fowzia Akhter ◽  
Hangrui Liu ◽  
...  

This paper presents the fabrication and implementation of novel resistive sensors that were implemented for strain-sensing applications. Some of the critical factors for the development of resistive sensors are addressed in this paper, such as the cost of fabrication, the steps of the fabrication process which make it time-consuming to complete each prototype, and the inability to achieve optimised electrical and mechanical characteristics. The sensors were fabricated via magnetron sputtering of thin-film chromium and gold layer on the thin-film substrates at defined thicknesses. Sticky copper tapes were attached on the two sides of the sensor patches to form the electrodes. The operating principle of the fabricated sensors was based on the change in their responses with respect to the corresponding changes in their relative resistance as a function of the applied strain. The strain-induced characteristics of the patches were studied with different kinds of experiments, such as consecutive bending and pressure application. The sensors with 400 nm thickness of gold layer obtained a sensitivity of 0.0086 Ω/ppm for the pressure ranging between 0 and 400 kPa. The gauge factor of these sensors was between 4.9–6.6 for temperatures ranging between 25 °C and 55 °C. They were also used for tactile sensing to determine their potential as thin-film sensors for industrial applications, like in robotic and pressure-mapping applications. The results were promising in regards to the sensors’ controllable film thickness, easy operation, purity of the films and mechanically sound nature. These sensors can provide a podium to enhance the usage of resistive sensors on a higher scale to develop thin-film sensors for industrial applications.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ahsan Mehmood ◽  
N. M. Mubarak ◽  
Mohammad Khalid ◽  
Priyanka Jagadish ◽  
Rashmi Walvekar ◽  
...  

AbstractStrain sensors in the form of buckypaper (BP) infiltrated with various polymers are considered a viable option for strain sensor applications such as structural health monitoring and human motion detection. Graphene has outstanding properties in terms of strength, heat and current conduction, optics, and many more. However, graphene in the form of BP has not been considered earlier for strain sensing applications. In this work, graphene-based BP infiltrated with polyvinyl alcohol (PVA) was synthesized by vacuum filtration technique and polymer intercalation. First, Graphene oxide (GO) was prepared via treatment with sulphuric acid and nitric acid. Whereas, to obtain high-quality BP, GO was sonicated in ethanol for 20 min with sonication intensity of 60%. FTIR studies confirmed the oxygenated groups on the surface of GO while the dispersion characteristics were validated using zeta potential analysis. The nanocomposite was synthesized by varying BP and PVA concentrations. Mechanical and electrical properties were measured using a computerized tensile testing machine, two probe method, and hall effect, respectively. The electrical conducting properties of the nanocomposites decreased with increasing PVA content; likewise, electron mobility also decreased while electrical resistance increased. The optimization study reports the highest mechanical properties such as tensile strength, Young’s Modulus, and elongation at break of 200.55 MPa, 6.59 GPa, and 6.79%, respectively. Finally, electrochemical testing in a strain range of ε ~ 4% also testifies superior strain sensing properties of 60 wt% graphene BP/PVA with a demonstration of repeatability, accuracy, and preciseness for five loading and unloading cycles with a gauge factor of 1.33. Thus, results prove the usefulness of the nanocomposite for commercial and industrial applications.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Roopa Hegde ◽  
Koona Ramji ◽  
Swapna Peravali ◽  
Yallappa Shiralgi ◽  
Gurumurthy Hegde ◽  
...  

Multiwalled carbon nanotubes (MWCNTs) were synthesized by the reduction of ethyl alcohol with sodium borohydride (NaBH4) under a strong basic solvent with the high concentration of sodium hydroxide (NaOH). Nanocomposites of different concentration of MWCNT dispersed in poly(3,4-ethylene dioxythiophene) polymerized with poly(4-styrene sulfonate) (PEDOT:PSS) were prepared and deposited on a flexible polyethylene terephthalate (PET) polymer substrates by the spin coating method. The thin films were characterized for their nanostructure and subsequently evaluated for their piezoresistive response. The films were subjected to an incremental strain from 0 to 6% at speed of 0.2 mm/min. The nanocomposite thin film with 0.1 wt% of MWCNT exhibits the highest gauge factor of 22.8 at 6% strain as well as the highest conductivity of 13.5 S/m. Hence, the fabricated thin film was found to be suitable for piezoresistive flexible strain sensing applications.


Author(s):  
Mohammad Abshirini ◽  
Mohammad Charara ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan ◽  
Yingtao Liu

Abstract Flexible and sensitive strain sensors can be utilized as wearable sensors and electronic devices in a wide range of applications, such as personal health monitoring, sports performance, and electronic skin. This paper presents the fabrication of a highly flexible and sensitive strain sensor by 3D printing an electrically conductive polydimethylsiloxane (PDMS)/multi-wall carbon nanotube (MWNT) nanocomposite on a PDMS substrate. To maximize the sensor’s gauge factor, the effects of MWNT concentration on the strain sensing function in nanocomposites are evaluated. Critical 3D printing and curing parameters, such as 3D printing nozzle diameter and nanocomposites curing temperature, are explored to achieve the highest piezoresistive response, showing that utilizing a smaller deposition nozzle size and higher curing temperature can result in a higher gauge factor. The optimized 3D printed nanocomposite sensor’s sensitivity is characterized under cyclic tensile loads at different maximum strains and loading rates. A linear piezoresistive response is observed up to 70% strain with an average gauge factor of 12, pointing to the sensor’s potential as a flexible strain sensor. In addition, the sensing function is almost independent of the applied load rate. The fabricated sensors are attached to a glove and used as a wearable sensor by detecting human finger and wrist motion. The results indicate that this 3D printed functional nanocomposite shows promise in a broad range of applications, including wearable and skin mounted sensors.


2015 ◽  
Vol 644 ◽  
pp. 115-119 ◽  
Author(s):  
Sahour Sayed ◽  
Mohammed Gamil ◽  
Ahmed M.R. Fath El-Bab ◽  
Ahmed Abd El Moneim Abd Elmoneim

New technique is developed to synthesize graphene film on flexible substrate for strain sensing applications. A flexible graphene/Poly-ethylene Terephthalate (PET) strain sensor based on graphene piezoresistivity is produced by a new simple low cost technique. Graphene oxide film on PET substrate is reduced and patterned simultaneously using 2 Watt CO2LASER beam. The synthesized graphene film is characterized by XRD, FT-IR, SEM, and Raman techniques. Commercial strain gauges are used to predict experimentally the gauge factor (GF) of the graphene film at different values of applied strain. The stability of the graphene film and its GF are studied at different operating temperatures. The fabricated sensor showed high GF of 78 with great linearity and stability up to 60 °C.


Author(s):  
Tarun Singla ◽  
Amrinder Pal Singh ◽  
Suresh Kumar ◽  
Gagandeep Singh ◽  
Navin Kumar

The usage of nano phase materials for strain sensing applications has attracted attention due to their unique electromechanical properties. The nanocomposite as piezo-resistive films provides an alternative for the realization of strain sensors with high sensitivity than the conventional sensors based on metal and semiconductor strain gauges. In this work, polymer based nano-composite with carbon nanotubes as filler were developed. The multi-walled carbon nanotubes/polystyrene (MWCNTs/PS) nano-composite films were prepared with different wt.% of CNTs using solution mixing method. Field emission scanning electron microscopy technique was carried out to investigate the morphology and dispersion of CNTs in the nano-composite sample. Fourier transform infrared spectroscopy technique was employed to characterize the bonds present in the prepared nano-composite. The electrical response of the composite films was recorded in the form of current-voltage (I-V) characteristics using source meter. The electromechanical response of the nano-composite films with different wt.% of filler CNTs was recorded by applying uni-axial tensile load. The electromechanical responses were then analyzed to obtain gauge factor for the strain sensitivity. The highest gauge factor of 133 was recorded during tensile testing of the nano-composite with 3 wt.% of CNTs fillers.


Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 119
Author(s):  
Farid Sayar Irani ◽  
Ali Hosseinpour Shafaghi ◽  
Melih Can Tasdelen ◽  
Tugce Delipinar ◽  
Ceyda Elcin Kaya ◽  
...  

High accuracy measurement of mechanical strain is critical and broadly practiced in several application areas including structural health monitoring, industrial process control, manufacturing, avionics and the automotive industry, to name a few. Strain sensors, otherwise known as strain gauges, are fueled by various nanomaterials, among which graphene has attracted great interest in recent years, due to its unique electro-mechanical characteristics. Graphene shows not only exceptional physical properties but also has remarkable mechanical properties, such as piezoresistivity, which makes it a perfect candidate for strain sensing applications. In the present review, we provide an in-depth overview of the latest studies focusing on graphene and its strain sensing mechanism along with various applications. We start by providing a description of the fundamental properties, synthesis techniques and characterization methods of graphene, and then build forward to the discussion of numerous types of graphene-based strain sensors with side-by-side tabular comparison in terms of figures-of-merit, including strain range and sensitivity, otherwise referred to as the gauge factor. We demonstrate the material synthesis, device fabrication and integration challenges for researchers to achieve both wide strain range and high sensitivity in graphene-based strain sensors. Last of all, several applications of graphene-based strain sensors for different purposes are described. All in all, the evolutionary process of graphene-based strain sensors in recent years, as well as the upcoming challenges and future directions for emerging studies are highlighted.


Author(s):  
Blake Herren ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan ◽  
Yingtao Liu

Abstract In recent years, highly flexible nanocomposite sensors have been developed for the detection of a variety of human body movements. To precisely detect the bending motions of human joints, the sensors must be able to conform well with the human skin and produce signals that effectively describe the amount of deformation applied to the material during bending. In this paper, a carbon nanotube-based piezoresistive strain sensor is developed via the direct ink writing based embedded 3D printing method. The optimum weight concentration range of carbon nanotubes in the nanocomposite inks, appropriate for embedded 3D printing, is identified. Samples with complex 2D and 3D geometries are printed to demonstrate the manufacturing capabilities of the embedded printing process. The sensitivity of the piezoresistive strain sensor is optimized by determining the ideal nanofiller concentration, curing temperature, and nozzle size to produce the highest gauge factor in a wide strain range. The piezoresistive and mechanical properties of the optimized sensors are fully characterized to verify the suitability for skin-attachable strain sensing applications. The developed sensors have a wide sensing range, high sensitivity, and minimal strain rate dependence. In addition, their low elasticity and high biocompatibility allow them to be comfortably bonded on the human skin.


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