Piezo-Resistive Properties of Bio-Based Sensor Yarn Made with Sisal Fibre

In this work, a sensor yarn based on a natural sisal yarn containing a non-electro-conductive core impregnated with PVA polymer and coated by PEDOT:PSS polymer as an electro-conductive sheath was investigated. The main objectives include the development of this new sensor yarn as a first step. Then, we look towards the insertion of this sensor yarn into different woven structures followed by the monitoring of the mechanical behaviour of composite materials made with these fibrous reinforcements. The combined effect of the structural geometry and the number of PEDOT:PSS coating layers on the properties of the sensor yarns was investigated. It was found that the number of PEDOT:PSS coating layers could strongly influence the electromechanical behaviours of the sensor yarns. Different methods of characterization were employed on strain-sensor yarns with two and four coating layers of PEDOT:PSS. The piezo-resistive strain-sensor properties of these selected coating layers were evaluated. Cyclic stretching-releasing tests were also performed to investigate the dynamic strain-sensing behavior. The obtained results indicated that gauge factor values can be extracted in three strain regions for two and four coating layers, respectively. Moreover, these strain-sensor yarns showed accurate and stable sensor responses under cyclic conditions. Furthers works are in progress to investigate the mechanism behind these first results of these sisal fibre-based sensors.

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Ultra-thin piezoelectric strain sensor 5 × 5 array integrated on flexible printed circuit for structural health monitoring by 2D dynamic strain sensing

2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS) ◽

10.1109/memsys.2016.7421809 ◽

2016 ◽

Cited By ~ 4

Author(s):

T. Kobayashi ◽

T. Yamashita ◽

N. Makimoto ◽

S. Takamatsu ◽

T. Itoh

Keyword(s):

Structural Health Monitoring ◽

Health Monitoring ◽

Strain Sensor ◽

Dynamic Strain ◽

Strain Sensing ◽

Printed Circuit ◽

Structural Health ◽

Flexible Printed Circuit ◽

Piezoelectric Strain

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Knitted piezoresistive strain sensor performance, impact of conductive area and profile design

Journal of Industrial Textiles ◽

10.1177/1528083719837732 ◽

2019 ◽

Vol 50 (5) ◽

pp. 616-634 ◽

Cited By ~ 3

Author(s):

Rafiu K Raji ◽

Xuhong Miao ◽

Shu Zhang ◽

Yutian Li ◽

Ailan Wan ◽

...

Keyword(s):

Strain Sensor ◽

Gauge Factor ◽

Performance Impact ◽

Rectangular Shape ◽

Sensor Performance ◽

Rectangular Profile ◽

Positive Linear Correlation ◽

Actual Design ◽

Sensor Properties ◽

The Impact

While many of the factors influencing strain sensor properties have been explained in literature, other very important parameters that influence actual design performance of sensors remain obscure. This paper investigates the impact of conductive profile and area design including post fabric treatments such as dyeing and washing on sensor performance. 1 × 1 mock rib was the fabric structure of choice, and silver-plaited nylon was the conductive yarn used in knitting all the samples. Six main polygonal shapes including ellipse, diamond shape, corrugated rectangular shape, rectangular horse shoe, rectangular dough roller shape, and plain rectangular shape were designed and knitted. Plain rectangular profile has been found to deliver the best results characterized by noiseless signals, highest gauge factor, and good result repeatability. The analysis of results also reveals a positive linear correlation between conductive path and initial electrical resistance of a sensor. The inverse is true for the relation between the conductive width values and their corresponding initial resistances. Higher conductive widths led to low initial resistance, and values less than 20 Ω for a sensor could lead to inferior sensor sensitivity. High conductive paths produced high initial resistances, and values within the range of 40–120 Ω could deliver higher sensitivity. This study thus concludes that the optimum aspect ratio range for conductive area to deliver satisfactory sensitivity results is approximately between 24:1 and 77:1 cm. Laundry and dyeing have also been found to result in reduced sensor dimensions, resistance, and sensitivity levels.

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Optimization of 3D Printed Elastomeric Nanocomposites for Flexible Strain Sensing Applications

Volume 1: Advances in Aerospace Technology ◽

10.1115/imece2019-11467 ◽

2019 ◽

Author(s):

Mohammad Abshirini ◽

Mohammad Charara ◽

Mrinal C. Saha ◽

M. Cengiz Altan ◽

Yingtao Liu

Keyword(s):

3D Printing ◽

Strain Sensor ◽

Sensitive Strain ◽

Curing Temperature ◽

Gauge Factor ◽

Strain Sensing ◽

Sensing Applications ◽

Wide Range ◽

Load Rate ◽

3D Printed

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.

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Strain-Sensing Properties of Multi-Walled Carbon Nanotube/Polydimethylsiloxane Composites with Different Aspect Ratio and Filler Contents

Materials ◽

10.3390/ma13112431 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2431 ◽

Cited By ~ 3

Author(s):

Oh-Nyoung Hur ◽

Ji-Hwan Ha ◽

Sung-Hoon Park

Keyword(s):

Carbon Nanotube ◽

Aspect Ratio ◽

Strain Sensor ◽

Strain Sensing ◽

Sensing Properties ◽

Sensor Applications ◽

Aspect Ratios ◽

Multi Walled Carbon Nanotube ◽

Milling Method ◽

Sensor Properties

For filler composite systems used in strain sensor applications, piezoresistive effect, strain hysteresis, and repeatability are critical factors, which have to be clearly evaluated and understood. To investigate the effects of the aspect ratio and content of a multi-walled carbon nanotube (MWCNT) on the strain sensor properties of the composite, MWCNT/Polydimethylsiloxane (PDMS) composites with varying filler contents and aspect ratios were fabricated. In order to uniformly disperse MWCNTs on the polymer matrix, we used a three-roll milling method to generate high shear force for de-bundling MWCNTs. Mechanical and electrical properties of the MWCNT composites were evaluated for each case. In addition, through the cyclic stretching test, we optimized the strain-sensing properties of the MWCNT composites by considering their piezoresistive effects and strain hysteresis.

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Embedded 3D Printing of Highly Flexible Nanocomposites With Piezoresistive Sensing Capabilities

Volume 4: Advances in Aerospace Technology ◽

10.1115/imece2020-23173 ◽

2020 ◽

Author(s):

Blake Herren ◽

Mrinal C. Saha ◽

M. Cengiz Altan ◽

Yingtao Liu

Keyword(s):

3D Printing ◽

Human Skin ◽

Strain Sensor ◽

Strain Range ◽

High Sensitivity ◽

Curing Temperature ◽

Gauge Factor ◽

Strain Sensing ◽

Sensing Applications ◽

Human Joints

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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Embedded carbon nanotube thread piezoresistive strain sensor performance

Sensor Review ◽

10.1108/sr-04-2013-653 ◽

2014 ◽

Vol 34 (2) ◽

pp. 209-219 ◽

Cited By ~ 18

Author(s):

Mark Schulz ◽

Yi Song ◽

Adam Hehr ◽

Vesselin Shanov

Keyword(s):

Carbon Nanotube ◽

Composite Materials ◽

Strain Sensor ◽

Temperature Stability ◽

Gauge Factor ◽

Strain Sensing ◽

Metallic Structures ◽

Content Type ◽

Sensing Properties ◽

Sensor Performance

Purpose – Carbon nanotube (CNT) thread ' s piezoresisitive strain sensing properties of gauge factor, linearity, hysteresis, consistency, temperature stability, and bandwidth were evaluated. This evaluation was motivated by little information in literature combined with the need to understand these properties for commercial use. The paper aims to discuss these issues. Design/methodology/approach – The study here analyzes as-spun CNT thread built into unidirectional glass fiber composites and mounted onto aluminium beams with epoxy to evaluate strain sensing properties. The analyses utilize known sensor parameter definitions to quantify sensor performance. Findings – CNT thread can provide reliable and robust strain measurements for composite and metallic structures. The strain sensor performance meets or exceeds other strain sensors in performance. Research limitations/implications – CNT thread ' s piezoresistive effect is not well understood in terms of Poisson ' s ratio and nanotube contact. More research needs to be carried out to better understand this relationship and optimize the sensor thread. Practical implications – CNT thread can be utilized as a robust strain sensor for composite and metallic structures. It can also be built into composite materials for embedded strain and damage monitoring. By monitoring composite materials with the sensor thread, reliability will significantly increase. In turn, this will lower safety factors and revolutionize inspection methods for composite materials. Originality/value – This paper is the first to comprehensively evaluate key strain sensing properties of CNT thread. With all this strain sensor information in one spot, this should help expedite the use of this technology in other research and industry.

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Piezoresistive Characteristics of Nanocarbon Composite Strain Sensor by Its Longitudinal Pattern Design

Applied Sciences ◽

10.3390/app11135760 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5760

Author(s):

Sung-Yong Kim ◽

Baek-Gyu Choi ◽

Gwang-Won Oh ◽

Chan-Jung Kim ◽

Young-Seok Jung ◽

...

Keyword(s):

Axial Load ◽

Filler Content ◽

Factor Model ◽

Strain Sensor ◽

Gauge Factor ◽

Geometric Pattern ◽

Pattern Design ◽

Macro Scale ◽

Composite Strain ◽

Longitudinal Pattern

For an engineering feasibility study, we studied a simple design to improve NCSS (nanocarbon composite strain sensor) sensitivity by using its geometric pattern at a macro scale. We fabricated bulk- and grid-type sensors with different filler content weights (wt.%) and different sensor lengths and investigated their sensitivity characteristics. We also proposed a unit gauge factor model of NCSS to find a correlation between sensor length and its sensitivity. NCSS sensitivity was improved proportional to its length incremental ratio and we were able to achieve better linear and consistent data from the grid type than the bulk type one. We conclude that the longer sensor length results in a larger change of resistance due to its piezoresistive unit summation and that sensor geometric pattern design is one of the important issues for axial load and deformation measurement.

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Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons

Nanomaterials ◽

10.3390/nano11071701 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1701

Author(s):

Ken Suzuki ◽

Ryohei Nakagawa ◽

Qinqiang Zhang ◽

Hideo Miura

Keyword(s):

Graphene Nanoribbons ◽

Strain Sensor ◽

Strain Sensors ◽

Sensitive Strain ◽

Bending Test ◽

Gauge Factor ◽

Four Point Bending ◽

Current Voltage ◽

Highly Sensitive ◽

Current Voltage Relationship

In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.

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A Novel Textile Stitch-Based Strain Sensor for Wearable End Users

Materials ◽

10.3390/ma12091469 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1469 ◽

Cited By ~ 10

Author(s):

Orathai Tangsirinaruenart ◽

George Stylios

Keyword(s):

Mechanical Properties ◽

Electrical Resistance ◽

Body Movement ◽

Strain Sensor ◽

Strain Sensors ◽

Gauge Factor ◽

Heart Monitoring ◽

Textile Sensors ◽

Good Repeatability ◽

The Ideal

This research presents an investigation of novel textile-based strain sensors and evaluates their performance. The electrical resistance and mechanical properties of seven different textile sensors were measured. The sensors are made up of a conductive thread, composed of silver plated nylon 117/17 2-ply, 33 tex and 234/34 4-ply, 92 tex and formed in different stitch structures (304, 406, 506, 605), and sewn directly onto a knit fabric substrate (4.44 tex/2 ply, with 2.22, 4.44 and 7.78 tex spandex and 7.78 tex/2 ply, with 2.22 and 4.44 tex spandex). Analysis of the effects of elongation with respect to resistance indicated the ideal configuration for electrical properties, especially electrical sensitivity and repeatability. The optimum linear working range of the sensor with minimal hysteresis was found, and the sensor’s gauge factor indicated that the sensitivity of the sensor varied significantly with repeating cycles. The electrical resistance of the various stitch structures changed significantly, while the amount of drift remained negligible. Stitch 304 2-ply was found to be the most suitable for strain movement. This sensor has a wide working range, well past 50%, and linearity (R2 is 0.984), low hysteresis (6.25% ΔR), good gauge factor (1.61), and baseline resistance (125 Ω), as well as good repeatability (drift in R2 is −0.0073). The stitch-based sensor developed in this research is expected to find applications in garments as wearables for physiological wellbeing monitoring such as body movement, heart monitoring, and limb articulation measurement.

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