High Effective Sensitivity, Wide Working Range of Melt-blown Nonwoven Conductive Substrates for Smart Wearable Strain Sensors

2021 ◽  
Author(s):  
Jingfang Liu ◽  
Rangtong Liu ◽  
Shuping Liu ◽  
Liang Li ◽  
Shujing Li
Keyword(s):  
Strain Range ◽  
High Sensitivity ◽  
Fast Response ◽  
Strain Sensors ◽  
Gauge Factor ◽  
High Durability ◽  
Voice Changes ◽  
Conductive Substrates ◽  
Smart Wearable ◽  
Melt Blown Nonwoven

Abstract High sensitivity, wide working range and flexible portability of strain sensors are crucial for smart wearable applications. To obtain these performances, several elastic melt-blown nonwoven substrates with excellent flexibility and high conductivity were developed by loading with polypyrrole through a double-dipping and double-rolling finishing method. The structure and conductivity are characterized by scanning electron microscope, infrared spectrometer, digital source meter and so on. The results indicate that the conductivity of prepared substrates is affected by the pyrrole concentration and polypyrrole amount deposited in nonwovens. Obviously, the conductivity and sensitivity of substrates as strain sensors are highly and positively correlated to the fiber orientation in nonwovens, and the effective working range and corresponding sensitivity of sensors are determined by the elastic deformation interval of melt-blown substrate. When the pyrrole concentration is 5.5%, the nonwoven substrate with 45.30% porosity possesses the anisotropic optimal conductivity with 23.491 S m-1 along winding direction and 15.063 S m-1 along width direction. Moreover, the as-prepared flexible conductive substrate exhibits the characteristics of wide working strain range (0-24.2%), high sensitivity with 1.94 gauge factor at the range, fast response (0.023 s), tiny hysteresis (0.011s), high durability and stability after 1000 cycles. Furthermore, the as-prepared sensor provides an effective method to prepare smart wearable strain sensors used as the monitor of finger bending in details and the precise recognition of human voice changes.

scholarly journals High-Performance Wearable Strain Sensor Based on MXene@Cotton Fabric with Network Structure

2021 ◽  
Author(s):  
Lu Liu ◽  
Libo Wang ◽  
Xuqing Liu ◽  
Wenfeng Yuan ◽  
Mengmeng Yuan ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
High Performance ◽  
Mechanical Performance ◽  
Active Material ◽  
Large Body ◽  
Strain Sensor ◽  
Strain Range ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Gauge Factor

Abstract Although 2D nanomaterials such as MXene Ti3C2Tx have been used in flexible electronic devices for their unique properties such as high conductivity, excellent mechanical performance, flexibility, and good hydrophilicity, less research has focused on of MXene-based cotton fabric strain sensors. Moreover, fabrication of wearable strain sensors with a low cost, high sensitivity, good biocompatibility, and broad sensing range is still a challenge. In this work, a high-performance wearable strain sensor composed of 2D MXene d-Ti3C2Tx nanomaterials and cotton fabric is reported. As the active material in the sensor, MXene d-Ti3C2Tx exhibited an excellent conductivity and hydrophilicity and adhered well to the fabric fibers by electrostatic adsorption. Due to the unique structure of the fabric substrate and the properties of MXene sheets, the fabricated pressure sensor achieved a high sensitivity. The gauge factor of the MXene@cotton fabric strain sensor reached up to 4.11 within the strain range of 15 %. Meanwhile, the sensor possessed high durability (>500 cycles) and a low strain detection limit of 0.3%. Finally, the encapsulated strain sensor was used to detect subtle or large body movements and exhibited a rapid response. This study shows that the MXene@cotton fabric strain sensor reported here have great potential for use in flexible, comfortable, and wearable devices for health monitoring and motion detection.

scholarly journals Nano-Cracked Strain Sensor with High Sensitivity and Linearity by Controlling the Crack Arrangement

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2834 ◽  
Author(s):  
Hyunsuk Jung ◽  
Chan Park ◽  
Hyunwoo Lee ◽  
Seonguk Hong ◽  
Hyonguk Kim ◽  
...  
Keyword(s):  
Pulse Wave ◽  
Wearable Sensors ◽  
Strain Sensor ◽  
Strain Range ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Micro Deformation ◽  
Sensing Performance ◽  
Limited Sensitivity

Studies on wearable sensors that monitor various movements by attaching them to a body have received considerable attention. Crack-based strain sensors are more sensitive than other sensors. Owing to their high sensitivity, these sensors have been investigated for measuring minute deformations occurring on the skin, such as pulse. However, existing studies have limited sensitivity at low strain range and nonlinearity that renders any calibration process complex and difficult. In this study, we propose a pre-strain and sensor-extending process to improve the sensitivity and linearity of the sensor. By using these pre-strain and sensor-extending processes, we were able to control the morphology and alignment of cracks and regulate the sensitivity and linearity of the sensor. Even if the sensor was fabricated in the same manner, the sensor that involved the pre-strain and extending processes had a sensitivity 100 times greater than normal sensors. Thus, our crack-based strain sensor had high sensitivity (gauge factor > 5000, gauge factor (GF = (△R/R0)/ε), linearity, and low hysteresis at low strain (<1% strain). Given its high sensing performance, the sensor can be used to measure micro-deformation, such as pulse wave and voice.

scholarly journals A Sprayed Graphene Pattern-Based Flexible Strain Sensor with High Sensitivity and Fast Response

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1077 ◽  
Author(s):  
Wei Xu ◽  
Tingting Yang ◽  
Feng Qin ◽  
Dongdong Gong ◽  
Yijia Du ◽  
...  
Keyword(s):  
Strain Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Strain Sensors ◽  
Biomedical Science ◽  
Gauge Factor ◽  
Experimental Conditions ◽  
Simple Method ◽  
Wide Range ◽  
Flexible Strain Sensor

Flexible strain sensors have a wide range of applications in biomedical science, aerospace industry, portable devices, precise manufacturing, etc. However, the manufacturing processes of most flexible strain sensors previously reported have usually required high manufacturing costs and harsh experimental conditions. Besides, research interests are often focused on improving a single attribute parameter while ignoring others. This work aims to propose a simple method of manufacturing flexible graphene-based strain sensors with high sensitivity and fast response. Firstly, oxygen plasma treats the substrate to improve the interfacial interaction between graphene and the substrate, thereby improving device performance. The graphene solution is then sprayed using a soft PET mask to define a pattern for making the sensitive layer. This flexible strain sensor exhibits high sensitivity (gauge factor ~100 at 1% strain), fast response (response time: 400–700 μs), good stability (1000 cycles), and low overshoot (<5%) as well. Those processes used are compatible with a variety of complexly curved substrates and is expected to broaden the application of flexible strain sensors.

scholarly journals A Practical Strain Sensor Based on Ecoflex/Overlapping Graphene/Ecoflex Sandwich Structures for Vocal Fold Vibration and Body Motion Monitoring

2022 ◽  
Vol 2 ◽  
Author(s):  
Yanyan Fan ◽  
Hongbin Zhao ◽  
Yifan Yang ◽  
Yi Yang ◽  
Tianling Ren ◽  
...  
Keyword(s):  
Structural Design ◽  
Strain Sensor ◽  
Strain Range ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Body Motion ◽  
Gauge Factor ◽  
Sensing Element ◽  
Structure Deformation ◽  
Vocal Fold Vibration

Graphene-based stretchable and flexible strain sensors are one of the promising “bridges” to the biomedical realm. However, enhancing graphene-based wearable strain sensors to meet the demand of high sensitivity, broad sensing range, and recoverable structure deformation simultaneously is still a great challenge. In this work, through structural design, we fabricated a simple Ecoflex/Overlapping Graphene/Ecoflex (EOGE) strain sensor by encapsulating a graphene sensing element on polymer Ecoflex substrates using a drop-casting method. The EOGE strain sensor can detect stretching with high sensitivity, a maximum gauge factor of 715 with a wide strain range up to 57%, and adequate reliability and stability over 1,000 cycles for stretching. Moreover, the EOGE strain sensor shows recoverable structure deformation, and the sensor has a steady response in the frequency disturbance test. The good property of the strain sensor is attributed to the resistance variation induced by the overlap and crack structure of graphene by structural design. The vibrations caused by sound and various body movements have been thoroughly detected, which exhibited that the EOGE strain sensor is a promising candidate for wearable biomedical electronic applications.

scholarly journals Giant gauge factor of Van der Waals material based strain sensors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjie Yan ◽  
Huei-Ru Fuh ◽  
Yanhui Lv ◽  
Ke-Qiu Chen ◽  
Tsung-Yin Tsai ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Large Range ◽  
Van Der Waals ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Strain Gauges ◽  
Gauge Factor ◽  
Proof Of Concept ◽  
High Flexibility ◽  
Small Deformations

AbstractThere is an emergent demand for high-flexibility, high-sensitivity and low-power strain gauges capable of sensing small deformations and vibrations in extreme conditions. Enhancing the gauge factor remains one of the greatest challenges for strain sensors. This is typically limited to below 300 and set when the sensor is fabricated. We report a strategy to tune and enhance the gauge factor of strain sensors based on Van der Waals materials by tuning the carrier mobility and concentration through an interplay of piezoelectric and photoelectric effects. For a SnS2 sensor we report a gauge factor up to 3933, and the ability to tune it over a large range, from 23 to 3933. Results from SnS2, GaSe, GeSe, monolayer WSe2, and monolayer MoSe2 sensors suggest that this is a universal phenomenon for Van der Waals semiconductors. We also provide proof of concept demonstrations by detecting vibrations caused by sound and capturing body movements.

scholarly journals Robust Conductive Hydrogels with Ultrafast Self-Recovery and Nearly Zero Response Hysteresis for Epidermal Sensors

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1854
Author(s):  
Xiuru Xu ◽  
Chubin He ◽  
Feng Luo ◽  
Hao Wang ◽  
Zhengchun Peng
Keyword(s):  
Guar Gum ◽  
Strain Range ◽  
Sio2 Nanoparticles ◽  
Fast Response ◽  
Gauge Factor ◽  
Practical Applications ◽  
Hydroxypropyl Guar ◽  
Stable Chemical ◽  
Conductive Hydrogel ◽  
Conductive Hydrogels

Robust conductive hydrogels are in great demand for the practical applications of smart soft robots, epidermal electronics, and human–machine interactions. We successfully prepared nanoparticles enhanced polyacrylamide/hydroxypropyl guar gum/acryloyl-grafted chitosan quaternary ammonium salt/calcium ions/SiO2 nanoparticles (PHC/Ca2+/SiO2 NPs) conductive hydrogels. Owing to the stable chemical and physical hybrid crosslinking networks and reversible non-covalent interactions, the PHC/Ca2+/SiO2 NPs conductive hydrogel showed good conductivity (~3.39 S/m), excellent toughness (6.71 MJ/m3), high stretchability (2256%), fast self-recovery (80% within 10 s, and 100% within 30 s), and good fatigue resistance. The maximum gauge factor as high as 66.99 was obtained, with a wide detectable strain range (from 0.25% to 500% strain), the fast response (25.00 ms) and recovery time (86.12 ms), excellent negligible response hysteresis, and good response stability. The applications of monitoring the human’s body movements were demonstrated, such as wrist bending and pulse tracking.

scholarly journals Controllable Fabrication of Percolative Metal Nanoparticle Arrays Applied for Quantum Conductance-Based Strain Sensors

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4838
Author(s):  
Zhengyang Du ◽  
Ji’an Chen ◽  
Chang Liu ◽  
Chen Jin ◽  
Min Han
Keyword(s):  
Electron Tunneling ◽  
Electrical Conductance ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Metal Nanoparticle ◽  
Gauge Factor ◽  
Electron Conduction ◽  
Percolation Clusters ◽  
Interdigital Electrodes ◽  
Controllable Fabrication

We use gas phase deposition of well-defined nanoparticles (NPs) to fabricate closely-spaced Pd NP arrays on flexible membranes prepatterned with interdigital electrodes (IDEs). The evolution of the morphology and electron conductance of the NP arrays during deposition is analyzed. The growth of two-dimensional percolation clusters of interconnected NPs, which correlate with the percolation pathway for electron conduction in the NP deposits, is demonstrated. The percolative nature of the NP arrays permits us to finely control the percolation geometries and conductance of the NP film by controlling the NP deposition time so as to realize a precise and reproducible fabrication of sensing materials. Electron transport measurements reveal that the electrical conductance of the NP films is dominated by electron tunneling or hopping across the NP percolating networks. Based on the percolative and quantum tunneling nature, the closely-spaced Pd NP films on PET membranes are used as flexible strain sensors. The sensor demonstrates an excellent response ability to distinguish tiny deformations down to 5×10−4 strain and a high sensitivity with a large gauge factor of 200 up to 4% applied strain.

Highly sensitive and stretchable strain sensors based on chopped carbon fibers sandwiched between silicone rubber layers for human motion detections

2019 ◽  
Vol 54 (3) ◽  
pp. 423-434 ◽  
Author(s):  
MB Azizkhani ◽  
Sh Rastgordani ◽  
A. Pourkamali Anaraki ◽  
J Kadkhodapour ◽  
B Shirkavand Hadavand
Keyword(s):  
Carbon Fibers ◽  
Motion Detection ◽  
Silicone Rubber ◽  
Low Cost ◽  
High Sensitivity ◽  
Human Motion ◽  
Strain Sensors ◽  
Body Motion ◽  
Gauge Factor ◽  
Human Motion Detection

Tuning the electromechanical performance in piezoresistive composite strain sensors is primarily attained through appropriately employing the materials system and the fabrication process. High sensitivity along with flexibility in the strain sensing devices needs to be met according to the application (e.g. human motion detection, health and sports monitoring). In this paper, a highly stretchable and sensitive strain sensor with a low-cost fabrication is proposed which is acquired by embedding the chopped carbon fibers sandwiched in between silicone rubber layers. The electrical and mechanical features of the sensor were characterized through stretch/release loading tests where a considerably high sensitivity (the gauge factor about 100) was observed with very low hysteresis. This implies high strain reversibility (i.e. full recovery in each cycle) over 700 loading cycles. Moreover, the sensors exhibited ultra-high stretchability (up to ∼300% elongation) in addition to a low stiffness meaning minimal mechanical effects induced by the sensor for sensitive human motion monitoring applications including large and small deformations. The results suggest the promising capability of the present sensor in reflecting the human body motion detection.

scholarly journals Printed Strain Sensors Based on an Intermittent Conductive Pattern Filled with Resistive Ink Droplets

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4181 ◽  
Author(s):  
Daniel Zymelka ◽  
Takahiro Yamashita ◽  
Xiuru Sun ◽  
Takeshi Kobayashi
Keyword(s):  
Strain Range ◽  
Functional Materials ◽  
Cost Effective ◽  
Hybrid Structure ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Strain Sensitivity ◽  
Sensor Design ◽  
Good Strain ◽  
Single Droplets

In this study, we demonstrate a strain sensor fabricated as a hybrid structure of a conductive intermittent pattern with embedded single droplets of a functional resistive ink. The main feature of our proposed sensor design is that although the intermittent pattern comprises the majority of the entire sensor area, the strain sensitivity depends almost selectively on the resistive droplets. This opens up the possibility for fast and inexpensive evaluation of sensors manufactured from various functional materials. As the use of resistive ink was limited to single droplets deposition, the required ink amount needed to build a sensor can be considerably reduced. This makes the sensors cost-effective and simple for fabrication. In this study, our proposed sensor design was evaluated when a carbon-based ink was used as the resistive material incorporated into an intermittent structure made of silver. The developed strain sensors were tested during bending deformations demonstrating good strain sensitivity (gauge factor: 7.71) and no hysteresis within the investigated strain range.

scholarly journals High-Performance Wearable Strain Sensor Based on MXene@Cotton Fabric with Network Structure

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 889
Author(s):  
Lu Liu ◽  
Libo Wang ◽  
Xuqing Liu ◽  
Wenfeng Yuan ◽  
Mengmeng Yuan ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
High Performance ◽  
Mechanical Performance ◽  
Active Material ◽  
Large Body ◽  
Strain Sensor ◽  
Strain Range ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
High Durability

Flexible and comfortable wearable electronics are as a second skin for humans as they can collect the physiology of humans and show great application in health and fitness monitoring. MXene Ti3C2Tx have been used in flexible electronic devices for their unique properties such as high conductivity, excellent mechanical performance, flexibility, and good hydrophilicity, but less research has focused on MXene-based cotton fabric strain sensors. In this work, a high-performance wearable strain sensor composed of two-dimensional (2D) MXene d-Ti3C2Tx nanomaterials and cotton fabric is reported. Cotton fabrics were selected as substrate as they are comfortable textiles. As the active material in the sensor, MXene d-Ti3C2Tx exhibited an excellent conductivity and hydrophilicity and adhered well to the fabric fibers by electrostatic adsorption. The gauge factor of the MXene@cotton fabric strain sensor reached up to 4.11 within the strain range of 15%. Meanwhile, the sensor possessed high durability (>500 cycles) and a low strain detection limit of 0.3%. Finally, the encapsulated strain sensor was used to detect subtle or large body movements and exhibited a rapid response. This study shows that the MXene@cotton fabric strain sensor reported here have great potential for use in flexible, comfortable, and wearable devices for health monitoring and motion detection.

Sign in / Sign up

Export Citation Format

Share Document