scholarly journals Skin-Like Strain Sensors Enabled by Elastomer Composites for Human–Machine Interfaces

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 711
Author(s):  
Chunki Yiu ◽  
Tsz Hung Wong ◽  
Yiming Liu ◽  
Kuanming Yao ◽  
Ling Zhao ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Low Cost ◽  
Strain Sensor ◽  
Wearable Electronics ◽  
Mechanical Motion ◽  
Metallic Electrode ◽  
Resistance Change ◽  
Human Machine Interfaces

Flexible electronics exhibit tremendous potential applications in biosensing and human–machine interfaces for their outstanding mechanical performance and excellent electrical characteristics. In this work, we introduce a soft, skin-integrated strain sensor enabled by a ternary elastomer composite of graphene/carbon nanotube (CNT)/Ecoflex, providing a low-cost skin-like platform for conversion of mechanical motion to electricity and sensing of human activities. The device exhibits high sensitivity (the absolute value of the resistance change rate under a testing strain level, 26) and good mechanical stability (surviving ~hundreds of cycles of repeated stretching). Due to the advanced mechanical design of the metallic electrode, the strain sensor shows excellent mechanical tolerance to pressing, bending, twisting, and stretching. The flexible sensor can be directly mounted onto human skin for detecting mechanical motion, exhibiting its great potential in wearable electronics and human–machine interfaces.

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.

Integrated cross-section interface engineering and surface encapsulating strategy: a high-response, waterproof, and low-cost paper-based bending strain sensor

2021 ◽  
Author(s):  
Zaihua Duan ◽  
Yadong Jiang ◽  
Qi Huang ◽  
Qiuni Zhao ◽  
Zhen Yuan ◽  
...  
Keyword(s):  
Cross Section ◽  
Flexible Electronics ◽  
Low Cost ◽  
Strain Sensor ◽  
High Response ◽  
Interface Engineering ◽  
Bending Deformation ◽  
Bending Strain ◽  
Integrated Cross Section

In recent years, the paper-based bending strain (PBS) sensor for bending deformation and angle detections has attracted much attention in flexible electronics. However, the PBS sensor based on the surface...

scholarly journals Realizing Stretchable Aqueous Zn–Based Batteries by Material and Structural Designs

2021 ◽  
Vol 9 ◽  
Author(s):  
Lifeng Hang ◽  
Guihua Jiang
Keyword(s):  
Electrochemical Performance ◽  
Power Supply ◽  
Mechanical Stability ◽  
Low Cost ◽  
Wearable Electronics ◽  
Environmental Friendliness ◽  
Excellent Electrochemical Performance ◽  
Intrinsic Safety

The increasing demands on stretchable power supply for wearable electronics accelerate the development of stretchable batteries. Zn-based batteries are promising to be applied in wearable electronics due to their outstanding performance, intrinsic safety, low cost, and environmental friendliness. Recently, stretchable Zn-based batteries are designed to demonstrate the capability of delivering excellent electrochemical performance, meanwhile maintaining their mechanical stability. This review provides an overview of different strategies and designs to realize stretchability in different Zn-based battery components. The general strategies to realize stretchability are first introduced, followed by the specific designs on the cathode, anode, and electrolytes of Zn batteries. Moreover, current issues and possible strategies are also highlighted.

scholarly journals Printability of the Screen-Printed Strain Sensor with Carbon Black/Silver Paste for Sensitive Wearable Electronics

2020 ◽  
Vol 10 (19) ◽  
pp. 6983
Author(s):  
Xue Qi ◽  
Heebo Ha ◽  
Byungil Hwang ◽  
Sooman Lim
Keyword(s):  
Carbon Black ◽  
Low Cost ◽  
Strain Sensor ◽  
High Volume ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Electronic Products ◽  
Consumer Markets ◽  
Wide Range ◽  
Low Cost Manufacturing

Printing technology enables not only high-volume, multipurpose, low-impact, low-cost manufacturing, but also the introduction of flexible electronic devices, such as displays, actuators, and sensors, to a wide range of consumer markets. Consequently, in the past few decades, printed electronic products have attracted considerable interest. Although flexible printed electronic products are attracting increasing attention from the scientific and industrial communities, a systematic study on their sensing performance based on printability has not been reported so far. In this study, carbon black/Ag nanocomposites were utilized as pastes for a flexible wearable strain sensor. The effects of the rheological property of the pastes and the pattern dimensions of the printed electrodes on the sensor’s performance were investigated. Consequently, the printed sensor demonstrated a high gauge factor of 444.5 for an applied strain of 0.6% to 1.4% with a durability of 1000 cycles and a linearity of R2 = 0.9974. The sensor was also stable under tough environmental conditions.

Design and Development of Biometric Sensor Wearable Band Using Flexible Electronics

2017 ◽  
Author(s):  
Pradeep Lall ◽  
Hao Zhang ◽  
Rahul Lall
Keyword(s):  
Thermal Stress ◽  
Real Time ◽  
Mobile Device ◽  
Flexible Electronics ◽  
Muscle Activity ◽  
Low Cost ◽  
Water Immersion ◽  
Mechanical Shock ◽  
Wearable Electronics ◽  
Medical Electronics

Flexible electronics have a myriad of potential applications in fields such as healthcare, soldier situational awareness, soldier rehabilitation, sports performance, and textile manufacturing among other areas. The primary benefits that flexible electronics provide to both the producers and consumers are their light weight, low power consumption, efficiency, low cost of production, flexibility, and scalability. In comparison to rigid electronics, these systems would be subjected to a greater amount of mechanical and thermal stress in real-time due to their ability to be flexed, rolled, folded, and stretched. Environmental conditions such as bending, mechanical shock, water immersion, sweat, UV radiation, and temperature exposure could degrade the performance of these embedded electronic systems. At this time, there is a lack of suitable test standards and reliability data about flexible electronics manufacturing, assembly, and real-time use. In this paper, a fully flexible medical electronics system was built in full dimension to study the assembly and operation-related failure mechanisms of flexible and wearable electronics. The fabricated flexible electronics system measures pulse and muscle activity, and then transmits this data to a paired mobile device. The pulse rate was measured using an LED and a photo diode, while an electromyography (EMG) sensor was used to measure muscle activity. After collecting the data, the microcontroller sends it to a Bluetooth module, which can in turn transmit this information to a paired mobile device. Through experimentation with the fabricated flexible electronics device, unexpected degradation and quality issues were observed. In flexible PCBs, the space between the IC lead could not be isolated by the solder mask because of its large feature size and as a result, increases the risk of shortage between IC leads when subjected to mechanical stress. In addition, during the assembly process, high reflow temperature was found to subject a huge thermal stress on the connections between the solder pad and copper trace. Proper support of the solder pad should be designed to compensate the thermal stress during the reflow process, and prevent the copper joint on top of the board from being damaged. A set of guidelines for flexible medical electronics and an implementable reliability test standard can, therefore, be established for medical device manufacturers based on these reliability assessments.

scholarly journals Wearable Flexible Strain Sensor Based on Three-Dimensional Wavy Laser-Induced Graphene and Silicone Rubber

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4266 ◽  
Author(s):  
Lixiong Huang ◽  
Han Wang ◽  
Peixuan Wu ◽  
Weimin Huang ◽  
Wei Gao ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Mechanical Performance ◽  
Low Cost ◽  
Three Dimensional ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Polyimide Film ◽  
Gauge Factor ◽  
Joint Movement ◽  
Flexible Strain Sensor

Laser-induced graphene (LIG) has the advantages of one-step fabrication, prominent mechanical performance, as well as high conductivity; it acts as the ideal material to fabricate flexible strain sensors. In this study, a wearable flexible strain sensor consisting of three-dimensional (3D) wavy LIG and silicone rubber was reported. With a laser to scan on a polyimide film, 3D wavy LIG could be synthesized on the wavy surface of a mold. The wavy-LIG strain sensor was developed by transferring LIG to silicone rubber substrate and then packaging. For stress concentration, the ultimate strain primarily took place in the troughs of wavy LIG, resulting in higher sensitivity and less damage to LIG during stretching. As a result, the wavy-LIG strain sensor achieved high sensitivity (gauge factor was 37.8 in a range from 0% to 31.8%, better than the planar-LIG sensor), low hysteresis (1.39%) and wide working range (from 0% to 47.7%). The wavy-LIG strain sensor had a stable and rapid dynamic response; its reversibility and repeatability were demonstrated. After 5000 cycles, the signal peak varied by only 2.32%, demonstrating the long-term durability. Besides, its applications in detecting facial skin expansion, muscle movement, and joint movement, were discussed. It is considered a simple, efficient, and low-cost method to fabricate a flexible strain sensor with high sensitivity and structural robustness. Furthermore, the wavy-LIG strain senor can be developed into wearable sensing devices for virtual/augmented reality or electronic skin.

scholarly journals Mechanical performance of aluminum reinforced wood plastic composites under axial tension: an experimental and numerical investigation

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Longlong Zhao ◽  
Fei Xi ◽  
Xiaorui Wang
Keyword(s):  
Mechanical Performance ◽  
Mechanical Stability ◽  
Low Cost ◽  
Stress Strain ◽  
Wood Plastic Composites ◽  
Plastic Composites ◽  
Axial Tensile ◽  
Residual Curvature ◽  
Strain Relationship ◽  
Weather Resistance

AbstractWood plastic composites (WPCs) are low-cost biomass composite materials with good mechanical stability and good weather resistance that are mainly used in the areas with low stress levels. Aimed at improving the mechanical properties of WPCs, this paper proposes a new WPC reinforced with aluminum. The WPC and aluminum were hot pressed to form an aluminum reinforced wood plastic composites (A-WPC). The axial tensile properties, stress–strain relationship, and failure mechanism of the composite were studied experimentally. The results show that the ultimate stress and strain, elastic modulus, and other mechanical parameters of A-WPCs are much higher than those of WPCs. The elongation at break is 10.13 times that of WPCs, which greatly improves the ductility. Based on the equivalent stiffness theory, two calculation models were proposed to predict the tensile stress–strain relationship of A-WPCs. The tensile rebound process of A-WPCs was analyzed in depth, and then the calculation formula of the residual curvature was deduced to compare with the test results. The experimental results are in good agreement with the calculation results.

Fabrication of 3D Temperature Sensor Using Magnetostrictive Inkjet Printhead

2020 ◽  
Vol 64 (5) ◽  
pp. 50405-1-50405-5
Author(s):  
Young-Woo Park ◽  
Myounggyu Noh
Keyword(s):  
Flexible Electronics ◽  
Inkjet Printing ◽  
Temperature Sensor ◽  
Computer Aided Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Drop On Demand ◽  
Aided Design ◽  
Nanoparticle Ink ◽  
Inkjet Printhead

Abstract Recently, the three-dimensional (3D) printing technique has attracted much attention for creating objects of arbitrary shape and manufacturing. For the first time, in this work, we present the fabrication of an inkjet printed low-cost 3D temperature sensor on a 3D-shaped thermoplastic substrate suitable for packaging, flexible electronics, and other printed applications. The design, fabrication, and testing of a 3D printed temperature sensor are presented. The sensor pattern is designed using a computer-aided design program and fabricated by drop-on-demand inkjet printing using a magnetostrictive inkjet printhead at room temperature. The sensor pattern is printed using commercially available conductive silver nanoparticle ink. A moving speed of 90 mm/min is chosen to print the sensor pattern. The inkjet printed temperature sensor is demonstrated, and it is characterized by good electrical properties, exhibiting good sensitivity and linearity. The results indicate that 3D inkjet printing technology may have great potential for applications in sensor fabrication.

scholarly journals Direct coherent multi-ink printing of fabric supercapacitors

2021 ◽  
Vol 7 (3) ◽  
pp. eabd6978 ◽  
Author(s):  
Jingxin Zhao ◽  
Hongyu Lu ◽  
Yan Zhang ◽  
Shixiong Yu ◽  
Oleksandr I. Malyi ◽  
...  
Keyword(s):  
System Integration ◽  
High Performance ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
High Mass ◽  
Wearable Electronics ◽  
Energy Storage Devices ◽  
Fabrication Procedure ◽  
Self Powered ◽  
Mechanical Devices

Coaxial fiber-shaped supercapacitors with short charge carrier diffusion paths are highly desirable as high-performance energy storage devices for wearable electronics. However, the traditional approaches based on the multistep fabrication processes for constructing the fiber-shaped energy device still encounter persistent restrictions in fabrication procedure, scalability, and mechanical durability. To overcome this critical challenge, an all-in-one coaxial fiber-shaped asymmetric supercapacitor (FASC) device is realized by a direct coherent multi-ink writing three-dimensional printing technology via designing the internal structure of the coaxial needles and regulating the rheological property and the feed rates of the multi-ink. Benefitting from the compact coaxial structure, the FASC device delivers a superior areal energy/power density at a high mass loading, and outstanding mechanical stability. As a conceptual exhibition for system integration, the FASC device is integrated with mechanical units and pressure sensor to realize high-performance self-powered mechanical devices and monitoring systems, respectively.

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