Ti3C2Tx MXene/polyvinyl alcohol decorated polyester warp knitting fabric for flexible wearable strain sensors

2021 ◽  
pp. 004051752110441
Author(s):  
Qinghua Yu ◽  
Jinhua Jiang ◽  
Chuanli Su ◽  
Yaoli Huang ◽  
Nanliang Chen ◽  
...  

Flexible wearable strain sensors with excellent sensing performance have received widespread interest due to their superior application capability in the field of human-computer interaction, sports rehabilitation, and disease diagnosis. But at present, it is still a considerable challenge to exploit a flexible strain sensor with high sensitivity and wide sensing range that is easily manufactured, low-cost, and easily integrable into clothing. MXene is a promising material sensitive enough for flexible sensors due to its superior conductivity and hydrophilicity. The warp knitting weft insertion textile structure gives the fabric excellent elasticity, making it suitable as a flexible, stretchable substrate. Therefore, utilizing a polyester elastic fabric with a warp knitting weft insertion structure, a fabric strain sensor with high sensitivity and wide sensing range prepared by layer-by-layer self-assembly of polyvinyl alcohol layers and MXene layers is reported in this study. The strain sensor exhibits high sensitivity (up to 288.43), a wide sensing range (up to 50%), fast response time (50 ms), ultra-low detection limit (a strain of 0.067%), excellent cycle stability (1000 cycles), and good washability. Besides, affixing the MXene/polyvinyl alcohol/polyester elastic fabric strain sensor on the joints can detect the movement of limbs. Therefore, the MXene/polyvinyl alcohol/polyester elastic fabric strain sensor demonstrates potential application opportunities in smart wearable electronic devices, and the researcher can also apply this method in the production of other flexible, intelligent wearable devices.

2021 ◽  
Author(s):  
Suresh Nuthalapati ◽  
Vaishakh Kedambaimoole ◽  
Vijay Shirhatti ◽  
Saurabh Kumar ◽  
Hidekuni Takao ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1077 ◽  
Author(s):  
Wei Xu ◽  
Tingting Yang ◽  
Feng Qin ◽  
Dongdong Gong ◽  
Yijia Du ◽  
...  

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.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3962 ◽  
Author(s):  
Mun-Young Hwang ◽  
Dae-Hyun Han ◽  
Lae-Hyong Kang

Carbon nanotube/polymer-based composites have led to studies that enable the realization of low-cost, high-sensitivity piezoresistive strain sensors. This study investigated the characteristics of piezoresistive multi-walled carbon nanotube (MWCNT)/epoxy composite strain sensors subjected to tensile and compressive loads in one direction at relatively small amounts of strain. A patterned sensor was designed to overcome the disadvantage of the load direction sensitivity differences in the existing sensors. The dispersion state of the MWCNTs in the epoxy polymer matrix with the proposed dispersion process was verified by scanning electron microscopy. An MWCNT/epoxy patterned strain sensor and a patch-type strain sensor were directly attached to an acrylic cantilever beam on the opposite side of a commercial metallic strain gauge. The proposed patterned sensor had gauge factors of 2.52 in the tension direction and 2.47 in the compression direction. The measured gauge factor difference for the patterned sensor was less than that for the conventional patch-type sensor. Moreover, the free-vibration frequency response characteristics were compared with those of metal strain gauges to verify the proposed patch-type sensor. The designed drive circuit compensated for the disadvantages due to the high drive voltage, and it was confirmed that the proposed sensor had higher sensitivity than the metallic strain gauge. In addition, the hysteresis of the temperature characteristics of the proposed sensor is presented to show its temperature range. It was verified that the patterned sensor developed through various studies could be applied as a strain sensor for structural health monitoring.


2008 ◽  
Vol 1 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Xue ◽  
Tianhong Cui

We demonstrate a carbon nanotube based high-resolution biosensor for acetylcholine sensing. Carbon nanotubes are deposited on a silicon wafer in a repeated fashion with layer-by-layer nano self-assembly technique. With nano-assembled acetylcholinesterase molecules on the surface, the carbon nanotube biosensor is capable of detecting acetylcholine at an ultra-low concentration of 100 pM. The sensitivity of the acetylcholine sensor is measured as 7.2 µA/decade. The real-time measurement shows the response time of the biosensor is approximately 6 sec. Both the carbon nanotube film and the acetylcholinesterase film are crucial in the sensing process. Due to its high resolution, fast response, small size, and low cost, the carbon nanotube biosensor has tremendous potential for applications in medical research and clinical diagnosis.


Author(s):  
Ryohei Nakagawa ◽  
Zhi Wang ◽  
Ken Suzuki

Health monitoring devices using a strain sensor, which shows high sensitivity and large deformability, are strongly demanded due to further aging of society with fewer children. Conventional strain sensors, such as metallic strain gauges and semiconductive strain sensors, however, aren’t applicable to health monitoring because of their low sensitivity and deformability. In this study, fundamental design of area-arrayed graphene nano-ribbon (GNR) strain senor was proposed in order to fabricate next-generation strain sensor. The sensor was consisted of two sections, which are stress concentration section and stress detecting section. This structure can take full advantage of GNR’s properties. Moreover, high quality GNR fabrication process, which is one of the important process in the sensor, was developed by applying CVD (Chemical Vapor Deposition) method. Top-down approach was applied to fabricate the GNR. At first, in order to synthesize a high-quality graphene sheet, acetylene-based LPCVD (low pressure chemical vapor deposition) using a closed Cu foil was employed. After that, graphene was transferred silicon substrate and the quality was evaluated. The high quality graphene was transferred on the soft PDMS substrate and metallic electrodes were fabricated by applying MEMS technology. Area-arrayed fine pin structure was fabricated by using hard PDMS as a stress-concentration section. Finally, both sections were integrated to form a highly sensitive and large deformable pressure sensor. The strain sensitivity of the GNR-base sensor was also evaluated.


2020 ◽  
Vol 8 (12) ◽  
pp. 4040-4048 ◽  
Author(s):  
Yan Li ◽  
Shan Wang ◽  
Zhi-chao Xiao ◽  
Yi Yang ◽  
Bo-wen Deng ◽  
...  

The layer-by-layer structure formed by the synergistic effect of GO and AgNWs endows the strain sensors with high sensitivity and a wide working range.


2017 ◽  
Vol 5 (31) ◽  
pp. 7746-7752 ◽  
Author(s):  
Xueliang Ye ◽  
Zhen Yuan ◽  
Huiling Tai ◽  
Weizhi Li ◽  
Xiaosong Du ◽  
...  

A novel strain sensor based on reduced graphene oxide with ultra-sensitive and ultra-durable performance was fabricated by the chemical layer-by-layer self-assembly method.


Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6588
Author(s):  
Jun Ho Lee ◽  
Jae Sang Heo ◽  
Keon Woo Lee ◽  
Jae Cheol Shin ◽  
Jeong-Wan Jo ◽  
...  

For wearable health monitoring systems and soft robotics, stretchable/flexible pressure sensors have continuously drawn attention owing to a wide range of potential applications such as the detection of human physiological and activity signals, and electronic skin (e-skin). Here, we demonstrated a highly stretchable pressure sensor using silver nanowires (AgNWs) and photo-patternable polyurethane acrylate (PUA). In particular, the characteristics of the pressure sensors could be moderately controlled through a micro-patterned hole structure in the PUA spacer and size-designs of the patterned hole area. With the structural-tuning strategies, adequate control of the site-specific sensitivity in the range of 47~83 kPa−1 and in the sensing range from 0.1 to 20 kPa was achieved. Moreover, stacked AgNW/PUA/AgNW (APA) structural designed pressure sensors with mixed hole sizes of 10/200 µm and spacer thickness of 800 µm exhibited high sensitivity (~171.5 kPa−1) in the pressure sensing range of 0~20 kPa, fast response (100~110 ms), and high stretchability (40%). From the results, we envision that the effective structural-tuning strategy capable of controlling the sensing properties of the APA pressure sensor would be employed in a large-area stretchable pressure sensor system, which needs site-specific sensing properties, providing monolithic implementation by simply arranging appropriate micro-patterned hole architectures.


2006 ◽  
Vol 45 ◽  
pp. 1828-1833
Author(s):  
Fabio A. Deorsola ◽  
P. Mossino ◽  
Ignazio Amato ◽  
Bruno DeBenedetti ◽  
A. Bonavita ◽  
...  

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.


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