Aligned flexible conductive fibrous networks for highly sensitive, ultrastretchable and wearable strain sensors

2018 ◽  
Vol 6 (24) ◽  
pp. 6575-6583 ◽  
Author(s):  
Guojie Li ◽  
Kun Dai ◽  
Miaoning Ren ◽  
Yan Wang ◽  
Guoqiang Zheng ◽  
...  

A high performance strain sensor based on an aligned conductive fibrous network was prepared with large responsivity, broad sensing range and remarkable stability, demonstrating the applications for detections of both vigorous and subtle human motions.

Author(s):  
Takuya Kudo ◽  
Qinqiang Zhang ◽  
Ken Suzuki ◽  
Hideo Miura

Abstract Graphene nanoribbons (GNRs), nano scale strips of graphene which consists of carbon hexagonal unit cell, are expected as next generation materials for high performance devices because of its unique super-conductive properties. When the strip width of graphene is cut into nano-scale, thinner than 70 nm, however, band gap starts to appear in the thin GNRs at room temperature, and thus, they show semiconductive properties. Previous studies have shown that the bad gap of GNR is highly sensitive to strain, which indicates that GNRs are candidates for a detective element of highly sensitive strain sensors. In practical applications, ohmic contact between a metallic electrode and a semiconductive detective element is indispensable for these sensors. By considering the effect of the width of GNRs on their electronic properties, dumbbell-shape GNRs (DS-GNRs) structures have been proposed for the basic structure of the GNR-base strain sensors, which consisted of GNRs with two different widths. Center portion of the DS-GNR is narrower than 70 nm and GNRs wider than 70 nm are attached at the both ends of the center GNR as electrode. Both semiconductive and metallic portions of a strain sensor consist of only carbon atoms using this DS-GNR structure. Even though this structure consists of one material, the effect of the interaction between two metallic and semiconductive GNRs must be clarified to realize the strain sensor with high performance. In this study, first principle calculations were applied to the analysis of the electronic band structure of the DS-GNR based on density functional theory (DFT). It was found that the local distribution of energy states of electrons and charges varied drastically as strong functions of the length of GNRs and the magnitude of the applied strain. The current through the DS-GNR structure was converged as the length of the semiconductive portion increased. In the models with enough length, transport property of the DS-GNR showed high sensitivity to strain. Thus, the effective resistivity of the structure varied from metallic to semiconductive, and therefore, this structure is appropriate for the next-generation highly sensitive and deformable strain sensors.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Lihua Liu ◽  
Qiang Zhang ◽  
Dong Zhao ◽  
Aoqun Jian ◽  
Jianlong Ji ◽  
...  

Based on the advantages and broad applications of stretchable strain sensors, this study reports a simple method to fabricate a highly sensitive strain sensor with Ag nanomaterials-polydimethylsiloxane (AgNMs-PDMS) to create a synergic conductive network and a sandwich-structure. Three Ag nanomaterial samples were synthesized by controlling the concentrations of the FeCl3 solution and reaction time via the heat polyols thermal method. The AgNMs network’s elastomer nanocomposite-based strain sensors show strong piezoresistivity with a high gauge factor of 547.8 and stretchability from 0.81% to 7.26%. The application of our high-performance strain sensors was demonstrated by the inducting finger of the motion detection. These highly sensitive sensors conform to the current trends of flexible electronics and have prospects for broad application.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1701
Author(s):  
Ken Suzuki ◽  
Ryohei Nakagawa ◽  
Qinqiang Zhang ◽  
Hideo Miura

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.


Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 5884-5890 ◽  
Author(s):  
Zuoli He ◽  
Gengheng Zhou ◽  
Joon-Hyung Byun ◽  
Sang-Kwan Lee ◽  
Moon-Kwang Um ◽  
...  

In this manuscript, we report a novel highly sensitive wearable strain sensor based on a highly stretchable multi-walled carbon nanotube (MWCNT)/Thermoplastic Polyurethane (TPU) fiber obtained via a wet spinning process.


2020 ◽  
Vol 8 (39) ◽  
pp. 20531-20542
Author(s):  
Shuhua Peng ◽  
Shuying Wu ◽  
Yuyan Yu ◽  
Philippe Blanloeuil ◽  
Chun H. Wang

A new highly sensitive and stretchable strain sensor with excellent linearity and optical transparency has been developed by toughening of microcracks within the thin conductive films.


2018 ◽  
Vol 2 (2) ◽  
pp. 355-361 ◽  
Author(s):  
Xi Fan ◽  
Naixiang Wang ◽  
Jinzhao Wang ◽  
Bingang Xu ◽  
Feng Yan

A stretchable plastic strain sensor was fabricated, showing high sensitivity and a broad strain-sensing region with good durability.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2531
Author(s):  
Yelin Ko ◽  
Ji-seon Kim ◽  
Chi Cuong Vu ◽  
Jooyong Kim

Flexible strain sensors are receiving a great deal of interest owing to their prospective applications in monitoring various human activities. Among various efforts to enhance the sensitivity of strain sensors, pre-crack generation has been well explored for elastic polymers but rarely on textile substrates. Herein, a highly sensitive textile-based strain sensor was fabricated via a dip-coat-stretch approach: a polyester woven elastic band was dipped into ink containing single-walled carbon nanotubes coated with silver paste and pre-stretched to generate prebuilt cracks on the surface. Our sensor demonstrated outstanding sensitivity (a gauge factor of up to 3550 within a strain range of 1.5–5%), high stability and durability, and low hysteresis. The high performance of this sensor is attributable to the excellent elasticity and woven structure of the fabric substrate, effectively generating and propagating the prebuilt cracks. The strain sensor integrated into firefighting gloves detected detailed finger angles and cyclic finger motions, demonstrating its capability for subtle human motion monitoring. It is also noteworthy that this novel strategy is a very quick, straightforward, and scalable method of fabricating strain sensors, which is extremely beneficial for practical applications.


Nanoscale ◽  
2018 ◽  
Vol 10 (28) ◽  
pp. 13599-13606 ◽  
Author(s):  
Binghao Liang ◽  
Zhiqiang Lin ◽  
Wenjun Chen ◽  
Zhongfu He ◽  
Jing Zhong ◽  
...  

A highly stretchable and sensitive strain sensor based on a gradient carbon nanotube was developed. The strain sensors show an unprecedented combination of both high sensitivity (gauge factor = 13.5) and ultra-stretchability (>550%).


Soft Matter ◽  
2020 ◽  
Author(s):  
Youqiang Li ◽  
Chuang Liu ◽  
Xue Lv ◽  
shulin sun

Hydrogel-based flexible strain sensors for personal health monitoring and human-machine interaction have attracted wide interest of researchers. In this paper, hydrophobic association and nanocomposite conductive hydrogels were successfully prepared by...


2021 ◽  
Author(s):  
Lu Liu ◽  
Libo Wang ◽  
Xuqing Liu ◽  
Wenfeng Yuan ◽  
Mengmeng Yuan ◽  
...  

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.


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