Flexible TPU strain sensors with tunable sensitivity and stretchability by coupling AgNWs with rGO

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.

Download Full-text

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103103 ◽

1988 ◽

Vol 46 ◽

pp. 204-205

Author(s):

Kazumichi Ogura ◽

Michael M. Kersker

Keyword(s):

High Resolution ◽

Layer Structure ◽

High Sensitivity ◽

Beam Current ◽

Electron Beam Current ◽

Lattice Structures ◽

Super Lattice ◽

Different Types ◽

Backscattered Electron ◽

Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

Download Full-text

Giant gauge factor of Van der Waals material based strain sensors

Nature Communications ◽

10.1038/s41467-021-22316-8 ◽

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.

Download Full-text

Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing

Sensors ◽

10.3390/s21124169 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4169

Author(s):

Gennady Gorokh ◽

Natalia Bogomazova ◽

Abdelhafed Taleb ◽

Valery Zhylinski ◽

Timur Galkovsky ◽

...

Keyword(s):

Tungsten Oxide ◽

Gas Sensing ◽

Oxide Films ◽

High Sensitivity ◽

Anodic Alumina ◽

Film Deposition ◽

Silicon Substrates ◽

Layer By Layer ◽

Gas Sensitivity ◽

Nanoporous Anodic Alumina

The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10−3 K−1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively. At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity, which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and low power consumption.

Download Full-text

Capacitive Field-effect (bio-)chemical Sensors Based on Nanocrystalline Diamond Films

MRS Proceedings ◽

10.1557/proc-1203-j17-31 ◽

2009 ◽

Vol 1203 ◽

Author(s):

Matthias Bäcker ◽

Arshak Poghossian ◽

Maryam H. Abouzar ◽

Sylvia Wenmackers ◽

Stoffel D. Janssens ◽

...

Keyword(s):

Thin Films ◽

Field Effect ◽

High Sensitivity ◽

Ph Sensitive ◽

Nanocrystalline Diamond ◽

Penicillin G ◽

Layer By Layer ◽

Label Free ◽

High Coverage ◽

Layer Adsorption

AbstractCapacitive field-effect electrolyte-diamond-insulator-semiconductor (EDIS) structures with O-terminated nanocrystalline diamond (NCD) as sensitive gate material have been realized and investigated for the detection of pH, penicillin concentration, and layer-by-layer adsorption of polyelectrolytes. The surface oxidizing procedure of NCD thin films as well as the seeding and NCD growth process on a Si-SiO2 substrate have been improved to provide high pH-sensitive, non-porous thin films without damage of the underlying SiO2 layer and with a high coverage of O-terminated sites. The NCD surface topography, roughness, and coverage of the surface groups have been characterized by SEM, AFM and XPS methods. The EDIS sensors with O-terminated NCD film treated in oxidizing boiling mixture for 45 min show a pH sensitivity of about 50 mV/pH. The pH-sensitive properties of the NCD have been used to develop an EDIS-based penicillin biosensor with high sensitivity (65-70 mV/decade in the concentration range of 0.25-2.5 mM penicillin G) and low detection limit (5 μM). The results of label-free electrical detection of layer-by-layer adsorption of charged polyelectrolytes are presented, too.

Download Full-text

An interesting 1,4,2,5-dioxadiazine-furazan system: structural modification by incorporating versatile functionalities

Dalton Transactions ◽

10.1039/c7dt02098h ◽

2017 ◽

Vol 46 (41) ◽

pp. 14301-14309 ◽

Cited By ~ 8

Author(s):

Qiong Yu ◽

Guangbin Cheng ◽

Xuehai Ju ◽

Chunxu Lu ◽

Qiuhan Lin ◽

...

Keyword(s):

Structural Modification ◽

Layer Structure ◽

Layer By Layer ◽

Thermal Stabilities

An N-trinitroethylamino derivative and amminonium salt based on the 1,4,2,5-dioxadiazene-furazan system are synthesized and characterized. Due to their layer-by-layer structure, these two compounds show good thermal stabilities and low sensitivities.

Download Full-text

Area-Arrayed Graphene Nano-Ribbon-Base Strain Sensor

Volume 10: Micro- and Nano-Systems Engineering and Packaging ◽

10.1115/imece2018-87277 ◽

2018 ◽

Cited By ~ 2

Author(s):

Ryohei Nakagawa ◽

Zhi Wang ◽

Ken Suzuki

Keyword(s):

Chemical Vapor Deposition ◽

Stress Concentration ◽

Health Monitoring ◽

Vapor Deposition ◽

Strain Sensor ◽

Chemical Vapor ◽

High Sensitivity ◽

Strain Sensors ◽

Chemical Vapor Deposition Method ◽

High Quality

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.

Download Full-text

Note. Reaction of Bacteria Associated with Fish Spoilage to Chemical and Physical Stress

Food Science and Technology International ◽

10.1106/xbyd-ldnf-8ngy-44hg ◽

2001 ◽

Vol 7 (5) ◽

pp. 405-409 ◽

Cited By ~ 1

Author(s):

R. Kirby ◽

M. da Silva ◽

C. Capell ◽

P. Vaz-Pires ◽

P. Gibbs ◽

...

Keyword(s):

Heat Treatment ◽

Synergistic Effect ◽

High Sensitivity ◽

Potassium Sorbate ◽

Bacterial Cells ◽

Chemical Additives ◽

Tetrasodium Pyrophosphate ◽

Chemical Preservative ◽

Brochothrix Thermosphacta ◽

Chemical Preservatives

A cocktail made up of six bacteria isolated from fish was subjected to various heats (30 °C and 60 °C, 20 s) and chemical preservative stresses, alone and in combination. The chemical preservatives tested were potassium sorbate (PS, 1%), trisodium phosphate (TSP, 10%) and tetrasodium pyrophosphate (TSPP, 3%). Heating the bacteria at 60 °C for 20 s resulted in an average reduction of 2.0 log cfu/mL in the total number. The results showed amarked synergistic effect of heat treatment prior to chemical additives, especially for TSPP and sorbate; no significant effect was evident when chemicals were applied alone. The effect was increased by the application of chemical preservatives, before heating, in the decreasing order TSP, TSPP and sorbate; reductions obtained were more than 5.0, 4.0 and 3.0 log cfu/mL, respectively. The synergistic effect observed was dependent on the type of chemical additives used and also on the order of the treatments. Bacteria identified as Shewanella putrefaciens and Pseudomonas putida were more resistant to heat treatment and Brochothrix thermosphacta and Lactobacillus plantarum were more resistant to TSP treatment. These bacteria in the cocktail showed high sensitivity to combined TSP/heat treatment; bacterial cells identified as Enterobacter spp. were the most resistant to this treatment.

Download Full-text

Ti3C2Tx MXene-graphene composite films for wearable strain sensors featured with high sensitivity and large range of linear response

Nano Energy ◽

10.1016/j.nanoen.2019.104134 ◽

2019 ◽

Vol 66 ◽

pp. 104134 ◽

Cited By ~ 17

Author(s):

Yina Yang ◽

Zherui Cao ◽

Peng He ◽

Liangjing Shi ◽

Guqiao Ding ◽

...

Keyword(s):

Linear Response ◽

Large Range ◽

Composite Films ◽

High Sensitivity ◽

Strain Sensors ◽

Graphene Composite

Download Full-text

An efficient PEDOT-coated textile for wearable thermoelectric generators and strain sensors

Journal of Materials Chemistry C ◽

10.1039/c8tc05906c ◽

2019 ◽

Vol 7 (12) ◽

pp. 3496-3502 ◽

Cited By ~ 34

Author(s):

Yanhua Jia ◽

Lanlan Shen ◽

Jing Liu ◽

Weiqiang Zhou ◽

Yukou Du ◽

...

Keyword(s):

High Sensitivity ◽

Strain Sensors ◽

Thermoelectric Generators ◽

Electronic Textiles ◽

Water Durability

Highly flexible PEDOT-based electronic textiles were successfully fabricated for wearable thermoelectric generators and strain sensors with high sensitivity and superior water durability.

Download Full-text