CARBON NANOCOMPOSITE COATED TEXTILE-BASED SENSOR: SENSING MECHANISM AND DURABILITY

2021 ◽  
Author(s):  
AMIT CHAUDHARI ◽  
SAGAR DOSHI ◽  
MADISON WEISS ◽  
DAE HAN SUNG ◽  
ERIK THOSTESON
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrical Resistance ◽  
Wearable Sensors ◽  
Composite Films ◽  
Large Change ◽  
Dip Coating ◽  
Porous Coating ◽  
Sensing Mechanism ◽  
Smart Garments

Carbon nanotube (CNT) composite films are deposited onto stretchable knit fabrics using electrophoretic deposition (EPD) and dip-coating techniques, which are industrially scalable processes for producing future wearable sensors. The deposited CNTs create an electrically conductive nanocomposite film on the surface of the fibers. These nanocomposite coated fabrics exhibit piezoresistive properties; under mechanical deformation/stretching, a large change in the electrical resistance is observed. Polyethyleneimine (PEI) functionalized carbon nanotubes deposited using EPD create a uniform, extremely thin porous coating on the fiber. Initial results show ultrahigh sensitivity of the carbon nanotube coated fabric when tested on elbow/knee to detect range of motion. The sensitivity of these sensors is exceptionally high when compared to a typical carbon nanotube-based polymer nanocomposite. The nanocomposite coating does not affect fabric's breathability or flexibility, making the sensor comfortable to wear. Because of these unique properties, tremendous potential exists for their use in functional/smart garments. Changes in electrical resistance for these fabrics are influenced by a combination of electron tunneling between the carbon nanotubes and the microstructure of the fabric. To investigate and characterize the unique sensing mechanism, the nanotube coated knit fabric's electromechanical response is studied at different length scales, from individual yarns to fabric levels. For applications in wearable sensors, the durability of the nanotube coating on the fabric is critical for repeatable and reliable sensing response. Durability testing of the sensing fabric for washing loads was conducted to study the nanotube coating's robustness. CNT coating's adhesion quality is evaluated based on the weight loss in the specimen and loss in electrical conductivity in each wash cycle. This research addresses the potential of these sensors for functional/smart garments by examining the underlying mechanism of the sensor response and the durability of the carbon nanotube coating.

scholarly journals Explosive Molecule Sensing at Lattice Defect Sites in Metallic Carbon Nanotubes

2021 ◽  
Author(s):  
Manasi Doshi ◽  
Eric Paul Fahrenthold
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Experimental Research ◽  
Gas Sensing ◽  
Lattice Defect ◽  
Sensing Mechanism ◽  
Defect Sites ◽  
Chemiresistive Sensing ◽  
Hazardous Gas

Explosives and hazardous gas sensing using carbon nanotube (CNT) based sensors has been a focus of considerable experimental research. The simplest sensors have employed a chemiresistive sensing mechanism, and rely...

scholarly journals A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Waris Obitayo ◽  
Tao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Strain Sensors ◽  
Voltage Response ◽  
Strain Sensing ◽  
Multiwalled Carbon ◽  
Sensing Applications ◽  
Mechanical Deformations ◽  
Electrical Resistivities

The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

Mechanical Properties Of Polyaniline / Multi-walled Carbon Nanotube Composite Films

2003 ◽  
Vol 791 ◽  
Author(s):  
P. C. Ramamurthy ◽  
W. R. Harrell ◽  
R. V. Gregory ◽  
B. Sadanadan ◽  
A. M. Rao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Weight Percent ◽  
Organic Electronic Devices ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotube ◽  
Contact Devices ◽  
Carbon Nanotube Composite

ABSTRACTHigh molecular weight polyaniline / multi-walled carbon nanotube composite films were fabricated using solution processing. Composite films with various weight percentages of multiwalled carbon nanotubes were fabricated. Physical properties of these composites were analyzed by thermogravimetric analysis, tensile testing, and scanning electron microscopy. These results indicate that the addition of multiwalled nanotubes to polyaniline significantly enhances the mechanical properties of the films. In addition, metal–semiconductor (composite) (MS) contact devices were fabricated, and it was observed that the current level in the films increased with increasing multiwalled nanotube content. Furthermore, it was observed that polyaniline containing one weight percent of carbon nanotubes appears to be the most promising composition for applications in organic electronic devices.

The Effect of Nanotube Loading and Dispersion on the Three-Dimensional Nanostructure of Carbon Nanotube-Conducting Polymer Composite Films

2002 ◽  
Vol 739 ◽  
Author(s):  
Mark Hughes ◽  
George Z. Chen ◽  
Milo S. P. Shaffer ◽  
Derek J. Fray ◽  
Alan H. Windle
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Conducting Polymer ◽  
Polymer Composite ◽  
Electrochemical Polymerization ◽  
Composite Films ◽  
Three Dimensional ◽  
Ionic Diffusion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTNanoporous composite films of multi-walled carbon nanotubes (MWNTs) and either polypyrrole (PPy) or poly(3-methylthiophene) (P3MeT) were grown using an electrochemical polymerization technique in which the nanotubes and conducting polymer were deposited simultaneously. The concentration and dispersion of MWNTs in the polymerization electrolyte was found to have a significant effect on the thickness of polymer coated on each MWNT and hence the loading of MWNTs in the films produced. It has been shown that for an increasing concentration of MWNTs in the polymerization electrolyte, the thickness of polymer coated on each MWNT decreases. This relationship made it possible to minimize ionic diffusion distances within the nanoporous MWNT-PPy films produced, reducing their electrical and ionic resistance and increasing their capacitance relative to similarly prepared pure PPy films.

On finding of high piezoresistive response of carbon nanotube films without surfactants for in-plane strain detection

2011 ◽  
Vol 22 (18) ◽  
pp. 2155-2159 ◽  
Author(s):  
Y. Miao ◽  
L. Chen ◽  
Y. Lin ◽  
R. Sammynaiken ◽  
W. J. Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Plane Strain ◽  
Composite Films ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Experimental Discovery ◽  
Strain Detection ◽  
Nanotube Films

The use of carbon nanotubes (CNTs) for construction of sensors is promising. This is due to some unique characteristics of CNTs. In recent years, strain sensors built from CNT composite films have been developed; however, their low piezoresistive sensitivity (gauge factor (GF)) in in-plane strain detection is a concern compared with other strain sensors. This article reports an experimental discovery of the superior piezoresistive response of a CNT film that is free of surfactants, known as the pure CNT film. The mechanism for the high GF with the pure CNT film strain sensors is also discussed.

Highly Organized Carbon Nanotube-PDMS Hybrid System for Multifunctional Flexible Devices

2007 ◽  
Author(s):  
Yung J. Jung ◽  
Laila Jaber-Ansari ◽  
Xugang Xiong ◽  
Sinan Mu¨ftu¨ ◽  
Ahmed Busnaina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Fields ◽  
Composite Structures ◽  
Field Enhancement ◽  
Chemical Vapor ◽  
Casting Process ◽  
Dip Coating ◽  
Network Architectures ◽  
Multiwalled Carbon

We will present a method to fabricate a new class of hybrid composite structures based on highly organized multiwalled carbon nanotube (MWNT) and singlewalled carbon nanotube (SWNT) network architectures and a polydimethylsiloxane (PDMS) matrix for the prototype high performance flexible systems which could be used for many daily-use applications. To build 1–3 dimensional highly organized network architectures with carbon nanotubes (both MWNT and SWNT) in macro/micro/nanoscale we used various nanotube assembly processes such as selective growth of carbon nanotubes using chemical vapor deposition (CVD) and self-assembly of nanotubes on the patterned trenches through solution evaporation with dip coating. Then these vertically or horizontally aligned and assembled nanotube architectures and networks are transferred in PDMS matrix using casting process thereby creating highly organized carbon nanotube based flexible composite structures. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We will demonstrate its robustness under large stress conditions, under which the composite is found to retain its conducting nature. We will also demonstrate that these structures can be directly utilized as flexible field-emission devices. Our devices show some of the best field enhancement factors and turn-on electric fields reported so far.

scholarly journals Mechanical and Electroconductive Properties of Mono- and Bilayer Graphene–Carbon Nanotube Films

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 74 ◽  
Author(s):  
Michael Slepchenkov ◽  
Olga Glukhova
Keyword(s):  
Carbon Nanotube ◽  
Composite Film ◽  
Electrical Resistance ◽  
Composite Films ◽  
Bilayer Film ◽  
Vertical Force ◽  
Covalent Bonds ◽  
Local Stresses ◽  
Axial Stretching ◽  
Tube Distance

This article presents the results of a computer study of electrical conductivity and deformation behavior of new graphene–carbon nanotube (CNT) composite films under bending and stretching. Mono- and bilayer hybrid structures with CNTs (10,0) and (12,0) and an inter-tube distance of 10 and 12 hexagons were considered. It is revealed that elastic deformation is characteristic for mono- and bilayer composite films both in bending and stretching. It is found that, in the case of bending in a direction perpendicular to CNTs, the composite film takes the form of an arc, and, in the case of bending in a direction along CNTs, the composite film exhibits behavior that is characteristic of a beam subjected to bending deformation as a result of exposure to vertical force at its free end. It is shown that mono- and bilayer composite films are more resistant to axial stretching in the direction perpendicular to CNTs. The bilayer composite films with an inter-tube distance of 12 hexagons demonstrate the greatest resistance to stretching in a direction perpendicular to CNTs. It is established that the CNT diameter and the inter-tube distance significantly affect the strength limits of composite films under axial stretching in a direction along CNTs. The composite films with CNT (10,0) and an inter-tube distance of 12 hexagons exhibit the highest resistance to stretching in a direction along CNTs. The calculated distribution of local stresses of the atomic network of deformed mono- and bilayer composite films showed that the maximum stresses fall on atoms forming covalent bonds between graphene and CNT, regardless of the CNT diameter and inter-tube distance. The destruction of covalent bonds occurs at the stress of ~1.8 GPa. It is revealed that the electrical resistance of mono- and bilayer composite films decreases with increasing bending. At the same time, the electrical resistance of a bilayer film is 1.5–2 times less than that of a monolayer film. The lowest electrical resistance is observed for composite films with a CNT (12,0) of metallic conductivity.

Single Walled Carbon Nanotube Assisted Thermal Sensor

2014 ◽  
Vol 1752 ◽  
pp. 111-116
Author(s):  
S. Chandrasekar ◽  
K.S.V. Santhanam ◽  
Y. Yue ◽  
K. Kalaiazagan ◽  
L. Fuller
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Sodium Dodecyl Sulfate ◽  
Electrical Resistance ◽  
Methylene Chloride ◽  
Active Material ◽  
Sodium Dodecyl ◽  
Thermal Sensor ◽  
Single Walled Carbon ◽  
Dodecyl Sulfate

ABSTRACTA nano thermal sensor was made by depositing carbon nanotubes from a medium containing a) methylene chloride b)sodium dodecyl sulfate and c) Baytron-P (polymer) assisted sodium dodecyl sulfate. The nano thermal sensors showed d.c. electrical resistance as independent of temperature when the sensors were made by procedures (a) or (b). The electrical resistivity in both the situations has been independent of temperature. When the nanosensor is made with carbon nanotubes by assisted method (c), the d.c. electrical resistance decreased with temperature. The negative temperature coefficient (TCR) is manifested in the semiconducting property of the active material. The sensor behavior is reproducible and varies linearly with temperature. The nanosensor made by non assisted carbon nanotube showed zero TCR. This is probably the first instance of assisted thermal sensor made with single walled carbon nanotubes.

Electrical Resistance of Single-Wall Carbon Nanotubes with Determined Chiral Indices

2009 ◽  
Vol 1204 ◽  
Author(s):  
Letian Lin ◽  
Lu-Chang Qin ◽  
Sean Washburn ◽  
Scott Paulson
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Vapor Deposition ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Transmission Electron ◽  
Highly Sensitive

AbstractThe properties of a carbon nanotube (CNT), in particular a single-wall carbon nanotube (SWNT), are highly sensitive to the atomic structure of the nanotube described by its chirality (chiral indices). We have grown isolated SWNTs on a silicon substrate using chemical vapor deposition (CVD) and patterned sub-micron probes using electron beam lithography. The SWNT was exposed by etching the underlying substrate for transmission electron microscope (TEM) imaging and diffraction studies. For each individual SWNT, its electrical resistance was measured by the four-probe method at room temperature and the chiral indices of the same SWNT were determined by nano-beam electron diffraction. The contact resistances were reduced by annealing to typically 3-5 kΩ. We have measured the I-V curve and determined the chiral indices of each nanotube individually from four SWNTs selected randomly – two are metallic and two are semiconducting. We will present the electrical resistances in correlation with the carbon nanotube diameter as well as the band gap calculated from the determined chiral indices for the semiconducting carbon nanotubes. These experimental results are also discussed in connection with theoretical estimations.

Chemical structures and physical properties of vanadium oxide films modified by single-walled carbon nanotubes

2016 ◽  
Vol 18 (3) ◽  
pp. 1422-1428 ◽  
Author(s):  
Qiong He ◽  
Xiangdong Xu ◽  
Meng Wang ◽  
Minghui Sun ◽  
Yadong Jiang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Physical Properties ◽  
Vanadium Oxide ◽  
Composite Films ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Chemical Structures ◽  
Walled Carbon Nanotubes

A series of vanadium oxide (VOx)–single-walled carbon nanotube (SWCNT) composite films with different SWCNT concentrations were prepared and systematically investigated. The critical SWCNT concentrations for modification of VOx films were experimentally deduced.

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