Multiwalled carbon nanotube film for strain sensing (original) (raw)
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Strain sensing using a multiwalled carbon nanotube film
2009
Abstract The effectiveness of multiwalled carbon nanotubes (MWCNTs) as strain sensors is investigated. The key contribution of this paper is the study of real-time strain response at the macroscale of MWCNT film under tensile load. In addition, real-time voltage change as a function of temperature is examined. MWCNT films attached to a brass specimen by epoxy using vacuum bonding have been studied.
An investigative study on application of carbon nanotubes for strain sensing
Nanosystems: Physics, Chemistry, Mathematics, 2016
Traditional strain sensors, such as metal foil gauges, can measure the strains only on the structural surface in designated directions and locations. Hence, there is a need to develop new types of strain sensors which can function on both the micro-and macro-scale, either on the surface or embedded in the structure, and able to behave as multifunctional materials. Owing to its outstanding electrical and mechanical properties carbon nanotubes (CNTs) can be used as strain sensing material. A film (Bucky paper/CNT network) made from multiwalled carbon nanotubes by use of solvent/surfactant and vacuum filtration method is used as strain sensor. The paper discusses the experimental work involving preparation of CNT film sensor specimen, its application on aluminum and brass strips along with conventional foil gauge and subjecting the metal strips to axial loading to measure gauge factor. It was found that CNT film strain sensor shows linear relationship between change in resistance and strain. Furthermore, the gauge factor increases as the film aspect ratio increases, and for the same aspect ratio, a higher gauge factor was observed for brass than aluminum.
Nanotube film based on single-wall carbon nanotubes for strain sensing
2004
Abstract Carbon nanotubes change their electronic properties when subjected to strains. In this study, the strain sensing characteristic of carbon nanotubes is used to develop a carbon nanotube film sensor that can be used for strain sensing on the macro scale. The carbon nanotube film is isotropic due to randomly oriented bundles of single-wall carbon nanotubes (SWCNTs). Using experimental results it is shown that there is a nearly linear change in voltage across the film when it is subjected to tensile and compressive stresses.
Conformable Single-Walled Carbon Nanotube Thin Film Strain Sensors for Structural Monitoring
The need for monitoring the condition of large-scale infrastructure systems has motivated a recent interest in novel sensor technologies for structural health monitoring. To provide the structural health monitoring system with data that captures local structural behavior, the measurement of component-level strain is valuable. Although current foil-based strain gauges are capable of measuring strain deformations, their low sensitivity and drift properties render them poorly suited for long-term field installation. In this study, a novel strain sensor is presented for the purpose of structural monitoring. The presented strain sensor is based on a layer-bylayer chemical film deposition technique to produce a nanocomposite consisting of single-walled carbon nanotubes (SWNT) and polyelectrolytes (PE). Engineered at the molecular-level, the performance of the thin film strain sensor can be optimized for structural monitoring applications, including attainment of high gauge factors. To validate the sensitivity and precision of the conformable SWNT-PE thin film strain sensor, this study undertakes a series of laboratory experiments where thin films are loaded under monotonic and cyclic load patterns.
Flexible Carbon Nanotube Films for High Performance Strain Sensors
Sensors, 2014
Compared with traditional conductive fillers, carbon nanotubes (CNTs) have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film
A carbon nanotube strain sensor for structural health monitoring
Smart Materials and Structures, 2006
A carbon nanotube polymer material was used to form a piezoresistive strain sensor for structural health monitoring applications. The polymer improves the interfacial bonding between the nanotubes. Previous single walled carbon nanotube buckypaper sensors produced distorted strain measurements because the van der Waals attraction force allowed axial slipping of the smooth surfaces of the nanotubes. The polymer sensor uses larger multi-walled carbon nanotubes which improve the strain transfer, repeatability and linearity of the sensor. An electrical model of the nanotube strain sensor was derived based on electrochemical impedance spectroscopy and strain testing. The model is useful for designing nanotube sensor systems. A biomimetic artificial neuron was developed by extending the length of the sensor. The neuron is a long continuous strain sensor that has a low cost, is simple to install and is lightweight. The neuron has a low bandwidth and adequate strain sensitivity. The neuron sensor is particularly useful for detecting large strains and cracking, and can reduce the number of channels of data acquisition needed for the health monitoring of large structures.
Application of multi-walled carbon nanotube film strain gauge on metallic surface
2012
In this work we investigated the possibility to use CNT film strain gauge on the metallic surface. Brass cantilever was used to investigate the tensile and compressive strain sensing property of MWCNT films. Two types of isolation layer were used between MWCNT film and brass cantilever, ink jet film and aerosol varnish. From the measurements we found higher gauge factor can be obtained by using aerosol varnish as isolation layer due to a better transfer of loading. CNT films produced by two types of MWCNTs have different conductivity and gauge factor. By choosing the suitable CNTs, compromise should thus be made between conductivity and reproducibility as well as the sensitivity depending on the different applications. MWCNT-polymer (Polyethylene oxide, PEO) composites with different MWCNT weight fractions were also produced to obtain higher and tailored gauge factor. Higher gauge factor of 10 can be achieved for MWCNT-PEO composite film with 2.5wt% MWCNTs. Tailored gauge factor can be achieved by changing the MWCNT concentration.
Sensors (Basel, Switzerland), 2015
This paper describes the development of an innovative carbon nanotube-based non-woven composite sensor that can be tailored for strain sensing properties and potentially offers a reliable and cost-effective sensing option for structural health monitoring (SHM). This novel strain sensor is fabricated using a readily scalable process of coating Carbon nanotubes (CNT) onto a nonwoven carrier fabric to form an electrically-isotropic conductive network. Epoxy is then infused into the CNT-modified fabric to form a free-standing nanocomposite strain sensor. By measuring the changes in the electrical properties of the sensing composite the deformation can be measured in real-time. The sensors are repeatable and linear up to 0.4% strain. Highest elastic strain gage factors of 1.9 and 4.0 have been achieved in the longitudinal and transverse direction, respectively. Although the longitudinal gage factor of the newly formed nanocomposite sensor is close to some metallic foil strain gages, the ...
Aligned carbon nanotube based sensors for strain sensing applications
Sensors and Actuators A: Physical, 2019
This paper presents an aligned carbon nanotube (CNT)-based strain sensor. Vertical aligned carbon nanotubes (VA-CNT), synthesized by chemical vapour deposition (CVD), were knocked down onto polymeric films, in order to obtain a thin 10 × 10 × 0.05 mm CNT patch. Different polymeric substrates, ADEXepoxy, polyethylene terephthalate (PET) and polyimide (PI) were used. The samples' morphology before and after the knock down process, specifically their alignment, was observed by scanning electron microscopy (SEM). The good quality of the synthesized VA-CNT was assessed by Raman spectroscopy. Furthermore, transmission electron microscopy (TEM) analysis was carried out to determine the average wall number and diameters (inner and outer) of the VA-CNT. A MATLAB software with an adapted Van der Pauw method for anisotropic conductors was developed to determine the electric properties of the obtained samples, which were strained in the transverse (X) and parallel (Y) directions with respect to the CNT alignment. The electric anisotropy, defined as electric resistance ratio between obtained measurements along the X (R xx) and Y (R yy)-axes, decreases with deformation increment when the sample was strained in the Y-direction, while it increases when strained in the X-direction. Moreover, the obtained Gauge factor values showed a much sensitive response to deformation, i.e., approximately 47% increase in GF values, when the samples are strained transversely to CNT alignment. These results showed that the piezoresistive CNT/polymeric based sensor produced is suitable for strain sensing applications.
Flexural strain sensing using carbon nanotube film
2004
Abstract: Strain sensing characteristic of carbon nanotubes has been established in the past at nanoscale. In this study, it is shown that the carbon nanotube film sensors, made up of randomly oriented carbon nanotubes, can be used as strain sensors at macro level. A nearly linear trend between the change in voltage, measured using a movable four point probe, and strains, measured using conventional electrical strain gage, indicates the potential of such carbon nanotube films for measuring flexural strains at macro level.