scholarly journals Studying of a sensitive material based on Ecoflex and CNTs for flexible strain sensors

2021 ◽  
Vol 2086 (1) ◽  
pp. 012010
Author(s):  
N A Demidenko ◽  
A V Kuksin ◽  
E S Davydova ◽  
V A Zaborova ◽  
L P Ichkitidze ◽  
...  

Abstract Nowadays there is a great need for the development of flexible strain sensors that can register human body’s movements. In the field of wearable and smart electronics such sensors are actively being developed. Resistive-type flexible sensors are the easiest to manufacture. Their mechanism of sensitivity to deformations is based on a change in electrical resistance during deformations. In this work, we have developed the functional material for strain sensor with high tensile properties, strength and electrical conductivity. This material based on a matrix of silicone elastomer and a multi-walled carbon nanotubes (MCNTs) filler. The material showed a high elongation of 950 % with a tensile strength of 1.437 MPa. The manufacturing process included laser structuring of MCNTs to form an electrically conductive network. The linear gauge factor was 3.4, and the angular gauge factor was 0.26.

2021 ◽  
Vol 6 (1) ◽  
pp. 23
Author(s):  
Levan P. Ichkitidze ◽  
Alexander Yu. Gerasimenko ◽  
Dmitry V. Telyshev ◽  
Eugeny P. Kitsyuk ◽  
Vladimir A. Petukhov ◽  
...  

We investigated a prototype of a strain sensor based on the layers of a bionanomaterial containing bovine serum albumin (BSA matrix) and multi-walled carbon nanotubes (MWCNT filler). The aqueous dispersion of 25 wt.% BSA/0.3 wt.% MWCNT was applied by screen printing onto flexible polyethylene terephthalate substrates. After drying the layers by laser irradiation (~970 nm), various parameters of the layers were controlled, i.e., resistance R, bending angle θ, number of cycles n, and measurement time. One measurement cycle corresponded to a change within the range θ = ±150°. The layers of the BSA/MWCNT bionanomaterial had dimensions of (15 ÷ 20) mm × (8 ÷ 10) mm × (0.5 ÷ 1. 5) µm. The dependences of resistance R on the bending angle θ were similar for all layers at θ = ±30, and the R(θ) curves represented approximate linear dependences (with an error of ≤ 10%); beyond this range, the dependences became nonlinear. The following quantitative values were obtained for the investigated strain sensor: specific conductivity ~1 ÷ 10 S/m, linear strain sensitivity ~160, and bending sensitivity 1.0 ÷ 1.5%/°. These results are high. The examined layers of the bionanomaterial BSA/MWCNT as a strain sensor are of particular interest for medical practice. In particular, strain sensors can be implemented by applying a water dispersion of nanomaterials to human skin using a 3D printer for monitoring movements (arms and blinking) and the detection of signs of pathology (dysphagia, respiratory diseases, angina, etc.).


Author(s):  
V. S. Yagubov ◽  
A. V. Shchegolkov

The review of modern approaches to the development of electric heating materials makes it possible to conclude that the studies of electrically conductive composites are based on using elastomers modified with nanoscale carbon materials. In the manufacturing of electric heaters, temperature self-regulation is the main property that increases their characteristics. However, researchers engaged in studying such heaters, face difficulties associated with the magnitude of supply voltage and power. In this regard, the tasks of the present work were as follows: to study the modifier characteristics for nanomodified heaters, and to select a modifier that is best dispersed in the elastomer, which will ensure the maximum magnitude of the supply voltage and the high value of the specific power of the heater. To develop an electric heater, silicone rubber modified with carbon nanotubes was used as an elastomer. The method for manufacturing the heating element nanomodified material was described. Multi-walled carbon nanotubes synthesized through the CVD method were employed as an electrically conductive modifier. Before modifying the elastomer, the carbon nanotubes were processed in a mill at a rotational speed of working blades of 25,000 rpm. Then, the nanotubes were thermally treated in a furnace until the temperature of 110 °C was reached. After that, the nanotubes and the elastomer were mixed using a BRABENDER mixer, followed by pressing and obtaining plates of the electric heating material. To ensure contact between the heater and the power source, aluminum foil, inserted into the punches before pressing, was used. The electrical conductivity of the elastic heater nanomodified material was studied using a setup (facility) constructed especially for that purpose. Based on the results obtained, a conclusion can be made on the expediency of using different multi-walled carbon nanotubes as elastomer modifiers, which form electrically conductive networks inside the elastomer and are capable of releasing heat when connected to an electrical voltage source. Employing a non-contact method of measuring the temperature field on the electric heater surface, thermograms were recorded. It was found that the temperature field is uniformly distributed on the heater surface and is stabilized at a certain time after achieving a thermal balance with the environment. From the data obtained, it can be concluded that the heating element connected to an alternating current network with a voltage of 220 V is efficient.


2018 ◽  
Vol 52 (24) ◽  
pp. 3325-3340 ◽  
Author(s):  
Doo-Yeol Yoo ◽  
Ilhwan You ◽  
Hyunchul Youn ◽  
Seung-Jung Lee

This study investigates the effect of nanomaterials on the piezoresistive sensing capacity of cement-based composites. Three different nanomaterials—multi-walled carbon nanotubes, graphite nanofibers, and graphene oxide—were considered along with a plain mortar, and a cyclic compressive test was performed. Based on a preliminary test, the optimum flowability was determined to be 150 mm in terms of fiber dispersion. The electrical resistivity of the composites substantially decreased by incorporating 1 wt% multi-walled carbon nanotubes, but only slightly decreased by including 1 wt% graphite nanofibers and graphene oxide. This indicates that the use of multi-walled carbon nanotubes is most effective in improving the conductivity of the composites compared to the use of graphite nanofibers and graphene oxide. The fractional change in resistivity of the composites with nanomaterials exhibited similar behavior to that of the cyclic compressive load, but partial reversibility in fractional change in resistivity was obtained beyond 60% of the peak load. A linear relationship between the fractional change in resistivity and cyclic compression strain (up to 1500 με) was observed in the composites with multi-walled carbon nanotubes, and the gauge factor was found to be 166.6. It is concluded that cement-based composites with 1 wt% multi-walled carbon nanotubes can be used as piezoresistive sensors for monitoring the stress/strain generated in concrete structures.


This work is devoted to the study of the effect of carbon nanotubes functionalization on the electrical conductivity of composite materials based on them. Carbon nanotubes were functionalized by treatment in nitric acid and isopropyl alcohol. Changes in the morphology of multi-walled carbon nanotubes during liquid-phase functionalization were investigated using Auger-electron microscopy. Samples of composite material on the basis of initial and functionalized carbon nanotubes and epoxy resin were prepared and the concentration dependence of electrical conductivity using the four-probe method was studied. The study reveals the effect of functionalization in various solutions on the electrophysical properties of the obtained carbon nanotubes/epoxy composites.


Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1885 ◽  
Author(s):  
Macedo Lima ◽  
Orozco ◽  
Picchioni ◽  
Moreno-Villoslada ◽  
Pucci ◽  
...  

In this work, we prepared electrically conductive self-healing nanocomposites. The material consists of multi-walled carbon nanotubes (MWCNT) that are dispersed into thermally reversible crosslinked polyketones. The reversible nature is based on both covalent (Diels-Alder) and non-covalent (hydrogen bonding) interactions. The design allowed for us to tune the thermomechanical properties of the system by changing the fractions of filler, and diene-dienophile and hydroxyl groups. The nanocomposites show up to 1 × 104 S/m electrical conductivity, reaching temperatures between 120 and 150 °C under 20–50 V. The self-healing effect, induced by electricity was qualitatively demonstrated as microcracks were repaired. As pointed out by electron microscopy, samples that were already healed by electricity showed a better dispersion of MWCNT within the polymer. These features point toward prolonging the service life of polymer nanocomposites, improving the product performance, making it effectively stronger and more reliable.


2015 ◽  
Vol 825-826 ◽  
pp. 67-74
Author(s):  
Kristin Trommer ◽  
Bernd Morgenstern ◽  
Carina Petzold

The electrically induced heating of textile composite materials is already applied in the clothing and outdoor use. However, making thin, flexible and washable heating layers remains a challenge. Based on various polymers thin electrically heatable polymer sheets were developed using multi-walled carbon nanotubes as electrically conductive fillers in silicone, polyurethane as well as polyvinylchloride. To prepare the membranes a knife coating process was applied. The viscosity of the polymer masses, the particle alignment, the percolation as well as the electrically and heating properties of the membranes were investigated.


2018 ◽  
Vol 25 (6) ◽  
pp. 1177-1186 ◽  
Author(s):  
Radwan Dweiri ◽  
Hendra Suherman ◽  
Abu Bakar Sulong ◽  
Jafar F. Al-Sharab

AbstractThis paper investigates the structure-property-processing correlations of electrically conductive polypropylene (PP) nanocomposites. The process parameters and fabrication techniques of PP-based composite materials were studied. Various structures of carbon allotrope-based materials, including synthetic graphite (SG), exfoliated graphene nanoplatelets (xGnP), multi-walled carbon nanotubes (MWCNTs) and carbon black (CB), were used to fabricate the PP-based nanocomposites. The nanocomposites were prepared by either direct melt mixing using an internal mixer or by ball milling of components before the melt mixing process. The electrical and flexural properties were measured. In order to understand the conductivity behavior, both in-plane and through-plane electrical conductivities were measured. The results showed that the incorporation of the xGnP into PP/60 wt.% SG composites resulted in a slight increase of the in-plane conductivities and had a minimal effect on the through-plane conductivities. The addition of MWCNTs and CB to the PP/SG/xGnP composites had a significant effect on the electrical properties and was more pronounced in the case of MWCNTs. The flexural properties of all samples were much lower than those of pure PP. The interface between the filler and the PP matrix and the morphology of the composite materials were observed from the fracture surfaces of the composites using scanning electron microscopy (SEM). In addition, SEM was employed to observe adhesion, microstructural homogeneity, orientation of the xGnP platelets and agglomeration in the composites.


2013 ◽  
Vol 341-342 ◽  
pp. 175-178
Author(s):  
Fan Zhang ◽  
Shu Hua Qi ◽  
Yi Zhang

In this paper, purified multi-walled carbon nanotubes (MWNTs) were obtained by acid treatment and oxidation treatment using the crude MWNTs, then purified MWNTs were filled into acrylate pressure-sensitive adhesive (PSA) to produce electrically conductive adhesives (ECAs). XRD and TEM results showed that the impurities were greatly eliminated after purification treatment. The electrical conductivity of the ECAs increased gradually as the content of the purified MWNTs increased. When the content of the purified MWNTs is 4.0vol%, the properties of ECAs are optimum.


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