PIEZORESISTIVE PROPERTIES OF MULTI-WALLED CARBON NANOTUBE–POLY(DIMETHYLSILOXANE) COMPOSITES FOR LOW-PRESSURE-SENSING APPLICATIONS

Low-pressure-sensitive composites using multi-walled carbon nanotubes as a conductive filler and poly(dimethylsiloxane) as a polymer matrix have been fabricated, and their electrical and piezoresistive properties have been studied. A large aspect ratio of the MWCNTs was used to achieve good electrical properties of the composite, which led to a significant decrease in the percolation threshold and an increase in the electrical conductivity for very low MWCNT loadings. The piezoresistive properties of the composites at < 1.2 MPa were studied, which showed that the resistance–pressure sensitivity of the composites could be modulated by varying the MWCNT loading in the PDMS matrix.

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Multi-Walled Carbon Nanotubes-Based Sensors for Strain Sensing Applications

Sensors ◽

10.3390/s21041261 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1261 ◽

Cited By ~ 2

Author(s):

Anindya Nag ◽

Md. Eshrat E Alahi ◽

Subhas Chandra Mukhopadhyay ◽

Zhi Liu

Keyword(s):

Structural Changes ◽

Mechanical And Thermal Properties ◽

Strain Sensing ◽

Sensing Applications ◽

Multi Walled Carbon Nanotube ◽

Wide Range ◽

Multi Walled Carbon Nanotubes ◽

Conductive Nanomaterials ◽

Walled Carbon Nanotubes

The use of multi-walled carbon nanotube (MWCNT)-based sensors for strain–strain applications is showcased in this paper. Extensive use of MWCNTs has been done for the fabrication and implementation of flexible sensors due to their enhanced electrical, mechanical, and thermal properties. These nanotubes have been deployed both in pure and composite forms for obtaining highly efficient sensors in terms of sensitivity, robustness, and longevity. Among the wide range of applications that MWCNTs have been exploited for, strain-sensing has been one of the most popular ones due to the high mechanical flexibility of these carbon allotropes. The MWCNT-based sensors have been able to deduce a broad spectrum of macro- and micro-scaled tensions through structural changes. This paper highlights some of the well-approved conjugations of MWCNTs with different kinds of polymers and other conductive nanomaterials to form the electrodes of the strain sensors. It also underlines some of the measures that can be taken in the future to improve the quality of these MWCNT-based sensors for strain-related applications.

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Characterization and modeling of the effective electrical conductivity of a carbon nanotube/polymer composite containing chain-structured ferromagnetic particles

Journal of Composite Materials ◽

10.1177/0021998316644846 ◽

2016 ◽

Vol 51 (2) ◽

pp. 171-178 ◽

Cited By ~ 9

Author(s):

Sung-Hwan Jang ◽

Huiming Yin

Keyword(s):

Electrical Conductivity ◽

Carbon Nanotube ◽

Chain Model ◽

Sensing Applications ◽

Effective Electrical Conductivity ◽

Multi Walled Carbon Nanotube ◽

The Matrix ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Ferromagnetic Particles

The effective electrical conductivity of multi-walled carbon nanotube/polydimethylsiloxane composites with chain-structured ferromagnetic particles has been investigated by experiments and micromechanics-based modeling. A multi-scale modeling approach is used to consider different size of fillers of multi-walled carbon nanotubes and particles as well as their distribution in the matrix. At nanoscale, for multi-walled carbon nanotube/polydimethylsiloxane composite, eight-chain model and influence of waviness of multi-walled carbon nanotube are considered to render an effective electrical conductivity. At microscale, ferromagnetic particles are aligned in the matrix made of the multi-walled carbon nanotube/polydimethylsiloxane composite, and an analytical model is established based on representative volume element. The influence of inter-particle distance is evaluated. The proposed analytic results agree well with the experimental results. The present model can be a useful tool for design and analysis of these composites for sensing applications considering their percolation threshold and overall electrical conductivity.

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Fabrication of carbon nanotube-reinforced mortar specimens: evaluation of mechanical and pressure-sensitive properties

MATEC Web of Conferences ◽

10.1051/matecconf/201818801019 ◽

2018 ◽

Vol 188 ◽

pp. 01019 ◽

Cited By ~ 3

Author(s):

Evangelia K. Karaxi ◽

Irene A. Kanellopoulou ◽

Anna Karatza ◽

Ioannis A. Kartsonakis ◽

Costas A. Charitidis

Keyword(s):

Cementitious Composites ◽

Mixing Process ◽

Mechanical And Electrical Properties ◽

Pressure Sensitive ◽

Polar Media ◽

Significant Research ◽

Multi Walled Carbon Nanotubes ◽

Carbon Based Nanomaterials ◽

Walled Carbon Nanotubes ◽

Carbon Based

Carbon-based nanomaterials are promising reinforcing elements for the development of “smart” self-sensing cementitious composites due to their exceptional mechanical and electrical properties. Significant research efforts have been committed on the synthesis of cement-based composite materials reinforced with carbonaceous nanostructures, covering every aspect of the production process (type of nanomaterial, mixing process, electrode type, measurement methods etc.). In this study, the aim is to develop a well-defined repeatable procedure for the fabrication as well as the evaluation of pressure-sensitive properties of intrinsically self-sensing cementitious composites incorporating carbon- based nanomaterials. Highly functionalized multi-walled carbon nanotubes with increased dispersibility in polar media were used in the development of advanced reinforced mortar specimens which increased their mechanical properties and provided repeatable pressure-sensitive properties.

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Multi-Walled Carbon Nanotubes as Electrocatalyst Supports for H2O2 Reduction Reaction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.860-863.831 ◽

2013 ◽

Vol 860-863 ◽

pp. 831-834

Author(s):

Dan Zheng ◽

Ting Fang Yang ◽

Zhang Fei Guo

Keyword(s):

Cyclic Voltammetry Curve ◽

Chemical Reduction ◽

Reduction Reaction ◽

Carbon Substrate ◽

Acid Media ◽

Multi Walled Carbon Nanotube ◽

Multi Walled Carbon Nanotubes ◽

Current Densities ◽

Reaction Activation Energy ◽

Walled Carbon Nanotubes

This work studies the use of Multi-walled carbon nanotube (MWCNT) as catalyst supports for H2O2 electro-reduction in acid media. Using impregnation-chemical reduction method, we prepared Pt-Ag/CNTs, Pt-Co/CNTs, Pt-Ag/C and Pt-Co/C nanocatalysts. Four catalysts were analyzed by XRD and TEM. Their electrochemical performance was studied via cyclic voltammetry curve. The results show that: the nanoparticles have a better dispersion on CNTs substrate than on XC-72 carbon substrate. Comparing with Pt-Ag and Pt-Co on XC-72 carbon substrate, the H2O2 reduction reaction activation energy of catalysts on CNTs substrate is bigger, and the peak current densities of catalysts on CNTs substrate are larger than that on XC-72 carbon.

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Hydrophobic Coating of Multi-Walled Carbon Nanotubes by Using a HMDSO Glow Plasma under Low Pressure

Journal of the Korean Physical Society ◽

10.3938/jkps.53.641 ◽

2008 ◽

Vol 53 (2) ◽

pp. 641-645 ◽

Cited By ~ 4

Author(s):

Sung Yoon Jo ◽

Soon Cheon Cho ◽

Kyung Ha Lee ◽

Han Sup Uhm

Keyword(s):

Carbon Nanotubes ◽

Low Pressure ◽

Hydrophobic Coating ◽

Multi Walled Carbon Nanotubes ◽

Glow Plasma ◽

Walled Carbon Nanotubes

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Highly sensitive compression sensors using three-dimensional printed polydimethylsiloxane/carbon nanotube nanocomposites

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x19835953 ◽

2019 ◽

Vol 30 (8) ◽

pp. 1216-1224 ◽

Cited By ~ 11

Author(s):

Mohammad Charara ◽

Mohammad Abshirini ◽

Mrinal C Saha ◽

M Cengiz Altan ◽

Yingtao Liu

Keyword(s):

Carbon Nanotubes ◽

Electron Microscope ◽

Carbon Nanotube ◽

Scanning Electron Microscope ◽

Three Dimensional ◽

Multi Walled Carbon Nanotube ◽

Highly Sensitive ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Scanning Electron

This article presents three-dimensional printed and highly sensitive polydimethylsiloxane/multi-walled carbon nanotube sensors for compressive strain and pressure measurements. An electrically conductive polydimethylsiloxane/multi-walled carbon nanotube nanocomposite is developed to three-dimensional print compression sensors in a freestanding and layer-by-layer manner. The dispersion of multi-walled carbon nanotubes in polydimethylsiloxane allows the uncured nanocomposite to stand freely without any support throughout the printing process. The cross section of the compression sensors is examined under scanning electron microscope to identify the microstructure of nanocomposites, revealing good dispersion of multi-walled carbon nanotubes within the polydimethylsiloxane matrix. The sensor’s sensitivity was characterized under cyclic compression loading at various max strains, showing an especially high sensitivity at lower strains. The sensing capability of the three-dimensional printed nanocomposites shows minimum variation at various applied strain rates, indicating its versatile potential in a wide range of applications. Cyclic tests under compressive loading for over 8 h demonstrate that the long-term sensing performance is consistent. Finally, in situ micromechanical compressive tests under scanning electron microscope validated the sensor’s piezoresistive mechanism, showing the rearrangement, reorientation, and bending of the multi-walled carbon nanotubes under compressive loads, were the main reasons that lead to the piezoresistive sensing capabilities in the three-dimensional printed nanocomposites.

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The Importance of Evaluating the Lot-to-Lot Batch Consistency of Commercial Multi-Walled Carbon Nanotube Products

Nanomaterials ◽

10.3390/nano10101930 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1930

Author(s):

Mai T. Huynh ◽

Jean Francois Veyan ◽

Hong Pham ◽

Raina Rahman ◽

Samad Yousuf ◽

...

Keyword(s):

Physicochemical Properties ◽

Defect Density ◽

Physicochemical Characterization ◽

Biological Response ◽

Raw 264.7 Cells ◽

Raw 264.7 ◽

Multi Walled Carbon Nanotube ◽

Multi Walled Carbon Nanotubes ◽

Pristine Mwnts ◽

Walled Carbon Nanotubes

The biological response of multi-walled carbon nanotubes (MWNTs) is related to their physicochemical properties and a thorough MWNT characterization should accompany an assessment of their biological activity, including their potential toxicity. Beyond characterizing the physicochemical properties of MWNTs from different sources or manufacturers, it is also important to characterize different production lots of the same MWNT product from the same vendor (i.e., lot-to-lot batch consistency). Herein, we present a comprehensive physicochemical characterization of two lots of commercial pristine MWNTs (pMWNTs) and carboxylated MWNTs (cMWNTs) used to study the response of mammalian macrophages to MWNTs. There were many similarities between the physicochemical properties of the two lots of cMWNTs and neither significantly diminished the 24-h proliferation of RAW 264.7 macrophages up to the highest concentration tested (200 μg cMWNTs/mL). Conversely, several physicochemical properties of the two lots of pMWNTs were different; notably, the newer lot of pMWNTs displayed less oxidative stability, a higher defect density, and a smaller amount of surface oxygen species relative to the original lot. Furthermore, a 72-h half maximal inhibitory concentration (IC-50) of ~90 µg pMWNTs/mL was determined for RAW 264.7 cells with the new lot of pMWNTs. These results demonstrate that subtle physicochemical differences can lead to significantly dissimilar cellular responses, and that production-lot consistency must be considered when assessing the toxicity of MWNTs.

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Self-assembly fabrication of a graphene/multi-walled carbon nanotube hybrid material for suppressing potential heat radiation and toxic effluent

RSC Advances ◽

10.1039/c5ra19227g ◽

2015 ◽

Vol 5 (125) ◽

pp. 103365-103372 ◽

Cited By ~ 1

Author(s):

Lei Liu ◽

Dong Wang ◽

Yuan Hu

Keyword(s):

Carbon Nanotubes ◽

Aqueous Solution ◽

Graphene Oxide ◽

Carbon Nanotube ◽

Hybrid Material ◽

Self Assembly ◽

Heat Radiation ◽

Multi Walled Carbon Nanotube ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

Negative graphene oxide was combined with positive chitosan-modified multi-walled carbon nanotubes in aqueous solution and then thermally reduced to fabricate a multi-walled carbon nanotube/graphene (MWCNT/G) hybrid material.

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Comparative carcinogenicity study of a thick, straight-type and a thin, tangled-type multi-walled carbon nanotube administered by intra-tracheal instillation in the rat

Particle and Fibre Toxicology ◽

10.1186/s12989-020-00382-y ◽

2020 ◽

Vol 17 (1) ◽

Cited By ~ 1

Author(s):

Dina Mourad Saleh ◽

William T. Alexander ◽

Takamasa Numano ◽

Omnia Hosny Mohamed Ahmed ◽

Sivagami Gunasekaran ◽

...

Keyword(s):

Peritoneal Cavity ◽

Initial Study ◽

Pleural Mesothelioma ◽

Rat Lung ◽

Carcinogenicity Study ◽

Carcinogenic Potential ◽

Multi Walled Carbon Nanotube ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Observation Period

Abstract Background Multi-walled carbon nanotubes can be divided into two general subtypes: tangled and straight. MWCNT-N (60 nm in diameter) and MWCNT-7 (80–90 nm in diameter) are straight-type MWCNTs, and similarly to asbestos, both are carcinogenic to the lung and pleura when administered to rats via the airway. Injection of straight-type MWCNTs into the peritoneal cavity also induces the development of mesothelioma, however, injection of tangled-type MWCNTs into the peritoneal cavity does not induce carcinogenesis. To investigate these effects in the lung we conducted a 2-year comparative study of the potential carcinogenicities of a straight-type MWCNT, MWCNT-A (approximately 150 nm in diameter), and a tangled-type MWCNT, MWCNT-B (7.4 nm in diameter) after administration into the rat lung. Crocidolite asbestos was used as the reference material, and rats administered vehicle were used as the controls. Test materials were administered by intra-Tracheal Intra-Pulmonary Spraying (TIPS) once a week over a 7 week period (8 administrations from day 1 to day 50), followed by a 2-year observation period without further treatment. Rats were administered total doses of 0.5 or 1.0 mg MWCNT-A and MWCNT-B or 1.0 mg asbestos. Results There was no difference in survival between any of the groups. The rats administered MWCNT-A or asbestos did not have a significant increase in bronchiolo-alveolar hyperplasia or tumors in the lung. However, the rats administered MWCNT-B did have significantly elevated incidences of bronchiolo-alveolar hyperplasia and tumors in the lung: the incidence of bronchiolo-alveolar hyperplasia was 0/20, 6/20, and 9/20 in the vehicle, 0.5 mg MWCNT-B, and 1.0 mg MWCNT-B groups, respectively, and the incidence of adenoma and adenocarcinoma combined was 1/19, 5/20, and 7/20 in the vehicle, 0.5 mg MWCNT-B, and 1.0 mg MWCNT-B groups, respectively. Malignant pleural mesothelioma was not induced in any of the groups. Conclusions The results of this initial study indicate that tangled-type MWCNT-B is carcinogenic to the rat lung when administered via the airway, and that straight-type MWCNT-A did not have higher carcinogenic potential in the rat lung than tangled-type MWCNT-B.

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