scholarly journals Electrical Properties and Strain Sensing Mechanisms in Hybrid Graphene Nanoplatelet/Carbon Nanotube Nanocomposites

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5530
Author(s):  
Xoan F. Sánchez-Romate ◽  
Alberto Jiménez-Suárez ◽  
Mónica Campo ◽  
Alejandro Ureña ◽  
Silvia G. Prolongo
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Transport Mechanisms ◽  
Sonication Time ◽  
Strain Sensing ◽  
Electromechanical Properties ◽  
Exponential Behavior ◽  
Graphene Nanoplatelet ◽  
Low Viscosity ◽  
Nanofiller Content

Electrical and electromechanical properties of hybrid graphene nanoplatelet (GNP)/carbon nanotube (CNT)-reinforced composites were analyzed under two different sonication conditions. The electrical conductivity increases with increasing nanofiller content, while the optimum sonication time decreases in a low viscosity media. Therefore, for samples with a higher concentration of GNPs, an increase of sonication time of the hybrid GNP/CNT mixture generally leads to an enhancement of the electrical conductivity, up to values of 3 S/m. This means that the optimum sonication process to achieve the best performances is reached in the longest times. Strain sensing tests show a higher prevalence of GNPs at samples with a high GNP/CNT ratio, reaching gauge factors of around 10, with an exponential behavior of electrical resistance with applied strain, whereas samples with lower GNP/CNT ratio have a more linear response owing to a higher prevalence of CNT tunneling transport mechanisms, with gauge factors of around 3–4.

scholarly journals Highly Multifunctional GNP/Epoxy Nanocomposites: From Strain-Sensing to Joule Heating Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2431
Author(s):  
Xoan F. Sánchez-Romate ◽  
Alejandro Sans ◽  
Alberto Jiménez-Suárez ◽  
Mónica Campo ◽  
Alejandro Ureña ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Joule Heating ◽  
Dominant Role ◽  
Strain Sensors ◽  
Sonication Time ◽  
Strain Sensing ◽  
Strain Monitoring ◽  
Radar Chart ◽  
Nanofiller Content

A performance mapping of GNP/epoxy composites was developed according to their electromechanical and electrothermal properties for applications as strain sensors and Joule heaters. To achieve this purpose, a deep theoretical and experimental study of the thermal and electrical conductivity of nanocomposites has been carried out, determining the influence of both nanofiller content and sonication time. Concerning dispersion procedure, at lower contents, higher sonication times induce a decrease of thermal and electrical conductivity due to a more prevalent GNP breakage effect. However, at higher GNP contents, sonication time implies an enhancement of both electrical and thermal properties due to a prevalence of exfoliating mechanisms. Strain monitoring tests indicate that electrical sensitivity increases in an opposite way than electrical conductivity, due to a higher prevalence of tunneling mechanisms, with the 5 wt.% specimens being those with the best results. Moreover, Joule heating tests showed the dominant role of electrical mechanisms on the effectiveness of resistive heating, with the 8 wt.% GNP samples being those with the best capabilities. By taking the different functionalities into account, it can be concluded that 5 wt.% samples with 1 h sonication time are the most balanced for electrothermal applications, as shown in a radar chart.

Mechanical and Electrical Properties of Carbon Nanotube / Polydimethylsiloxane Composites Yarn

2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100 ◽  
Author(s):  
Wei Liu ◽  
Fujun Xu ◽  
Nianhua Zhu ◽  
Shuang Wang
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Strain Sensors ◽  
Electromechanical Properties ◽  
Average Strength ◽  
Mechanical And Electrical Properties ◽  
Carbon Nano Tube ◽  
Droplet Infiltration

Carbon nano tube (CNT) yarn is an axially aligned CNT assembly. It has great potential many applications. In this study, the mechanical and electrical properties of the aerogel-spun CNT yarns and CNT/Polydimethylsiloxane (PDMS) composite yarns were investigated. The CNT/PDMS yarn was fabricated by droplet infiltration of PDMS solution into the aerogel-spun CNT yarn. The mechanical properties of the CNT/PDMS yarns were significantly improved with an average strength of 837.29 MPa and modulus of 3.66 GPa, over 100% improvement compared to the original CNT yarns. The electrical conductivity of the CNT/PDMS yarn increased from 1636 S/cm to 3555 S/cm. The electromechanical properties of CNT/PDMS yarns demonstrated that such CNT yarn could be suitable for strain sensors.

Electromechanical strain sensing using polycarbonate-impregnated carbon nanotube–graphene nanoplatelet hybrid composite sheets

2013 ◽  
Vol 89 ◽  
pp. 1-9 ◽  
Author(s):  
Sang-Ha Hwang ◽  
Hyung Wook Park ◽  
Young-Bin Park ◽  
Moon-Kwang Um ◽  
Joon-Hyung Byun ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hybrid Composite ◽  
Strain Sensing ◽  
Graphene Nanoplatelet

Graphene nanoplatelet, multiwall carbon nanotube, and hybrid multiwall carbon nanotube–graphene nanoplatelet epoxy nanocomposites as strain sensing coatings

2021 ◽  
pp. 073168442199432
Author(s):  
Mario Bragaglia ◽  
Lorenzo Paleari ◽  
Francesca R Lamastra ◽  
Debora Puglia ◽  
Francesco Fabbrocino ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Residual Life ◽  
Mixed System ◽  
Gauge Factor ◽  
Multiwall Carbon Nanotube ◽  
Strain Sensing ◽  
Graphene Nanoplatelet ◽  
Glass Fiber Reinforced ◽  
Multiwall Carbon ◽  
Sensing Performance

Strain monitoring is of great interest in order to check components structural life, to prevent catastrophic failures, and, possibly, to predict residual life in case of unexpected events. In this study, strain sensing epoxy-based coatings containing carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and a mix of the two (MWCNT+GNP) have been produced, with the same initial electrical resistivity, and applied on glass fiber reinforced composites. Morphological, mechanical, and electrical tests have been then performed evaluating the resistance variation and the strain sensing performance of the sensors. A theoretical model to relate the resulting gauge factors to the different types of nanofillers has been applied. The results showed that all systems present a strain sensing performance with different gauge factors (and hence sensitivity) at low strain: GNP samples showed the highest gauge factor (10.3), MWCNT samples the lowest (1.5), and the mixed system lies in the middle (4.3). From analytical analysis, the value of initial distance among conductive particles was found to be 0.3 nm in the case of MWCNT and 1.2 nm for GNP, explaining why the gauge factors of the produced sensors are different.

scholarly journals Synthesis and Characterization of Multi-Walled Carbon Nanotube/Graphene Nanoplatelet Hybrid Film for Flexible Strain Sensors

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 786 ◽  
Author(s):  
JianRen Huang ◽  
Shiuh-Chuan Her ◽  
XiaoXiang Yang ◽  
MaNan Zhi
Keyword(s):  
Carbon Nanotube ◽  
Hybrid Film ◽  
Hall Effect Measurement ◽  
Applied Strain ◽  
Strain Sensitivity ◽  
Strain Sensing ◽  
Graphene Nanoplatelet ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotube ◽  
Triton X

Graphene nanoplatelet (GNP) and multi-walled carbon nanotube (MWCNT) hybrid films were prepared with the aid of surfactant Triton X-100 and sonication through a vacuum filtration process. The influence of GNP content ranging from 0 to 50 wt.% on the mechanical and electrical properties was investigated using the tensile test and Hall effect measurement, respectively. It showed that the tensile strength of the hybrid film is decreasing with the increase of the GNP content while the electrical conductivity exhibits an opposite trend. The effectiveness of the MWCNT/GNP hybrid film as a strain sensor is presented. The specimen is subjected to a flexural loading, and the electrical resistance measured by a two-point probe method is found to be function of applied strain. Experimental results demonstrate that there are two different linear strain-sensing stages (0–0.2% and 0.2–1%) in the resistance of the hybrid film with applied strain. The strain sensitivity is increasing with the increase of the GNP content. In addition, the repeatability and stability of the strain sensitivity of the hybrid film were conformed through the cyclic loading–unloading tests. The MWCNT/GNP hybrid film shows promising application for strain sensing.

scholarly journals Influence of Carbon Nanotube-Pretreatment on the Properties of Polydimethylsiloxane/Carbon Nanotube-Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1355
Author(s):  
Astrid Diekmann ◽  
Marvin C. V. Omelan ◽  
Ulrich Giese
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Mechanical Performance ◽  
Softening Effect ◽  
Electrical Percolation ◽  
Optimum Parameters ◽  
Lauryl Ether ◽  
Solvent Residues ◽  
Electrical Percolation Threshold ◽  
Filler Dispersion

Incorporating nanofillers into elastomers leads to composites with an enormous potential regarding their properties. Unfortunately, nanofillers tend to form agglomerates inhibiting adequate filler dispersion. Therefore, different carbon nanotube (CNT) pretreatment methods were analyzed in this study to enhance the filler dispersion in polydimethylsiloxane (PDMS)/CNT-composites. By pre-dispersing CNTs in solvents an increase in electrical conductivity could be observed within the sequence of tetrahydrofuran (THF) > acetone > chloroform. Optimization of the pre-dispersion step results in an AC conductivity of 3.2 × 10−4 S/cm at 1 Hz and 0.5 wt.% of CNTs and the electrical percolation threshold is decreased to 0.1 wt.% of CNTs. Optimum parameters imply the use of an ultrasonic finger for 60 min in THF. However, solvent residues cause a softening effect deteriorating the mechanical performance of these composites. Concerning the pretreatment of CNTs by physical functionalization, the use of surfactants (sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene lauryl ether (“Brij35”)) leads to no improvement, neither in electrical conductivity nor in mechanical properties. Chemical functionalization enhances the compatibility of PDMS and CNT but damages the carbon nanotubes due to the oxidation process so that the improvement in conductivity and reinforcement is superimposed by the CNT damage even for mild oxidation conditions.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

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