Self-Sensing Carbon Nanotube Composites Exposed to Glass Transition Temperature

Jang, Sung-Hwan; Li, Long-yuan

doi:10.3390/ma13020259

Cited by 15 publications

(7 citation statements)

References 28 publications

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“…A dramatic increase in electrical conductivity was observed when the concentration of CNTs increased from 0.25 wt.% to 1.0 wt.%. This behavior has been attributed to the occurrence of a percolation threshold [ 21 , 22 , 23 , 24 ]. In this study the percolation threshold, i.e., the minimum CNT concentration in the matrix after which no significant change in the electrical conductivity is observed, occurred at around 0.63 wt.% CNTs.…”

Section: Resultsmentioning

confidence: 99%

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

et al. 2022

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In the construction and machinery industry, heat is a major factor causing damage and destruction. The safety and efficiency of most machines and structures are greatly affected by temperature, and temperature management and control are essential. In this study, a carbon nanotube (CNT) based temperature sensing coating that can be applied to machines and structures having various structural types was fabricated, and characteristics analysis and temperature sensing performance were evaluated. The surface coating, which detects temperature through resistance change is made of a nanocomposite composed of carbon nanotubes (CNT) and epoxy (EP). We investigated the electrical properties by CNT concentration and temperature sensing performance of CNT/EP coating against static and cyclic temperatures. In addition, the applicability of the CNT/EP coating was investigated through a partially heating and cooling experiment. As a result of the experiment, the CNT/EP coating showed higher electrical conductivity as the CNT concentration increased. In addition, the CNT/EP coating exhibits high sensing performance in the high and sub−zero temperature ranges with a negative temperature coefficient of resistance. Therefore, the proposed CNT/EP coatings are promising for use as multi-functional coating materials for the detection of high and freezing temperatures.

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Section: Resultsmentioning

confidence: 99%

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

et al. 2022

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“…The smart skin was fabricated by uniformly dispersing CNTs within a PU matrix, employing the same methodology as previous studies [29][30][31], as illustrated in Figure 2. Approximately 50 mL of acetone was used as a dispersing agent to dissolve the high-viscosity PU resin, facilitating the high-quality dispersion of CNTs.…”

Section: Fabrication Proceduresmentioning

confidence: 99%

Crack Detection of Reinforced Concrete Structure Using Smart Skin

Jung,

Jang

2024

Nanomaterials

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The availability of carbon nanotube (CNT)-based polymer composites allows the development of surface-attached self-sensing crack sensors for the structural health monitoring of reinforced concrete (RC) structures. These sensors are fabricated by integrating CNTs as conductive fillers into polymer matrices such as polyurethane (PU) and can be applied by coating on RC structures before the composite hardens. The principle of crack detection is based on the electrical change characteristics of the CNT-based polymer composites when subjected to a tensile load. In this study, the electrical conductivity and electro-mechanical/environmental characterization of smart skin fabricated with various CNT concentrations were investigated. This was performed to derive the tensile strain sensitivity of the smart skin according to different CNT contents and to verify their environmental impact. The optimal CNT concentration for the crack detection sensor was determined to be 5 wt% CNT. The smart skin was applied to an RC structure to validate its effectiveness as a crack detection sensor. It successfully detected and monitored crack formation and growth in the structure. During repeated cycles of crack width variations, the smart skin also demonstrated excellent reproducibility and electrical stability in response to the progressive occurrence of cracks, thereby reinforcing the reliability of the crack detection sensor. Overall, the presented results describe the crack detection characteristics of smart skin and demonstrate its potential as a structural health monitoring (SHM) sensor.

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“…5,6 These materials are conductive polymer composites (CPCs) that exhibit a sharp increase in electrical resistivity as temperature rises, resulting from the mismatch in thermal expansion coefficient between the polymer matrix and the filler. 7,8 However, a significant challenge in preparing these stimulusresponsive materials with a PTC effect lies in the poor compatibility between the inorganic conductive filler and the polymer matrix.…”

Section: ■ Introductionmentioning

confidence: 99%

“…They possess the ability to undergo changes in physical or chemical properties in response to external stimuli . A particularly notable type is the smart polymeric material based on positive temperature coefficient (PTC). , These materials are conductive polymer composites (CPCs) that exhibit a sharp increase in electrical resistivity as temperature rises, resulting from the mismatch in thermal expansion coefficient between the polymer matrix and the filler. , However, a significant challenge in preparing these stimulus-responsive materials with a PTC effect lies in the poor compatibility between the inorganic conductive filler and the polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

Degradable and Biobased Covalent Adaptable Networks for Light Controllable Switch

Ma,

Wang,

Zhao

et al. 2024

ACS Sustainable Chem. Eng.

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In this study, we successfully synthesized ligninbased covalent adaptable polyurethane networks containing ligningraphite nanosheet composite particles with a light controllable positive temperature coefficient (LPTC) effect. The use of lignin facilitated the direct exfoliation of graphite, thus overcoming the challenge of achieving a uniform dispersion of conductive fillers in the polymer matrix. The exfoliated graphite had a thickness of approximately 3.0 nm, which was equivalent to three to five layers of graphene. By preparing lignin-based covalent adaptable polyurethane without graphite composite particles (LPU) and lignin-based covalent adaptable polyurethane with graphite composite particles (LPU-G), we achieved remoldable properties and a high LPTC intensity for LPU-G. LPU-60G (60 represents the mass fraction of lignin-graphite nanosheets in polyols) exhibited an excellent LPTC effect, with sharp increases in resistance under light, particularly under near-infrared light (NIR), enabling the control of the current in circuits. Additionally, both LPU and LPU-G demonstrated degradability by slowly degrading in a PBS solution while rapidly degrading in an alkaline solution. Overall, the LPU-G synthesized in this study displayed superior stability in the LPTC effect and possessed degradability, providing a promising avenue for the future development of smart materials.

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Self-Sensing Carbon Nanotube Composites Exposed to Glass Transition Temperature

Cited by 15 publications

References 28 publications

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

Crack Detection of Reinforced Concrete Structure Using Smart Skin

Degradable and Biobased Covalent Adaptable Networks for Light Controllable Switch

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