On the mechanism of piezoresistivity of carbon nanotube polymer composites

Gong, Shen; Zhu, Zheng H.

doi:10.1016/j.polymer.2014.06.024

Cited by 103 publications

(78 citation statements)

References 62 publications

(102 reference statements)

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“…[ 10 ] CNTspolymer composites based strain sensors typically exhibited nonlinear electromechanical performance with low sensitivity. [ 32,42,48,49,59,71,[111][112][113] Both sensitivity and linearity of the CNTs-polymer composites were improved by their hybrid structures. For instance, metal-coated CNT-epoxy nanocomposites (GFs ≈ 155) (Figure 4 d) and CNTs-graphite fl ake hybrid thin fi lm coated on PET (GFs ≈ 7.8) showed high linearity and sensitivity, but with very low stretchability (ε ≤ 1.5%).…”

Section: Linearitymentioning

confidence: 99%

“…Neglecting the intrinsic piezoresistivity of CNTs, elastic behavior of individual CNT as well as deformation of CNT walls transversely in the CNT-CNT junctions overestimated the overall conductance and piezoresistive behavior of CNTs-polymer nanocomposites. [ 35,112,119,120 ] Recently, the validation of simulation results was remarkably improved by considering the deformation of CNT walls in the contact areas. [ 112,121 ] It was demonstrated that the increase of the contact resistance due to the increase of the intrinsic resistance of CNT cause by the wall deformation is signifi cant.…”

Section: Computational Analysismentioning

confidence: 99%

“…[ 35,112,119,120 ] Recently, the validation of simulation results was remarkably improved by considering the deformation of CNT walls in the contact areas. [ 112,121 ] It was demonstrated that the increase of the contact resistance due to the increase of the intrinsic resistance of CNT cause by the wall deformation is signifi cant. Simulations indicated that the tunneling resistance change is the main mechanism of the piezoresistivity of CNTs-polymer nanocomposite strain sensors.…”

Section: Computational Analysismentioning

confidence: 99%

“…Simulations indicated that the tunneling resistance change is the main mechanism of the piezoresistivity of CNTs-polymer nanocomposite strain sensors. [ 107,108,110,112 ] The nonlinearity of CNTspolymer nanocomposite strain sensors was referred to the nonlinear tunneling effect. Moreover, the effects of parameters such as size, shape, tunneling area, and height of barrier on the piezoresistivity of the CNTs-polymer nanocomposites were extensively studied.…”

Section: Computational Analysismentioning

confidence: 99%

“…Moreover, the effects of parameters such as size, shape, tunneling area, and height of barrier on the piezoresistivity of the CNTs-polymer nanocomposites were extensively studied. [ 42,108,112,119 ] However, all abovementioned papers explored the piezoresistivity of the CNTs-polymer nanocomposites under small strains (ε ≤ 1%). [ 35,42,107,122 ] Strainresponsive behavior of CNTs-polymer nanocomposites at larger strains needs further investigations.…”

Section: Computational Analysismentioning

confidence: 99%

See 4 more Smart Citations

Stretchable, Skin‐Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review

Amjadi

Kyung

Park

et al. 2016

Adv Funct Materials

2,549

2,129

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wileyonlinelibrary.comSkin-mountable and wearable sensors can be attached onto the clothing or even directly mounted on the human skin for the real-time monitoring of human activities. [ 10 ] Besides their high effi ciency, they must fulfi ll several minimum requirements including high stretchability, fl exibility, durability, low power consumption, biocompatibility, and lightweight. These demands become even more severe for epidermal electronic devices where mechanical compliance like human skin and high stretchability ( ε > 100% where ε is the strain) are required. [ 11,12 ] Recently, several types of skin-mountable and wearable sensors have been proposed by using nanomaterials coupled with fl exible and stretchable polymers. Indeed, nanomaterials are utilized as functional sensing elements owing to their outstanding electrical, mechanical, optical, and chemical properties while polymers are employed as fl exible support materials thanks to their fl exibility, stretchability, humanfriendliness, and durability. [ 13 ] Examples of those innovative sensors include strain sensors, [ 10,[12][13][14] pressure sensors, [ 5,[15][16][17] electronic skins (e-skins), [ 3,[16][17][18][19][20] and temperature sensors. [ 2,21,22 ] Particularly, various skin-mountable and wearable strain sensors have been developed because of their broad applications in personalized heath-monitoring, human motion detection, human-machine interfaces, and soft robotics. [ 10,12,[23][24][25][26][27][28][29][30][31] This paper aims to survey fabrication processes, working mechanisms, strain sensing performances, and applications of stretchable strain sensors. The article is organized as follows: fi rst, common operation mechanisms of stretchable strain sensors are described. Here, we summarize novel functional nanomaterials and techniques for the fabrication of stretchable strain sensors in details. Second, mechanisms involved in the strain-responsive behavior of resistive-type and capacitive-type sensors are explained. We show that the infl uence of traditional mechanisms like geometrical changes and piezoresistivity of materials on the strain sensing performance of fl exible strain sensors are very small whereas mechanisms such as disconnection between sensing elements, crack propagation in thin fi lms, and tunneling effect can potentially be employed for highly stretchable and sensitive strain sensing. Third, we emphasize the performance parameters of stretchable strain sensors in terms of stretchability, sensitivity, linearity, hysteresis behavior, response time, overshooting, and durability. We demonstrate

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Section: Linearitymentioning

confidence: 99%

Section: Computational Analysismentioning

confidence: 99%

Section: Computational Analysismentioning

confidence: 99%

Section: Computational Analysismentioning

confidence: 99%

Section: Computational Analysismentioning

confidence: 99%

See 3 more Smart Citations

Stretchable, Skin‐Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review

Amjadi

Kyung

Park

et al. 2016

Adv Funct Materials

2,549

2,129

View full text Add to dashboard Cite

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3D Printing of Highly Stretchable Strain Sensors Based on Carbon Nanotube Nanocomposites

et al. 2018

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This paper presents the additive manufacturing of a stretchable and electrically conductive polydimethylsiloxane (PDMS) nanocomposite for strain sensing. A long, thin PDMS strip in a zig‐zag pattern of five parallel lines is 3D printed on elastomer substrate using an in‐house modified 3D printer. Multi‐walled carbon nanotubes (MWCNTs) are uniformly deposited on the uncured PDMS lines and cured in an oven. An additional layer of PDMS is then applied on top of MWCNTs to form a thin protective coating. The 3D printed PDMS/MWCNT nanocomposites are characterized using a scanning electron microscope (SEM) to validate the thickness, uniformity, and microstructural features of the sensor cross‐section. The strain sensing capability of the nanocomposites is investigated under tensile cyclic loading at different strain rates and maximum strains. Long‐term performance is tested under cyclic tensile loads for 300 cycles. Sensing experiments indicate that under cyclic loading, the changes in piezo resistivity mimic the changes in the applied load and the measured material strain with high fidelity. In situ micro‐mechanical testing in SEM is carried to investigate the piezoresistive sensing mechanism. Due to the high flexibility of PDMS, the 3D printed sensors are tested to monitor the bending of a human wrist joint as a wearable sensor.

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Multifunctionality of Nanoengineered Self‐Sensing Lattices Enabled by Additive Manufacturing

et al. 2022

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Lightweight cellular materials are engineered to enhance performance attributes such as energy absorption, specific stiffness, negative Poisson's ratio, negative thermal expansion coefficient, etc. However, self‐sensing functionality of such architected materials is seldom explored. Herein, a combined experimental and numerical study on additive manufacturing (AM)‐enabled self‐sensing cellular composites processed via fused filament fabrication, utilizing in‐house engineered multiwall carbon nanotube (MWCNT)/polypropylene random copolymer (PPR) filament feedstocks, is reported. The tunable self‐sensing and enhanced mechanical performance of PPR/MWCNT lattices are experimentally demonstrated by varying their architectural parameters in addition to the MWCNT content. The lattices reveal strain and damage sensitivity gauge factors of 12 and 1.2, respectively, comparable to bulk materials’ commercial gauge factors. Furthermore, self‐sensing lattices exhibit 200%, 155%, 153%, and 137% increase in stiffness, energy absorption capacity (as high as 4.7 MJ m−3), specific energy absorption (20.5 J g−1), and energy absorption efficiency (90%), respectively, compared with their non‐reinforced counterparts. The tunable multifunctional performance of AM‐enabled cellular composites demonstrated here provides guidelines for the design and development of composite lattices with advantaged structural and functional properties for an array of applications such as patient‐specific biomedical devices capable of measuring comfort in prosthetics.

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On the mechanism of piezoresistivity of carbon nanotube polymer composites

Cited by 103 publications

References 62 publications

Stretchable, Skin‐Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review

Stretchable, Skin‐Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review

3D Printing of Highly Stretchable Strain Sensors Based on Carbon Nanotube Nanocomposites

Multifunctionality of Nanoengineered Self‐Sensing Lattices Enabled by Additive Manufacturing

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