Linearly Sensitive and Flexible Pressure Sensor Based on Porous Carbon Nanotube/Polydimethylsiloxane Composite Structure

Jung, Young Jin; Jung, Kyung Kuk; Kim, Dong Hwan; Kwak, Dong Hwa; Ko, Jong Soo

doi:10.3390/polym12071499

Cited by 35 publications

(23 citation statements)

References 34 publications

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“…In order to overcome the mechanical and thermal shortcomings of PDMS, extensive research has focused on improving the material properties using different fillers. Carbon nanofibers and nanotubes [ 18 , 19 , 20 ], graphite [ 21 ], graphene [ 22 ], nanodiamond [ 23 ], carbon black [ 18 ], silica [ 24 ], nanoclay [ 25 ], and other fillers have all been used to improve the properties of PDMS and other polymer materials. Specifically, carbon fibers have several qualities that make them an appropriate filler for polymer materials.…”

Section: Introductionmentioning

confidence: 99%

Tuning Thermal and Mechanical Properties of Polydimethylsiloxane with Carbon Fibers

2021

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In order to meet the needs of constantly advancing technologies, fabricating materials with improved properties and predictable behavior has become vital. To that end, we have prepared polydimethylsiloxane (PDMS) polymer samples filled with carbon nanofibers (CFs) at 0, 0.5, 1.0, 2.0, and 4.0 CF loadings (w/w) to investigate and optimize the amount of filler needed for fabrication with improved mechanical properties. Samples were prepared using easy, cost-efficient mechanical mixing to combine the PDMS and CF filler and were then characterized by chemical (FTIR), mechanical (hardness and tension), and physical (swelling, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and coefficient of thermal expansion) analyses to determine the material properties. We found that hardness and thermal stability increased predictably, while the ultimate strength and toughness both decreased. Repeated tension caused the CF-filled PDMS samples to lose significant toughness with increasing CF loadings. The hardness and thermal degradation temperature with 4 wt.% CF loading in PDMS increased more than 40% and 25 °C, respectively, compared with the pristine PDMS sample. Additionally, dilatometer measurements showed a 20% decrease in the coefficient of thermal expansion (CTE) with a small amount of CF filler in PDMS. In this study, we were able to show the mechanical and thermal properties of PDMS can be tuned with good confidence using CFs.

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Section: Introductionmentioning

confidence: 99%

Tuning Thermal and Mechanical Properties of Polydimethylsiloxane with Carbon Fibers

2021

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“…This structural stability was attributed to the embedded CNTs in the PDMS frame. 7 The variations in the surface composition were quantitatively analyzed using XPS (Figure 1d). The C−Si peak is a characteristic peak of PDMS, and it was observed at 284.38 eV in the XPS C1s spectrum of the porous pristine PDMS.…”

Section: Resultsmentioning

confidence: 99%

“…These sensors can be utilized for diverse practical applications such as in electronic skin, , health monitoring, − and human–machine interfaces . The fabrication of different pressure sensors, such as piezoresistive, − capacitive, , piezoelectric, and triboelectric, − with various sensing mechanisms has been reported thus far. Capacitive sensors are flexible pressure sensors that transduce an applied pressure into a capacitance signal, and they are extensively utilized owing to their simple design, high stability, and low hysteresis .…”

Section: Introductionmentioning

confidence: 99%

Linearly Sensitive Pressure Sensor Based on a Porous Multistacked Composite Structure with Controlled Mechanical and Electrical Properties

Jung

Lee

et al. 2021

ACS Appl. Mater. Interfaces

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Capacitive pressure sensors based on porous structures have been extensively explored for various applications because their sensing performance is superior to that of conventional polymer sensors. However, it is challenging to develop sufficiently sensitive pressure sensors with linearity over a wide pressure range owing to the trade-off between linearity and sensitivity. This study demonstrates a novel strategy for the fabrication of a pressure sensor consisting of stacked carbon nanotubes (CNTs) and polydimethylsiloxane. With the addition of carbon nanotubes, the structure is linearly compressed due to the reinforced mechanical properties, thereby resulting in high linearity. Additionally, the percolation effect is boosted by the CNTs having a high dielectric constant, thus improving the sensitivity. The pressure sensor exhibits linear sensitivity (R 2 = 0.991) in the medium-pressure range (10−100 kPa). Furthermore, it delivers excellent performance with a fast response time (∼60 ms), in conjunction with high repeatability, reproducibility, and reliability (5 and 50 kPa/1000 cycles). The fabricated sensors are applied in wearable devices to monitor finger bending and detect finger motions in real time with high precision. The large-area sensor is integrated with a neural network to accurately recognize the sitting posture on a plane, thereby demonstrating the wide-range detection performance.

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“…[ 4–6 ] For many of these applications involving low pressure detection such as wrist pulse or soft touch (0–10 kPa), high sensitivity in the low‐pressure range are required. Pressure sensing mechanisms can be divided into piezoresistive, [ 7–12 ] piezocapacitive, [ 13–17 ] piezoelectric, [ 18,19 ] or piezotransmittance [ 20–22 ] types. Piezoresistive flexible pressure sensors convert physical stimuli into a change in electrical resistance by changing the contact area and pressure between electrodes and sensor structures.…”

Section: Introductionmentioning

confidence: 99%

Irregular Microdome Structure‐Based Sensitive Pressure Sensor Using Internal Popping of Microspheres

Jung

Choi

Lee

et al. 2022

Adv Funct Materials

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Modifying the surface morphology of an elastomer surface into 3D microstructures is crucial for various soft sensor applications. However, processes based on typical mold microfabrication and elastomer casting remain the dominant methodologies. This study demonstrates a novel strategy for generating 3D and irregular microdome structures for flexible pressure sensors through the internal popping of microspheres. When thermal treatment is applied to a composite film composed of microspheres and an elastomer matrix, the microspheres expand, and irregular microdome structures are generated. This composite film with an irregular microdome structure is utilized as a piezoresistive pressure-sensing film. The sensor shows high sensitivity (−50.45 kPa −1 ) owing to the heterogeneous contact change between the irregular microdome structure and a laser-induced graphene electrode; it also exhibits a short response time (τ 10-90% ≈ 39 ms), excellent repeatability, and high reliability. The sensor is applied in a fingertip-shaped pressure sensor to detect the blood pulse on the index finger and on electronic skin to recognize soft objects. Furthermore, a pressure sensor array that enables various functions such as drawing, multitouch, and deep learning-based motion control, is demonstrated.

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Linearly Sensitive and Flexible Pressure Sensor Based on Porous Carbon Nanotube/Polydimethylsiloxane Composite Structure

Cited by 35 publications

References 34 publications

Tuning Thermal and Mechanical Properties of Polydimethylsiloxane with Carbon Fibers

Tuning Thermal and Mechanical Properties of Polydimethylsiloxane with Carbon Fibers

Linearly Sensitive Pressure Sensor Based on a Porous Multistacked Composite Structure with Controlled Mechanical and Electrical Properties

Irregular Microdome Structure‐Based Sensitive Pressure Sensor Using Internal Popping of Microspheres

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