• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.32.1-32.1
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• 2009

현재 ITO를 대체할 재료로 투명 전도성 탄소나노튜브(carbon nanotube, CNT) 필름에 대한 연구가 진행 되고 있다. 이러한 연구에서 특히 CNT 필름의 투과도에 따른 전기저항을 향상시키기 위한 연구가 활발히 진행되고 있다. 본 연구에서는 단일벽 CNT (single-walled CNT)를 여러 가지 계면활성제로 최적 분산시킨 수용액으로부터 제조한 CNT 필름의 투과도에 따른 면 저항 (sheet resistance) 변화를 관찰하였다. 우선 계면활성제로 분산시킨 CNT 수용액을 알루미나 재질의 필터에서 정량적으로 진공 필터링하여 CNT 필름을 제조하였다. 알루미나 필터를 sodium hydroxide (NaOH) 수용액으로 용해시켜 제거함으로써 얻은 CNT 필름을 유리기판 위에 부착시켰다. 필름의 전기저항을 낮추기 위해 유리기판 위에 부착된 CNT 필름을 질산 (HNO3) 용액으로 처리하였다. Scanning electron microscopy, UV-Vis spectroscopy를 이용하여 각각 필름의 형상과 광 투과도를 분석하였고, 4-point probe로 면 저항을 측정하였다. 계면활성제로 분산시킨 CNT 필름 대부분의 면 저항은 질산 처리에 의해 감소하였다. 이는 CNT 표면에 코팅되어 있던 계면활성제가 질산에 의해 제거되었기 때문인 것으로 예상된다. 여러 계면활성제 중 sodium dodecyl benzenesulfonate로 분산시킨 CNT 필름이 산 처리 후에 가장 낮은 면 저항을 보였다. 그리고 Polyvinyl pyrrolidone (PVP)과 cetyltrimethylammonium bromide (CTAB)를 사용하여 제조한 CNT 필름의 면 저항이 가장 뚜렷한 감소를 보였다.

• Structural Monitoring and Maintenance
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• v.9 no.3
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• pp.259-270
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• 2022

This study explores the use of the recently developed "strain-sensing smart skin" (S⁴) method for noncontact strain measurements on cement-based samples. S⁴ sensors are single-wall carbon nanotubes dilutely embedded in thin polymer films. Strains transmitted to the nanotubes cause systematic shifts in their near-infrared fluorescence spectra, which are analyzed to deduce local strain values. It is found that with cement-based materials, this method is hampered by spectral interference from structured near-infrared cement luminescence. However, application of an opaque blocking layer between the specimen surface and the nanotube sensing film enables interference-free strain measurements. Tests were performed on cement, mortar, and concrete specimens with such modified S⁴ coatings. When specimens were subjected to uniaxial compressive stress, the spectral peak separations varied linearly and predictably with induced strain. These results demonstrate that S⁴ is a promising emerging technology for measuring strains down to ca. 30 𝜇𝜀 in concrete structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.97-98
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• 2009

Here, we describe a versatile strategy for precise control of the optoelectrical properties of the single walled carbon nanotube (SWNT)/silane binder hybrid films by noncovalent hybridization. Stable SWNT/silane binder solutions were prepared by direct mixing of high concentration CNT solutions and silane sol solutions. The critical binder content was determined by varying the amount of binder in the SWNT/binder solutions. A binder content of 50 wt% was used to prepare the other SWNT/binder solutions. This study demonstrates how the intermolecular interactions between the SWNTs and the silanes can affect the conductivity of the CNT/binder network films by characterizing the optoelectrical and Raman spectroscopic properties of the SWNT/silane films containing silane binders with various functional groups. The use of the PTMS binder with phenyl groups was found to be most effective in the fabrication of transparent and conductive films on glass substrates. Such a precise control of the optoelectrical properties of SWNT/binder films can be useful to fabricate the high performance conductive thin films, with ramifications for understanding the fundamental intermolecular interaction in carbon materials science.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.410-410
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• 2009

현재 탄소나노튜브 (carbon nanotube, CNT)를 여러 분야에 응용하기 위해 다양한 연구가 진행되고 있다. 본 논문에서는 단일벽 CNT (single-walled CNT)를 여러 가지 계면활성제로 최적 분산시킨 수용액으로부터 제조한 투명 전도성 필름을 터치스크린이나 디스 플레이 소자에 응용할 목적으로 필름의 전기저항 및 광 투과도를 향상시키기 위한 연구를 수행하였다. 우선 계면활성제로 분산시킨 정량의 CNT 수용액을 알루미나 재질의 필터에서 진공 필터링하여 CNT 필름을 제조하였다. 알루미나 필터를 sodium hydroxide (NaOH) 수용액으로 용해시켜 제거하여 얻은 CNT 필름을 유리기판 위에 부착시켰다. 필름의 전기저항을 낮추기 위해 유리기판 위에 부착된 CNT 필름을 질산($HNO_3$) 용액으로 처리하였다. Scanning electron microscopy, UV-Vis spectroscopy를 이용하여 각각 필름의 형상과 광투과도를 분석하였고, 4-point probe로 면 저항을 측정하였다. 계면활성제로 분산시킨 대부분의 CNT 필름의 면 저항은 질산 처리에 의해 감소하였다. 이는 CNT 표면에 코팅되어 있던 계면활성제가 질산에 의해 제거되었기 때문인 것으로 예상된다. 그리고 anionic 계면활성제를 이용한 필름이 대체로 낮은 면 저항을 보였고, 그중 분산력이 가장 좋은 sodium dodecyl benzenesulfonate(SDBS)가 최저의 면 저항을 나타내었다. 질산처리에서 Polyvinyl pyrrolidone(PVP)과 cetyltrimethylammonium bromide(CTAB)를 사용하여 제조한 CNT 필름의 면 저항이 가장 뚜렷한 감소를 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.426-426
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• 2007

We report the field emission characteristics of transparent single-walled carbon nanotube (SWNT) film printed using an inkjet. Pure SWNTs dispersed in dimethylformamide were printed in a transparent layer on indium-tin oxide-coated glass and annealed at $350^{\circ}C$. After taping treatment, SWNTs were oriented vertically on the substrate. The front and the back of the fabricated device produced simultaneous emissions of identical quality. In addition, inkjet printing directly achieved a patterned emission, without a secondary pattern process. This method allows simple fabrication using only SWNTs, without the use of other additives.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.131-136
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• 2011

Many researchers are recently studying about Electroactive polymer(EAP). But it has a physical limitation, because of property of material. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. This study focuses on the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. To come up with mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we dispersed Single-walled carbon nanotubes(SWCNTs). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. We fabricated a disperse SWCNT/Nafion composite uniformly. Through the use of the E-beam evaporator to form an uniform electrode layer, we consummated the IPMC actuator. This result shows improving 1.5 times mechanical properties about driving force in IPMC.

• Steel and Composite Structures
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• v.14 no.4
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• pp.335-347
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• 2013

In this paper, the nonlinear cylindrical bending behavior of functionally graded nanocomposite plates reinforced by single-walled carbon nanotubes (SWCNTs) is studied using an efficient and simple refined theory. This theory is based on assumption that the in-plane and transverse displacements consist of bending and shear components in which the bending components do not contribute toward shear forces and, likewise, the shear components do not contribute toward bending moments. The material properties of SWCNTs are assumed to be temperature-dependent and are obtained from molecular dynamics simulations. The material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTCRs) are assumed to be graded in the thickness direction, and are estimated through a micromechanical model. The fundamental equations for functionally graded nanocomposite plates are obtained using the Von-Karman theory for large deflections and the solution is obtained by minimization of the total potential energy. The numerical illustrations concern the nonlinear bending response of FG-CNTRC plates under different sets of thermal environmental conditions, from which results for uniformly distributed CNTRC plates are obtained as comparators.

• Structural Engineering and Mechanics
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• v.67 no.2
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• pp.125-130
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• 2018

This study deals with buckling analysis with stretching effect of functionally graded carbon nanotube-reinforced composite beams resting on an elastic foundation. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are estimated by using the rule of mixture. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The equilibrium equations have been obtained using the principle of virtual displacements. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of buckling analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. the effects of different parameters of the beam on the buckling responses of CNTRC beam are discussed.

• Journal of the Korean institute of surface engineering
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• v.57 no.3
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• pp.214-220
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• 2024

In this study, three-dimensional (3D) networks structure using single-walled carbon nanotubes (SWCNTs) for Si-graphite composite electrode was developed and studied about effects on the electrochemical performances. To investigate the effect of SWCNTs on forming a conductive 3D network structure electrode, zero-dimensional (0D) carbon black and different SWCNTs composition electrode were compared. It was found that SWCNTs formed a conductive network between nano-Si and graphite particles over the entire area without aggregation. The formation of 3D network structure enabled to effective access for lithium ions leading to improve the c-rate performance, and provided cycle stability by alleviating the Si volume expansion from flexibility and buffer space. The results of this study are expected to be applicable to the electrode design for high-capacity lithium-ion batteries.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.28-34
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• 2011

In previous reports, we investigated a selective assembly method of fabricating single-walled carbon nanotubes (SWCNTs) on a silicon-dioxide ($SiO_2$) surface by using only a photolithographic process. In this paper, we have fabricated field effect transistors (FETs) with SWCNT channels by using the technique mentioned above. Also, we have electrically measured gating effects of these FETs under different source-drain voltages ($V_{SD}$). These FETs have been fabricated for sensor applications. Photoresist (PR) patterns have been made on a $SiO_2$-grown silicon (Si) substrate by using a photolithographic process. This PR-patterned substrate have been dipped into a SWCNT solution dispersed in dichlorobenzene (DCB). These PR patterns have been removed by using aceton. As a result, a selectively-assembled SWCNT channels in FET arrays have been obtained between source and drain electrodes. Finally, we have successfully fabricated 4 FET arrays based on SWCNT-channels by using our simple self-assembly technique.