• 공업화학
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• 제22권3호
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• pp.266-271
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• 2011

단일벽 탄소나노튜브(single-walled carbon nanotube, SWCNT)의 우수한 열적 특성을 이용하여 에폭시 수지의 열전도도 특성을 향상시키기 위해 SWCNT와 에폭시 수지 복합체를 제작하여 열전도도를 측정하였다. SWCNT에 카보닐기와 아민기를 도입하여 분산도 향상을 유도하였으며 diglycidyl ether of bisphenol A (DGEBA)와 bisphenol F (DGEBF) 두 종류의 에폭시 레진에 각각의 SWCNT를 첨가하여 제작한 복합체들은 파단면 분석을 통하여 분산 특성을 관찰하였다. 각 복합체의 분산도는 표면 처리를 거치면서 생성된 극성분자와 에폭시 간의 상호작용으로 인하여 SWCNT를 첨가한 것이 순수한 SWCNT 복합체와 비교하여 높은 분산성을 나타내었다. SWCNT/에폭시 복합체의 열전도도는 DGEBA와 DGEBF 두 종류의 에폭시에서 산처리한 SWCNT 복합체가 가장 높은 값을 가지는 것으로 측정되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1083-1088
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• 2003

Molecular dynamics simulations on the deformation behavior of single-walled carbon nanotube are performed. Formation energies of CNT's by interatomic potentials are computed and compared with ab initio results. Bending and axial compression are applied under lattice statics and NVT ensemble conditions. Specifically, we focus on the mechanism of kink formation in bending. The simulation results are comprehensively explained in the framework of atomistic energetics. The effects of temperature and chirality on the deformation of carbon nanotube are also studied.

• 한국전자파학회논문지
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• 제19권8호
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• pp.891-898
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• 2008

본 논문에서는 인터디지털 커패시트 기반의 단일벽 탄소 나노 튜브(single-walled carbon nanotube, SWNT)를 이용한 바이오 물질 검출에 관한 연구를 수행하였다. 먼저 인터디지털 커패시트의 경우, 다음으로 $5\;{\mu}m$ 틈 사이에 SWNT 경우, 그리고 SWNT 상에 biotin이 고정된 경우, 마지막으로 biotin과 streptavidin이 고정화된 경우, 공진 주파수는 각각 10.02 GHz, 11.02 GHz, 10.82 GHz, 10.22 GHz로 나타났다. 이러한 공진 주파수의 민감한 변화는 유전 상수값이 다른 두 바이오 물질이 결합함에 따라 커패시턴스 값이 달라질 것이라는 가정 하에, 측정된 결과를 근거로 등가회로를 구현함으로써 실제로 커패시턴스 값들이 달라짐을 확인할 수 있었다. SWNT 상에 biotin이 고정된 경우와 biotin과 streptavidin이 고정화된 경우, 커패시턴스 값은 각각 $C_b=0.55\;pF$, $C_s=0.95\;pF$으로 나타났다. 본 연구를 통해서, 탄소 나노 튜브상에 특정 바이오 물질간의 결합이 커패시턴스 값의 변화를 유발시키게 되고, 이로 인해서 공진 주파수가 변화됨을 실험적으로 증명하였다. 결론적으로, 제안된 바이오 센싱 소자는 표적 바이오 물질(streptavidin)이 결합할 때 큰 공진 주파수 변화를 일으킴으로 CNT 바이오센서로서 충분한 가능성이 있음을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.559-562
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• 2004

Carbon nanotube is a geometrical frame-like structure and the primary bonds between two nearest-neighboring atoms act like beam members, whereas an individual atom acts as the joint of the related beam members. The sectional property parameters of these beam members are obtained from molecular mechanics. Computations of the elastic deformation of single-walled carbon nanotubes reveal that the Young's moduli of carbon nanotubes vary with the tube diameter and are affected by their helicity. With increasing tube diameter, the Young's moduli of carbon nanotubes approach the Young's modulus of graphite.

• Advances in materials Research
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• 제3권2호
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• pp.77-89
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• 2014

In the present article, the thermal buckling of zigzag single-walled carbon nanotubes (SWCNTs) is studied using a nonlocal refined shear deformation beam theory and Von-Karman geometric nonlinearity. The model developed simulates both small scale effects and higher-order variation of transverse shear strain through the depth of the nanobeam. Furthermore the present formulation also accommodates stress-free boundary conditions on the top and bottom surfaces of the nanobeam. A shear correction factor, therefore, is not required. The equivalent Young's modulus and shear modulus for zigzag SWCNTs are derived using an energy-equivalent model. The present study illustrates that the thermal buckling properties of SWCNTs are strongly dependent on the scale effect and additionally on the chirality of zigzag carbon nanotube. Some illustrative examples are also presented to verify the present formulation and solutions. Good agreement is observed.

• Earthquakes and Structures
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• 제13권5호
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• pp.509-518
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• 2017

The objective of the present paper is to investigate the bending behavior with stretching effect of carbon nanotube-reinforced composite (CNTRC) beams. The beams resting on the Pasternak elastic foundation, including a shear layer and Winkler spring, are considered. 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 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 assessed by employing the rule of mixture. 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 bending 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 bending responses of CNTRC beam are discussed.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1215-1220
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• 2011

An electrochemically-modified electrode [P(EDOP-SWNTs)/GCE] was prepared by electropolymerization of 3,4-ethylenedioxy pyrrole (EDOP) single-walled carbon nanotubes (SWNTs) on the surface of a glassy carbon electrode (GCE) and characterized by SEM, CV, and DPV. This modified electrode was employed as an electrochemical biosensor for the selective determination of serotonin concentrations at pH 7.4 and exhibited a typical enhanced effect on the current response of serotonin with a lower oxidation overpotential. The linear response was in the range of $1.0{\times}10^{-7}$ to $1.0{\times}10^{-5}$ M, with a correlation coefficient of 0.998 on the anodic current. The lower detection limit was calculated as 5.0 nM. Due to the relatively low currents and difference of potentials in the electrochemical responses of uric acid (UA), ascorbic acid (AA), and dopamine (DA), the modified electrode was a useful and effective sensing device for the selective and sensitive serotonin determination in the presence of UA, AA, and DA.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.402-410
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• 2008

Single-walled carbon nanotubes (SWCNTs) were currently produced together with some contaminants such as a metallic catalyst, amorphous carbon, and graphitic nanoparticles, which should be sometimes purified for their applications. This study aimed to develop efficient, scalable purification processes but less harmful to SWCNTs. We designed three-step purification processes: acidic treatment, surface functionalization and soxhlet extraction, and heat treatment. During the soxhlet extraction using tetrahydrofuran, specifically, carbon impurities could be easily expelled through a glass thimble filter without any significant loss of CNTs. Finally, SWCNTs were left as a bulky paper on the filter through membrane filtration. Vertically aligned SWCNTs on one side of bulky paper were well developed in a speparation from the filter paper, which were formed by being sucked through the filter pores during the pressurized filtration. The bucky paper showed a very high peak current density of field emission up to $200\;mA/cm^2$ and uniform field emission images on phosphor, which seems very promising to be applied to vacuum microelectronics such as microwave power amplifiers and x-ray sources.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.201-201
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• 2012

Using materials with high thermal conductivity is a matter of great concern in the field of thermal management. In this study, we present our experimental results on an important physical property of carbon nanotube (CNT) films, two-dimensional thermal conductivity obtained by using an optical method based on Raman spectroscopy. We prepared four kinds of CNT films to investigate the effect of CNT type on heat spreading performance of films. This first comparative study using the optical method shows that the arc-discharge single-walled carbon nanotubes yield the best heat spreading film. And we observed thermal conductivity values of CNT films with various transmittances and found that the Raman method works as long as the sample is a transparent film. This study provides useful information on characterization of thermal conduction in transparent CNT films and could be an important step toward high-performance carbon-based heat spreading films.

• Steel and Composite Structures
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• 제46권5호
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• pp.637-647
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• 2023

Nonlinear free vibration and stability responses of a carbon nanotube reinforced composite beam under temperature rising are investigated in this paper. The material of the beam is considered as a polymeric matrix by reinforced the single-walled carbon nanotubes according to different distributions with temperature-dependent physical properties. With using the Hamilton's principle, the governing nonlinear partial differential equation is derived based on the Euler-Bernoulli beam theory. In the nonlinear kinematic assumption, the Von Kármán nonlinearity is used. The Galerkin's decomposition technique is utilized to discretize the governing nonlinear partial differential equation to nonlinear ordinary differential equation and then is solved by using of multiple time scale method. The critical buckling temperatures, the nonlinear natural frequencies and the nonlinear free response of the system is obtained. The effect of different patterns of reinforcement on the critical buckling temperature, nonlinear natural frequency, nonlinear free response and phase plane trajectory of the carbon nanotube reinforced composite beam investigated with temperature-dependent physical property.