A nonlocal integral Timoshenko beam model for free vibration analysis of SWCNTs under thermal environment

Liani, Mohamed,Moulay, Noureddine,Bourada, Fouad,Addou, Farouk Yahia,Bourada, Mohamed,Tounsi, Abdelouahed,Hussain, Muzamal Techno-Press 2022 Advances in materials research Vol.11 No.1

In this paper, the nonlocal integral Timoshenko beam model is employed to study the free vibration characteristics of singled walled carbon nanotubes (SWCNTs) including the thermal effect. Based on the nonlocal continuum theory, the governing equations of motion are formulated by considering thermal effect. The influences of small scale parameter, the chirality of SWCNTs, the vibrational mode number, the aspect ratio of SWCNTs and temperature changes on the thermal vibration properties of single-walled nanotubes are examined and discussed. Results indicate significant dependence of natural frequencies on the nonlocal parameter, the temperature change, the aspect ratio and the chirality of SWCNTs. This work should be useful reference for the application and the design of nanoelectronics and nanoelectromechanical devices that make use of the thermal vibration properties of SWCNTs.

Parametric vibration analysis of single-walled carbon nanotubes based on Sanders shell theory

Khadimallah, Mohamed A.,Hussain, Muzamal,Taj, Muhammad,Ayed, Hamdi,Tounsi, Abdelouahed Techno-Press 2021 Advances in nano research Vol.10 No.2

This paper based on Sanders theory aims to investigate the vibration of SWCNTs considering the clamped-simply supported, clamped-free, clamped-clamped and simply supported-simply supported end conditions. After developing the governing equation of the objective system, the Rayleigh-Ritz technique is implemented for the purpose of obtaining the frequency equation in the eigen form. In addition, the applicability of this model for the analysis of vibration of CNTs is examined with the effect of length and ratio of height-to-radius. A detailed description of different types of SWCNTs with different indices is provided in the theoretical methodology. The effect of extended length is stimulated with increasing the radii and the model is effective because it also predicts the effect of thickness on vibration of SWCNTs. For different boundary conditions, the present results are verified with earlier literature.

Single-wall carbon nanotube modified with copper-oxamate flat complex probed by synchrotron x-ray photoelectron and x-ray absorption spectroscopies

Do Nascimento, Gustavo M.,Do Pim, Walace D.,Endo, Morinobu,Choi, go Bong,Kim, Yoong Ahm,Pradie, Noriberto A.,Stumpf, Humberto O. Elsevier 2019 Journal of molecular structure Vol.1176 No.-

<P><B>Abstract</B></P> <P>Nanocomposites formed from the precursor of molecule-based magnets [Cu(opba)]<SUP>2−</SUP> [opba = <I>o</I>-phenylenebis(oxamate)] and single-wall carbon nanotubes (SWCNTs) were characterized by X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) at Carbon and Nitrogen <I>K</I> edges and Cu <SUB> L 2,3 </SUB> edges. The N <I>K</I> XANES, XPS and micro-ATR-FTIR data strongly suggested that [Cu(opba)]<SUP>2−</SUP> molecules be flatly bonded onto the surface of the SWCNTs. Therefore, higher charge delocalization and electronic modifications were observed. The presence of a new band at 286.1 eV in the Carbon peak of XPS spectra of nanocomposites was assigned to the Carbon surface of the SWCNTs modified by interaction with the metal complex. The micro-ATR-FTIR data supported by DFT calculations show many changes in the bands related to νC = C and νC = O groups of the metal complex in the nanocomposites. Such changes confirmed that the vibrational properties of the complex also changed due to interaction with the carbon nanotubes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> XANES and XPS data of (NBu<SUB>4</SUB>)<SUB>2</SUB>[Cu(opba)]-SWCNT nanocomposites at several atomic edges. </LI> <LI> Micro-ATR-FTIR used for studying the metallic complex over SWCNT surface. </LI> <LI> Oxamate-based complex have strong interaction with SWCNT by −CuN− sites. </LI> </UL> </P>

단일벽 탄소나노튜브를 이용한 플렉시블 폴리에틸렌테레프탈레이트 (PET) 전극의 제조와 특성

두진펑,김장훈,김용렬,정현택 한국유화학회 2016 한국응용과학기술학회지 Vol.33 No.3

본 연구에서는 유연성을 갖는 전극 제조를 위해 산 처리된 단일벽 탄소나노튜브 (Acid treated-SWCNTs)를 금이 코팅된 PET 기판 위에 스프레이 코팅하였다. 단일벽 탄소나노튜브가 가지는 단점을 보완하기 위하여 산 처리 공정을 이용하여 나노튜브에 작용기를 도입하여 분산성을 극대화 시켰 으며 전기화학적 특성을 향상 시켰다. 스프레이 기술을 이용하여 제조된 유연성을 갖는 단일벽 탄소나노 튜브 기반의 전극을 1 M의 황산 전해질에서 순환 전압 전류법, 임피던스 분광법 그리고 충·방전 시험을 통하여 전기화학적 특성을 분석 하였다. 그 결과, 응력을 가하지 않은 전극의 전기 용량값은 67 F․g-1로 측정 되었으며, 1000번의 충·방전 시험 후에는 전기 용량값이 63 F․g-1 (94 % 유지)로 감소하는 결과를 보였다. 이에 반하여, 탄소나노튜브 기반의 플렉시블 전극은 500번의 굽힘 시험 (bending test)과 6000 번의 충·방전 시험 후에는 초기의 전기 용량값 (67 F․g-1)이 유지되는 결과를 얻었다. In this study, flexible acid treated single walled carbon nanotubes (A-SWCNTs) electrodes were fabricated by using gold coated PET substrate and spray coating technique. The acid-treatment method was conducted to introduce functional groups on the SWCNTs wall, which could improve dispersability of the SWCNTs and its electrochemical property. The electrochemical properties of flexible A-SWCNTs electrode were carried out by cyclic voltammetry(CV), electrochemical impedance were carried out by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and galvanostatic charge/discharge (GCD) cycles. As a results, The specific capacitance value of the unbent A-SWCNTs electrode was 67 F․g-1, which decreased to 63 F․g-1 (94% retention) after 1000 GCD cycles. Interestingly, the specific capacitance of the unbent A-SWCNTs electrode with application of the 1000 GCD cycles was retained even after 500 bending to 30°with 6000 GCD cycles.

Effect of ozone-treated single-walled carbon nanotubes on mechanical properties of carbon fiber-reinforced epoxy composites

박상진,박수진 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In this work, single-walled carbon nanotubes (SWCNTs) surface was successfully modified using the ozone treatment for use as the reinforcement for epoxy polymer matrix composites. The SWCNTs was successfully modified using the ozone dry oxidation method. We focused on the dispersion and interfacial adhesion synergistic effects of ozone-treated SWCNTs (O-SWCNTs) in epoxy matrix and carbon fibers, mechanical of the prepared composites were investigated according to weight ratio of O-SWCNTs. The mechanical properties was calculated by the critical stress intensity factor (KIC) and interlaminar shear strength (ILSS). The morphology was observed by scanning electron microscope (SEM). results show that O-SWCNTs on carbon fibers affects mechanical properties of cabon fiber-reinforced epoxy composites.

아가로스 겔을 이용한 단일벽 탄소나노튜브 분리

우란 ( Lan Yu ),임연수 ( Yun Soo Lim ),한종훈 ( Jong Hun Han ) 한국공업화학회 2011 공업화학 Vol.22 No.3

본 연구는 아가로스 겔을 이용하여 금속성과 반도체성 단일벽 탄소나노튜브의 분리실험을 수행하였다. 아가로스의 농도, 분산제인 SDS (sodium dodecyl sulfate)의 농도, 아가로스 용액의 pH에 따른 단일벽 탄소나노튜브의 분리에 대한 영향을 고찰하였다. UV-vis-NIR 분광 분석으로부터 용액상의 아가로스 농도가 증가함에 따라 원심분리에 의해 추출된 상층부에서 금속성 탄소나노튜브의 비율이 증가하였지만, 분리된 탄소나노튜브의 전체적인 농도는 감소하였다. 분산제인 SDS 농도가 증가할수록 금속성 탄소나노튜브와 SDS와의 화학적 친화성으로 인해 상층부에서 금속성 탄소나노튜브의 비율이 증가하였으며, 아가로스 용액의 pH가 8.2일 때 금속성 탄소나노튜브의 비율이 최대 58.4%까지 증가하였다. The separation of metallic and semiconducting single-wall carbon nanobubes (SWCNTs) by agarose gel method was carried out in this study. The effect of concentration of agarose, SDS (sodium dodecyl sulfate), and pH in the solution on separation behavior was investigated. With increasing the concentration of agarose in the solution, it showed that the ratio of metallic SWCNTs, which was analyzed from UV-vis-NIR spectroscopy, was increased in the solution phase, while the overall concentration of SWCNTs was decreased. With increasing the concentration of SDS, we could observe that the ratio of metallic SWCNTs was increased due to more affinity between SDS molecules and metallic SWCNT. The highest metallic SWCNTs ratio was reached up to 58.4% when the pH of solution was 8.2.

Enhanced Grating Formation Speed and Amplitude of Photorefractive Device Modified with Single-Walled Carbon Nanotubes

오진우,최종완,김낙중 한국고분자학회 2013 Macromolecular Research Vol.21 No.3

We report on a fast and efficient polymeric photorefractive (PR) device by using single-walled carbon nanotubes (SWCNTs) on indium-doped tin oxide (ITO) electrodes. In presence of SWCNTs, the magnitudes of photocurrent,space charge field, and refractive index modulation increased 56.9%, 20.3%, and 22.1%, respectively, due to enhanced charge separation and facilitative charge transport. The PR grating buildup speed of PR device with SWCNTs layers was three-and-a-half times faster than that without SWCNTs layers. The SWCNTs with layer structure provided an efficient electron-transfer matrix.

Role of thermal treatment on the structural behavior of the arc SWCNTs in the purification system process

최상규,이승백 한국물리학회 2009 Current Applied Physics Vol.9 No.3

The role of thermal oxidation before acid treatment and post high-temperature vacuum annealing of single walled carbon nanotube (SWCNTs) was studied by scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analyses and Raman spectroscopy. An efficient procedure is developed for the purification of SWCNTs with minimal damage to the walls and minimal modification in the length of the tubes. SWCNTs are employed in this study, are synthesized by arc-discharge method containing impurity of amorphous carbon, carbon shells, graphitic particles, metallic nanoparticles and metallic nanoparticles encapsulated inside the amorphous carbon or graphite.

Improvement single-wall carbon nanotubes (SWCNTs) based on functionalizing with monomers 2-hydroxyethylmethacryate (HEMA) and N-vinylpyrrolidone (NVP) for pharmaceutical applications as cancer therapy

Fatemeh Abbaszadeh,Omid Moradi,Mehdi Norouzi,Omid Sabzevari 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

The functionalized carbon nanotubes play significant roles in the fields such as preparation of composite materials and biological technologies. This paper explains the covalent functionalization of single-wall carbon nanotubes (SWCNTs) with biomedical important monomers, 2-hydroxyethylmethacryate (HEMA) and N-vinylpyrrolidone (NVP) by chemical grafting of HEMA and PVP monomers via free radical polymerization. To get carboxylic acid functionalized SWCNTs, first the nanotubes were oxidized with a mixture of nitric acid and sulfuric acid (1:3). Then, the binding of HEMA and NVP onto the surface of SWCNTs was performed by chemical functionalization of HEMA, NVP with acid chloride-bound carbon nanotube by esterification reaction. These results were confirmed by FT-IR and SEM. The cell culture experiments conducted for pharmaceutical applications were used as cancer therapy.

Diameter-Selective Synthesis of Single-Walled Carbon Nanotubes on Supported Cobalt Catalysts

Hong Wang,Lian Yang,Pingting Chen,Xiaodong Tang,Jin Yang,Sha Zhu,Yuanyi Liao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8

Supported Co catalysts were prepared by impregnating the support (MgO, SiO2 and Al2O3) with Co(acac)2 solution, and diameter-selective growth of single-walled carbon nanotubes (SWCNTs) by ethanol chemical vapor deposition has been assessed on these Co catalysts. In contrast to Co/SiO2 and Co/Al2O3 catalysts with relatively high surface areas, Co/MgO catalyst with a low surface area demonstrates the best performances in the diameter-selective growth of SWCNTs under an optimal growth condition. Multiple characterizations on catalysts and SWCNTs revealed that Co(acac)2 was absorbed on MgO by ligand exchange and anhydrous solvent CH2Cl2 strengthened the anchoring of Co(acac)2 on the MgO surface, which resulted in well-dispersed Co species upon calcination in air. Under a modest reduction temperature, the reduction of Co oxides provided Co clusters, which were anchored by the unreacted Co ions in the interior of MgO support, leading to the synthesis of SWCNTs with a narrow diameter distribution.