Using first-principles theory, we investigated the adsorption performance of CoN4- CNT towards six small gases including NO, O2, H2, H2S, NH3, and CH4, for exploiting its potential application for chemical gas sensors. The frontier molecular orbital theory was conducted to help understand the conductivity change of the proposed material at the presence of gas molecules. The desorption behavior of gas molecules from CoN4- CNT surface at ambient temperature was analyzed as well to determine its suitability for sensing application. Results show that CoN4- CNT is a promising material for O2 and NH3 sensing due to their desirable adsorption and desorption behaviors while not appropriate for sensing NO due to the poor desorption ability and for sensing CH4 and H2 given the poor adsorption behavior. Our calculation would provide a first insight into the CoN4- embedded effect on the structural and electronic properties of single-walled CNT, and shed light on the application of CoN4- CNT towards sensing of small gases.

A powder-in-sheath rolling method is applied to the fabrication of a carbon nano tube (CNT) reinforced copper composite. A copper tube with outer diameter of 30 mm and wall thickness of 2 mm is used as sheath material. A mixture of pure copper powder and CNTs with a volume content of 3 % is filled in a tube by tap filling and then processed to an 93.3 % reduction using multi-pass rolling after heating for 0.5 h at 400 oC. The specimen is then sintered for 1h at 500 oC. The relative density of the 3 vol%CNT/Cu composite fabricated using powder in sheath rolling is 98 %, while that of the Cu powder compact is 99 %. The microstructure is somewhat heterogeneous in width direction in the composite, but is relatively homogeneous in the Cu powder compact. The hardness distribution is also ununiform in the width direction for the composite. The average hardness of the composites is higher by 8Hv than that of Cu powder compact. The tensile strength of the composite is 280 MPa, which is 20 MPa higher than that of the Cu powder compact. It is concluded that the powder in sheath rolling method is an effective process for fabrication of sound CNT reinforced Cu matrix composites.

Mechanically enhanced supramolecular carbon nanotube (CNT) films were prepared in water by employing the π-electronrich phenyl, naphthalenyl, and pyrenyl end-functionalized polyethylene oxides (PEOs) as supramolecular linkers, followed by vacuum filtration. Among them, the supramolecular CNT film produced by the pyrenyl end-functionalized PEO (PEOPy) exhibited the highest mechanical strength, which was ~ 1.5–2 times higher than that of the CNT films produced using the typical dispersant, Triton X-100, although the functionality of PEO-Py was lower than that prepared using other linkers, and the content of PEO-Py in the CNT films was lower than that obtained using Triton X-100. Fluorescence and UV–Vis spectroscopy demonstrated that the improved mechanical properties of the supramolecular CNT film result from the formation of π–π interactions between the CNT and the pyrene moieties of the PEO-Py linker. Finally, the supramolecular CNT film exhibited a 40–50 dB electromagnetic shielding efficiency through hybridization with silver nanowires.

본 연구에서는 내진성능향상을 목표로 CNT-복합소재로 보강된 콘크리트 구조물의 휨 인장 거동을 다루었다. 다양한 CNT 함유량에 따른 복합소재의 재료적 물성은 수정된 Halpin-Tasi 모델을 적용하여 멀티스케일해석 이론으로부터 도출하였다. 휨인장 시험은 복합소재의 종류, CNT 함유비율, 도포제의 유무, 그리고 보강 방법에 따라서 수행하였다. 변수 실험 결과는 CNT-복합재로 보강된 콘크리트 구조의 향상된 휨인장 거동에 대하여 CNT 함유량과 적절한 도포제의 적용 (부착)의 중요성을 보여주었다.

Multi-walled carbon nanotube (MWCNT)–copper (Cu) composites are successfully fabricated by a combination of a binder-free wet mixing and spark plasma sintering (SPS) process. The SPS is performed under various conditions to investigate optimized processing conditions for minimizing the structural defects of CNTs and densifying the MWCNT–Cu composites. The electrical conductivities of MWCNT–Cu composites are slightly increased for compositions containing up to 1 vol.% CNT and remain above the value for sintered Cu up to 2 vol.% CNT. Uniformly dispersed CNTs in the Cu matrix with clean interfaces between the treated MWCNT and Cu leading to effective electrical transfer from the treated MWCNT to the Cu is believed to be the origin of the improved electrical conductivity of the treated MWCNT–Cu composites. The results indicate the possibility of exploiting CNTs as a contributing reinforcement phase for improving the electrical conductivity and mechanical properties in the Cu matrix composites.

We demonstrated a CNT synaptic transistor by integrating 6,6-phenyl-C61 butyric acid methyl ester(PCBM) molecules as charge storage molecules in a polyimide(PI) dielectric layer with carbon nanotubes(CNTs) for the transistor channel. Specifically, we fabricated and compared three different kinds of CNT-based synaptic transistors: a control device with Al2O3/PI, a single PCBM device with Al2O3/PI:PCBM(0.1 wt%), and a double PCBM device with Al2O3/PI:PCBM(0.1 wt%)/PI:PCBM(0.05 wt%). Statistically, essential device parameters such as Off and On currents, On/Off ratio, device yield, and longterm retention stability for the three kinds of transistor devices were extracted and compared. Notably, the double PCBM device exhibited the most excellent memory transistor behavior. Pulse response properties with postsynaptic dynamic current were also evaluated. Among all of the testing devices, double PCBM device consumed such low power for stand-by and its peak current ratio was so large that the postsynaptic current was also reliably and repeatedly generated. Postsynaptic hole currents through the CNT channel can be generated by electrons trapped in the PCBM molecules and last for a relatively short time(~ hundreds of msec). Under one certain testing configuration, the electrons trapped in the PCBM can also be preserved in a nonvolatile manner for a long-term period. Its integrated platform with extremely low stand-by power should pave a promising road toward next-generation neuromorphic systems, which would emulate the brain power of 20W.

In the present work, we use multiwall carbon nanotubes (MWCNT) as the starting material for the fabrication of sintered carbon steel. A comparison is made with conventionally sintered carbon steel, where graphite is used as the starting material. Milling is performed using a horizontal mill sintered in a vacuum furnace. We analyze the grain size, number of pores, X-ray diffraction patterns, and microstructure. Changes in the physical properties are determined by using the Archimedes method and Vickers hardness measurements. The result shows that the use of MWCNTs instead of graphite significantly reduces the size and volume of the pores as well as the grain size after sintering. The addition of Y2O3.to the Fe-MWCNT samples further inhibits the growth of grains.

최근 대두된 난분해성 미량오염물질은 일반적인 수처리 공법으로는 제거가 잘 되지 않고 수 ng/L 단위로도 수중생태계와 인간에게 독성을 나타내므로 반드시 처리가 필요하다. 따라서 본 연구에서는 CNT (Carbon nanotube)를 이용하여 중공사막을 제조한 후, 그것을 전극으로 사용하여 미량오염물질을 전기화학적으로 산화 제거하였다. SEM, BET, flux, conductivity 결과를 통해 전극의 특성을 분석하였다. BPA(bisphenol A), Sulfamethoxazole(SMX), N,N-Diethyl-metatoluamide(DEET) 3가지 물질을 제거 대상 미량오염물질로 선정하였고 CHM 산화극 내부로 오염물질이 포함된 물을 흘려 보내주었을 때 5분 만에 100%의 제거효율을 보였다.

Thin-film nanocomposite (TFN) reverse osmosis (RO) membranes have drawn keen attention to overcome the limitations in polymeric desalination membranes. However, preparation of TFN-RO membranes using conventional protocol involves problems such as a waste of expensive nanomaterials and inaccurate control of loading amount. In this work, we suggest a new protocol of TFN-RO membranes through pre-adsorption of carbon nanotubes (CNTs) on the support layer using spray coating. SEM images of spray coated supports showed well-dispersed adsorption of CNTs compared with those using conventional method. RO performances of TFN membranes using spray coating were comparable to conventionally prepared membranes. Thus, this new protocol is useful to prepare TFN membranes in terms of cost-efficiency.

This study is based on the screen printing method with heat resistant thin film as base material and development for expansion is proceeding. Therefore, it is convenient to be applicable to the installation and it will be possible to reduce the cost compared with the existing construction such as heat trace by 50% or more. As a result, it is possible to develop and commercialize the market for Polar ship, shipbuilding and offshore plants as it is possible to secure CNT(Carbon Nano Tube) based surface heating element and heating paste composition technology as a heating element material at a cryogenic temperature. It is expected that the efficiency will be great when this method is applied to other industries.

A TiO2/CNT nanohybrid photocatalyst is synthesized via sol-gel route, with titanium (IV) isopropoxide and multi-walled carbon nanotubes (MWCNTs) as the starting materials. The microstructures and phase constitution of the nanohybrid TiO2/CNT (0.005wt%) samples after calcination at 450oC, 550oC and 650oC in air are compared with those of pure TiO2 using field-emission scanning electron microscopy and X-ray diffraction, respectively. In addition, the photocatalytic activity of the nanohybrid is compared with that of pure TiO2 with regard to the degradation of methyl orange under visible light irradiation. The TiO2/CNT composite exhibits a fast grain growth and phase transformation during calcination. The nanocomposite shows enhanced photocatalytic activity under visible light irradiation in comparison to pure TiO2 owing to not only better adsorption capability of CNT but also effective electron transfer between TiO2 and CNTs. However, the high calcination temperature of 650oC, regardless of addition of CNT, causes a decrease in photocatalytic activity because of grain growth and phase transformation to rutile. These results such as fast phase transformation to rutile and effective electron transfer are related to carbon doping into TiO2.

SnO2:CNT thick films for gas sensors were fabricated by screen printing method on alumina substrates and were annealed at 300 oC in air. The nano SnO2 powders were prepared by solution reduction method using tin chloride (SnCl2.2H2O), hydrazine (N2H4) and NaOH. Nano SnO2:CNT sensing materials were prepared by ball-milling for 24h. The weight range of CNT addition on the SnO2 surface was from 0 to 10 %. The structural and morphological properties of these sensing material were investigated using X-ray diffraction and scanning electron microscopy and transmission electron microscope. The structural properties of the SnO2:CNT sensing materials showed a tetragonal phase with (110), (101), and (211) dominant orientations. No XRD peaks corresponding to CNT were observed in the SnO2:CNT powders. The particle size of the SnO2:CNT sensing materials was about 5~10 nm. The sensing characteristics of the SnO2:CNT thick films for 5 ppm H2S gas were investigated by comparing the electrical resistance in air with that in the target gases of each sensor in a test box. The results showed that the maximum sensitivity of the SnO2:CNT gas sensors at room temperature was observed when the CNT concentration was 8wt%.

The characteristics of CNT-Polyamide composites were analyzed, that is, tensile strength, electrical resistivity, and thermal conductivity were measured according to the align length of CNT. There have been researches on the influence of aligned CNT to improve the mechanical and thermal characteristics in different areas including absorption and shielding of electromagnetic wave, thermal distribution or absorption, and high-strength of CNT. The aligned CNTs were synthesized by the ethylene gas with a CVD device preheated at 650℃. CNT-Polyamide composites were produced with the mixing of solution. CNT contents were controlled from 1phr to 50phr in the polyamide-ethanol solution, and blended with the 700W bar-type ultrasonic wave for 60 min.. And then CNT-polyamide were precipitated by CNT-polyamide-etnanol falling into the cold water. After dried 12 hours, CNT-polyamide composite were pressed at 150℃~180℃ with 400kgf to get the thickness of 1mm. As the conclusions, aligned CNT bundles were dispersed by cutting of CNT to the aligned direction because of polyamide properties. Tensile strength and electrical resistivity were improved to the increase of aligned length of CNT. Thermal conductivity was little affected by the align length of CNT.

Thin-film composite membranes (TFCs) have dominated desalination markets for recent decades, but a higher water permeance is still necessary to reduce the energy consumption. Although most researches have focused on the ultrathin active layer of TFCs, the supports should also be considered to further enhance the membrane performances. In this study, TFCs were fabricated on PSf supports containing carbon nanotubes (CNT) by interfacial polymerization. CNT/PSf supports show rougher and more porous surface morphologies than those of bare PSf supports. Because of such surface characteristics, CNT/PSf supports were favorable to increase the roughness and surface area of TFCs. Consequently, TFCs prepared on CNT/PSf nanocomposite supports showed a 41% enhanced water permeance without losing its salt rejection compared to the bare TFCs.

The effect of CNT diameters on properties of CNT-polyamide composites was investigated such as electrical conductivity, tensile strength and thermal conductivity. To get different diameter distributions of CNTs, several portions of Mo and Fe in Mo-Fe/MgO catalysts were synthesized by a combustion method at 600℃. And all CNTs growed at 900℃ with 3 SLM methane and 1 SLM hydrogen for 40min. Four kinds of CNTs with different diameter distributions, such as 1~3nm, 3~7nm, 7~13nm, and 10~30nm, were selected to make CNT-polyamide composites. Each composite was manufactured by a solution mixing using bar-type ultra-sonicator in the CNT portions from 1phr to 50phr. And electrical conductivity, tensile strength, and thermal conductivity were measured. Three properties of CNT-polyamide composite, manufactured with 10nm diameter, were more excellent compared to other composites, with electrical conductivity  Ω at 7phr, thermal conductivity 2.4.W/mK at 40phr, tensile strength 60MPa at 30phr. CNTs with a diameter of 10nm were superior to other diameters for the multi-functional composite such as CNT-polyamide composites.

In this study, titanium(Ti) meshes and porous bodies are employed to synthesize carbon nanotubes(CNTs) using methane(CH4) gas and camphene solution, respectively, by chemical vapor deposition. Camphene is impregnated into Ti porous bodies prior to heating in a furnace. Various microscopic and spectroscopic techniques are utilized to analyze CNTs. It is found that CNTs are more densely and homogeneously populated on the camphene impregnated Ti-porous bodies as compared to CNTs synthesized with methane on Ti-porous bodies. It is elucidated that, when synthesized with methane, few CNTs are formed inside of Ti porous bodies due to methane supply limited by internal structures of Ti porous bodies. Ti-meshes and porous bodies are found to be multi-walled with high degree of structural disorders. These CNTs are expected to be utilized as catalyst supports in catalytic filters and purification systems.