• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.539-540
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• 2010

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.203-204
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• 2008

Using various surfactants, multi-walled carbon nanotube (MWNT) was dispersed in organic solvent, isopropylalcohol(IPA). To refine the MWNT and give the functional group, MWNT was treated with sulfuric acid/nitric acid(v/v=3/1). The cationic, nonionic and anionic surfactants were used as MWNT dispersion agents in the organic solvent. Dispersion effect of various surfactants was observed by optical microscope and HR-TEM. Surface resistivities of MWNT dispersions were measured after coating on PET film. MWNT was dispersed well by poly vinyl pyrrolidone(PVP), nonionic surfactant.

• Safety and Health at Work
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• 제2권1호
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• pp.65-69
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• 2011

Objectives: Carbon nanotubes are an important new class of technological materials that have numerous novel and useful properties. Multi-walled carbon nanotubes (MWCNTs), which is a nanomaterial, is now in mass production because of its excellent mechanical and electrical properties. Although MWCNTs appear to have great industrial and medical potential, there is little information regarding their toxicological effects on researchers and workers who could be exposed to them by inhalation during the handling of MWCNTs. Methods: The generation of an untangled MWCNT aerosol with a consistent concentration without using surfactants that was designed to be tested in in vivo inhalation toxicity testing was attempted. To do this, MWCNTs were dispersed in deionized water without the addition of any surfactant. To facilitate the dispersion of MWCNTs in deionized water, the water was heated to $40^{\circ}C$, $60^{\circ}C$, and $80^{\circ}C$ depending on the sample with ultrasonic sonication. Then the dispersed MWCNTs were atomized to generate the MWCNT aerosol. After aerosolization of the MWCNTs, the shapes of the NTs were examined by transmission electron microscopy. Results: The aerosolized MWCNTs exhibited an untangled shape and the MWCNT generation rate was about 50 $mg/m^3$. Conclusion: Our method provided sufficient concentration and dispersion of MWNCTs to be used for inhalation toxicity testing.

• Bulletin of the Korean Chemical Society
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• 제27권7호
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• pp.991-994
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• 2006

Herein, insoluble single-walled carbon nanotube (SWNT) was successfully dispersed into water in the presence of a special kind of surfactant-dicetyl phosphate (DCP), subsequently, a SWNT-DCP composite film coated glassy carbon electrode (GCE) was fabricated. The electrochemical behaviors of 6-benzylaminopurine (6-BAP) at the unmodified GCE and SWNT-DCP modified GCE were examined. It is found that the SWNT-DCP modified GCE remarkably enhances the oxidation peak current of 6-BAP, indicating great potential in the determination of trace level of 6-BAP. Finally, a sensitive and simple voltammetric method with a good linear relationship in the range of ${\times}5.0\;\;10^{-8}\sim 2.5\;{\times}\;10^{-6}$ mol/L, was developed for the determination of 6-BAP. The detection limit is as low as $2.0\;{\times}\;10^{-8}$ mol/L for 3-min accumulation. This newly-proposed method was successfully demonstrated with practical samples.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.153-153
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• 2008

Practical application of single-walled carbon nanotubes (SWCNTs) qualified as a promising material has been limited by either poor dispersion or their insolubility in aqueous or organic media due to formation of bundling by relatively high surface energy. Thus, major attention to overcome this issue has been paid at surface modification of CNTs by functionalization, but this introduces defects to the sidewall of CNTs, consequently perturbing the inherent electronic and optical properties. Therefore, using surfactants is a general approach to disperse SWCNTs with lower damages by which bundled nanotubes could be dispersed up to the level of individuals or small bundles. Here, we have investigated various surfactants for their efficiency in dissolving purified SWCNTs produced by arc discharge in deionized water. To compare the surfactants respectively, we have determined the least amount of each surfactant to suspend the nanotubes under optimized experimental conditions(CNT amount, sonication power, and centrifugation speed, etc.) set on the basis of the most common surfactant (sodium dodecyl sulfate, SDS) and discussed the qualitative and quantitative characterization of SWCNT dispersions by UV-Vis absorption spectroscopy. Quantitative aspect about nanotube dispersion was that in particular N-methyl-2-pyrrolidone (NMP) and sodium dodecylbenzene sulfonate (NaDDBS) were found to be effective in dispersing individual tubes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.417-417
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• 2009

Although a transparent conductive film (TCF) belongs to essential supporting materials for many device applications such as touch screens, flat panel displays, and sensors, a conventional transparent conductive material, indium-tin oxide (ITO), suffers from considerable drawback because the price of indium has soared since 2001. Despite a recent falloff, a demand of ITO is expected to increase sharply in the future due to the trend of flat panel display technologies toward flexible, paper-like features. There have been recently extensive studies to replace ITO with new materials, in particular, carbon nanotubes (CNTs) since CNTs possess excellent properties such as flexibility, electrical conductivity, optical transparency, mechanical strength, etc., which are prerequisite to TCFs. This study fabricated TCFs with single-walled carbon nanotubes (SWCNTs) produced by arc discharge. The SWCNTs were dispersed in water with a surfactant of sodium dodecyl benzene sulfonate (NaDDBS) under sonication. Carbon black and fullerene nanoparticles were added to the SWCNT-dispersed solution to enhance contact resistance between CNTs. TCFs were manufactured by a filtration and transfer method. TCFs added with carbon black and fullerene nanoparticles were characterized by scanning electron microscopy (SEM), UV-vis spectroscopy (optical transmittance), and four-point probe measurement (sheet resistance).

• 설비공학논문집
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• 제19권3호
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• pp.275-283
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• 2007

An experimental study was conducted to investigate the effect of the morphology of CNT (Carbon Nanotube) on the thermal conductivity of suspensions. The effective thermal conductivities of the samples were measured using a steady-state cut bar apparatus method. Enhancements based on the thermal conductivity of the base fluid are presented as functions of both the volume fraction and the temperature. Although functionalized SWNT (Single-Walled Carbon Nanotube) produced more stable and homogeneous suspensions, the addition of small amounts of surfactant to suspensions of 'as produced' SWNT demonstrated a greater increase in effective thermal conductivity than functionalized SWNT alone. The effective thermal conductivity enhancement corresponding to 1.0% by volume approached 10%, which was observed to be lower than expected, but more than twice the values, 3.5%, obtained for similar tests conducted using aluminum oxide suspensions. However, for suspensions of MWNT (Multi-Walled Carbon Nanotube), the degree of enhancement was measured to be approximately 37%. It was postulated that the effect of clustering, resulting from the multiple heat-flow passages constituted by interconnecting neighboring CNT clusters, played an important role in significant enhancement of effective thermal conductivity.

• 폴리머
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• 제36권5호
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• pp.579-585
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• 2012

고분자 발포체에 전도성을 부여하기 위하여 고내상 에멀젼 중합법을 활용하여 폴리스티렌/탄소나노튜브 미세기공 발포체를 제조하였다. 본 연구에서는 고내상 에멀젼의 안정성과 중합된 미세기공 발포체의 전기 전도도를 향상시키기 위하여 탄소나노튜브의 개질, 계면활성제의 함량 및 분산 시간에 따른 영향을 고찰하였다. 탄소나노튜브는 분산이 용이하도록, 분산상인 수상에는 산처리 및 계면활성제로 분산하여 사용하였고 연속상인 유상에는 유기 작용기로 표면 개질하여 사용하였다. 탄소나노튜브의 분산성은 제조한 발포체의 전기 전도도 차이로 확인할 수 있었다. 계면활성제로 분산한 미처리 탄소나노튜브를 수상에 첨가한 경우 전기 전도도 향상에는 효과적이었지만 약간 수축된 형상의 발포체가 제조되었다. 유기 개질한 탄소나노튜브를 유상에 첨가한 경우 안정한 발포체를 얻을 수 있었으나 전기 전도도 향상에는 한계가 있었다.

• Composites Research
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• 제29권5호
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• pp.269-275
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• 2016

Multiscale hybrid composites, which consist of polymeric resins, microscale fibers and nanoscale reinforcements, have drawn significant attention in the field of advanced, high-performance materials. Despite their advantages, multiscale hybrid composites show challenges associated with nanomaterial dispersion, viscosity, interfacial bonding and load transfer, and orientation control. In this paper, carbon nanotube(CNT)/carbon fiber(CF)/polycarbonate(PC) multiscale hybrid composite were fabricated by a solution process to overcome the difficulties associated with controlling the melt viscosity of thermoplastic resins. The dependence of CNT loading was studied by varying the method to add CNTs, i.e., impregnation of CF with CNT/PC/solvent solution and impregnation of CNT-coated CF with PC/solvent solution. In addition, hybrid composites were fabricated through surfactant-aided CNT dispersion followed by vacuum filtration. The morphologies of the surfaces of hybrid composites, as analyzed by scanning electron microscopy, revealed the quality of PC impregnation depends on the processing method. Dynamic mechanical analysis was performed to evaluate their mechanical performance. It was analyzed that if the position of the value of tan ${\delta}$ is closer to the ideal line, the adhesion between polymer and carbon fiber is stronger. The effect of mechanical interlocking has a great influence on the dynamic mechanical properties of the composites with CNT-coated CF, which indicates that coating CF with CNTs is a suitable method to fabricate CNT/CF/PC hybrid composites.

• 폴리머
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• 제36권3호
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• pp.364-371
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• 2012

폴리스티렌(PS)/단일벽 탄소나노튜브(SWCNT) 나노복합재료를 라텍스 기술로 제조하여 계면활성제(SDS) 첨가에 따른 SWCNT의 분산 정도와 나노복합재료의 유변학적, 전기적 물성을 고찰하였다. 나노복합재료는 단분산 PS 입자에 SDS를 첨가한 SWCNT 분산액을 혼합한 후 동결건조하여 제조하였다. SDS 함량이 증가함에 따라 나노튜브의 분산성이 향상되어 나노복합재료의 저장 탄성률과 복소 점도는 증가하지만, 지나치게 증가시킨 경우에는 저분자량의 SDS로 인해 감소하는 결과를 보여주었다. 전기 전도도는 SDS를 첨가함에 따라 급격히 향상된 후 큰 변화를 보이지 않았다. 이는 나노튜브의 분산성 향상에 의한 전기 전도도 증가와 SDS 도포에 의한 SWCNT의 전기 전도도 저하의 경쟁에 의한 것으로 추론된다. SDS를 SWCNT 함량의 2배로 첨가한 경우가 나노복합재료의 전기 전도도 및 사용 물성 향상에 최적 조건이었다. 이 경우 전도성을 부여하는 SWCNT의 임계 함량은 1 wt% 이하에서 나타났다.