• 한국전기전자재료학회논문지
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• 제28권7호
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• pp.462-466
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• 2015

In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.201-202
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• 2021

Currently, the domestic construction industry is trying to expand the range of building materials due to overload of growth. In particular, several studies are being conducted to make up for the weakness of building materials by solving problems such as reduction of tensile strength and brittle behavior of concrete. Among them, efforts to maximize the use of carbon nanotubes (CNT) that has excellent mechanical and electrical conductivity properties are continuing. However, CNT is hydrophobic and have a strong Van der Waals force between particles, making it difficult to obtain an effective dispersion state. Therefore, in this study, various kinds of surfactants like DOC (Sodium Deoxycholate), PVP (Polyvinylpyrrolidone), and PCE (Polycarboxylate ester) were added to improve the dispersibility of CNT, and analyzed the changes in the properties of the cement paste mixed with them.

• 접착 및 계면
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• 제4권4호
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• pp.22-27
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• 2003

탄소나노튜브(CNT)의 분산성을 개선하기 위하여 $HNO_3$와 $H_2SO_4$를 사용하여 표면을 개질하였고, 적외선 분광법(FT-IR)과 산-염기 적정법을 통하여 CNT의 표면에 카르복실산이 도입된 것을 확인하였다. CNT의 분산성을 확인하기 위하여 초음파를 이용하여 톨루엔, 디메틸포름아마이드 (DMF) 및 N-메틸피롤리돈(NMP) 등의 유기용매에 개질 전(rCNT) 및 개질 후(mCNT)를 각각 분산시키고, 실시간 광학현미경(real-time video microscope)으로 분산거동을 관찰하였다. rCNT에 비해 mCNT가 극성이 큰 DMF 및 NMP 용매에 분산이 잘 되었으며 비극성인 톨루엔에는 분산성이 나쁨을 알 수 있었다. 또한, DMF에 CNT를 분산시킨 후, 폴리메틸메타크릴레이트(PMMA)를 용해시키고 이를 필름으로 제조한 후 주사전자현미경(SEM)을 통하여 분산형태를 관찰한 결과 mCNT의 분산성이 우수하였다.

• Carbon letters
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• 제28권
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• pp.16-23
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• 2018

A novel, unique, and effective method for carbon nanotube (CNT) dispersion by the free arc stimulation is proposed. CNTs are introduced as an aerogel into the air space via the dispersion method and can be utilized as a solution by adding it to solvents. The volume of the original generated CNT aerogel with a high-volume expansion ratio displays a performance two orders of magnitudes better than that of raw CNTs, which is considered a powerful characterization of the dispersion effect. The CNT aerogel, which was observed by scanning electron microscopy also showed a satisfactory dispersion morphology. Its structure and properties were tested before and after dispersion by Raman spectroscopy and great consistency was observed, which proved that the CNTs were undamaged. This approach may greatly promote the large-scale application of CNTs.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.291-292
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• 2014

최근 CNT의 우수한 물리적 성질을 고분자 복합재료의 필러 등으로 이용하고자, CNT를 용액 중에 고분산 시키는 방법에 관한 연구가 많이 이루어지고 있다. 본 연구에서는 용액 중 플라즈마에 의한 방법에 의해 매우 저 농도의 산용액 중에서 CNT표면에 친수화 작용기를 수식하는데 성공하였으며, 이로 인하여 CNT가 순수 중에서 장시간 분산상태를 유지할 수 있음을 확인 할 수 있었다.

• Macromolecular Research
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• 제15권4호
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• pp.357-362
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• 2007

Polyimide/carbon nanotube (CNT) composite films, for potential use in high performance microelectronics and aerospace applications, were prepared by mixing a polyisoimide (PII) solution and a CNT suspension in NMP, followed by casting, evaporation and thermal imidization. The CNTs were modified by a nitric acid treatment to improve the thermal and electrical properties, as well as to provide good dispersion of the CNTs in a polymer matrix. The formation of functional groups on the modified CNT was confirmed by Raman spectroscopy. Scanning electron microscopy revealed the modified CNTs to be well dispersed in the polyimide matrix, with a uniform diameter of ca. 50 nm. The thermal stability of the films containing the CNTs was improved due to the enhanced interfacial interaction and good dispersion between the polyimide matrix and modified CNTs. In addition, the thermal expansion coefficient of the composites films was slightly decreased, but the dielectric constants increased linearly with increasing CNT content.

• Tribology and Lubricants
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• 제36권6호
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• pp.315-319
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• 2020

In various fields, several studies based on carbon nanotubes (CNTs) have been conducted. The results of previous studies, wherein CNT coatings have been incorporated as solid lubricants, demonstrate that the friction and wear characteristics of CNT coatings can be improved through the absorption/dispersion of the contact pressure by controlling the stiffness of the nanomesh structure comprising CNT strands. In this study, the friction and wear characteristics of the following are compared: CNT coating formed by spin coating of CNT solution, compressed CNT coating, and compressed/heated CNT coating (wherein CNT strands are squeezed through compression and/or heating). It is observed that the friction coefficient of the CNT coating having the largest number of voids between the CNT strands is significantly lower than those of the compressed CNT coating and the compressed/heated CNT coating. The wear tracks of the compressed CNT coating and the compressed/heated CNT coating indicate that some parts become torn or adhere into a lump. However, in the case of the CNT coating, a smooth wear surface is formed by rubbing. Furthermore, as the void space between the squeezed and adhered CNT strands decreases, the resistance to structural deformation increases, thereby resulting in an increased frictional force and a wear pattern that becomes torn or forms a lump. Hence, the results obtained from this study corroborate that the friction and wear characteristics of CNT coatings can be enhanced through the absorption/dispersion of the contact pressure by controlling the stiffness of the nanomesh structure of CNT coatings.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.185-186
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• 2008

Use of the carbon nanotube is superior to general powder state materials of dispersion property. Because its ratio of diameter and length(aspect ratio) is very large, it has been known as a type of ideal nano-reinforcement composite. It used solution mixing method for specimen fabrication. To research dispersion property, we used FE-SEM(Field Emission Scanning Electron Microscope) and AFM(Atomic Force Microscope). As a result, this tendency confirms new conductivity network in which the carbon nanotube between carbon black constitute molecules shows a bond by similar constructive property.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.455-456
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• 2007

Optically transparent, highly conductive coating have been major theme of thin film science efforts for some years. In this work, t-MWNT(thin Multi-walled Carbon Nanotubes) are acid treated, then the stable dispersion of t-MWNTs in polar solvent such as alcohols, was achieved by sonication. The transparent conducting films are prepared using the one component solution of t-MWNT/epoxy binder via spray coating on glass substrate. The characterization of acid treated t-MWNTs was performed by Raman spectrometer. The opto-electrical properties of conducting films are analyzed by the binder concentration, and the effect of co-solvent on the compatibility and dispersibility of one component t-MWNT/epoxy binder solutions are discussed.