• Korean Chemical Engineering Research
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• 제47권3호
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• pp.316-320
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• 2009

폴리카보네이트(polycarbonate)는 가볍고, 내충격성 및 가공성이 우수하여 광학기기의 렌즈 및 각종 건축물의 투명 소재 등에 유리의 대체품으로서 널리 이용되고 있으나 낮은 표면경도를 가지고 있어 유통 또는 사용시의 접촉으로 인하여 제품에 손상을 줄 염려가 있다. 따라서 본 연구에서는 폴리카보네이트 필름에 아크릴레이트 올리고머, 모노머, 용매, 염료, 실리콘 아크릴레이트, 그리고 광개시제 등을 다양한 함량비율에 따라 혼합한 코팅용액을 제조하고, 구성 성분의 비율에 따른 폴리카보네이트 필름의 표면 경도, 접착력, 그리고 투과율의 변화를 실험하였다. 그 결과 최대 연필 경도가 2H이고, 접착력과 가시광선 투과율이 우수한 코팅용액의 조성을 얻었다. 색상코팅 실험 결과, 기존 산화물 증착에 의해 구현하던 색상을 본 실험에서 제조한 코팅 용액을 사용하여 거의 대부분 구현할 수 있었으며, 이를 바탕으로 색상 윈도우 렌즈를 제작한 결과, 매우 깨끗하고 균일한 색상과 표면을 가졌다.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.754-761
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• 2017

알코올에 분산된 콜로이드 실리카를 아크릴 단량체인 pentaerythritol triacrylate (PETA)와 혼합시킴에 의해 UV 경화형 친수성 코팅 용액을 제조하였다. 또한 이 친수성 코팅 용액을 PC 기재 위에 스핀코팅 시킨 후 10 min 동안 UV 경화시킴에 의해 친수성 코팅 도막이 제조되었다. 이 과정 중 코팅 용액 중의 콜로이드 실리카 양을 10~50 g으로 변화시켜 코팅 도막의 친수성에 미치는 영향을 살펴보았다. 그 결과 코팅 용액 중의 콜로이드 실리카 양은 코팅 도막의 친수성에 큰 영향을 미치며, 콜로이드 실리카 양이 30 g인 경우에 $37^{\circ}$의 가장 낮은 접촉각과 H의 우수한 연필경도를 나타내었다.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.14-17
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• 2007

The slot-die coating & calcination process was adopted to fabricate the long YBCO precursor films on the buffered metal tape for the $2^{nd}$ generation coated conductors. To obtain the smooth and crack-free surface of long YBCO precursor films, the parameters of slot-die coating and the process variables of calcination step must be optimized simultaneously in reel-to-reel method. Among the parameter of slot-die coating process, the viscosities of the precursor solution was controlled from 60cP to 200cP to obtain the thicker films from on single coating. The slot-die gap, the injection rate of precursor solution, the moving speed of buffered metal tape etc. are controlled lot the full coverage and smooth surface of YBCO precursor films. The slot-die coated films are moved through the tube furnace with predetermined heating profiles in humid oxygen ambient The YBCO precursor films was identifed with $Y_2O_3,\;BaF_2$, and CuO phase by XRD and consisted of fine grains of about 20nm size observed by FE-SEM. The YBCO films show the critical current density over $MA/cm^2$ using the precursor films formed by the continuous slot-die coating & calcination process.

• 한국재료학회지
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• 제22권8호
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• pp.416-420
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• 2012

Recently nanoscience and nanotechnology have been studied intensively, and many plants, insects, and animals in nature have been found to have nanostructures in their bodies. Among them, lotus leaves have a unique nanostructure and microstructure in combination and show superhydrophobicity and a self-cleaning function to wipe and clean impurities on their surfaces. Coating films with combined nanostructures and microstructures resembling those of lotus leaves may also have superhydrophobicity and self-cleaning functions; as a result, they could be used in various applications, such as in outfits, tents, building walls, or exterior surfaces of transportation vehicles like cars, ships, or airplanes. In this study, coating films were prepared by dip coating method using polypropylene polymers dissolved in a mixture of solvent, xylene and non-solvent, methylethylketon, and ethanol. Additionally, attempts were made to prepare nanostructures on top of microstructures by coating with the same coating solution with an addition of carbon nanotubes, or by applying a carbon nanotube over-coat on polymer coating films. Coating films prepared without carbon nanotubes were found to have superhydrophobicity, with a water contact angle of $152^{\circ}$ and sliding angle less than $2^{\circ}$. Coating films prepared with carbon nanotubes were also found to have a similar degree of superhydrophobicity, with a water contact angle of 150 degrees and a sliding angle of 3 degrees.

• 한국세라믹학회지
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• 제34권7호
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• pp.774-780
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• 1997

Porous low reflective coating films of SiO2.ZrO2 system were prepared from the mixed alkoxide solutions of Zr(O-nC3H7)4 and partially prehydrolyzed TEOS by the sol-gel method using the dip-coating technique. In the case of 90SiO2.10ZrO2 porous coating films with HCl and H2O content was 0.3 mole and 4 mole, 378 m2/g of the specific surface area, 0.254 cm3/g of total pore volume, 30-50$\AA$ of average pore diameter. The transmittance of 90SiO2.10ZrO2 porous coated films was 95.38% at the wavelength of 550 nm, compared with the parent glass, the transmittance was increased with 4.38%.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.1014-1019
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• 2006

The influence of the number of solution coatings on the densification of the PZT thick films was studied. PZT powder and PZT precursor solution was prepared by a sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The powder and solution of composition were (A) PZT(80/20)/PZT(20/80), (B) PZT(70/30)/PZT(30/70) and (C) PZT(60/40)/PZT(40/60), (D) PZT(52/48)/PT. The coating and drying procedure was repeated 4 times. And then the PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 moth and the number of coating was repeated from 0 to 6. The porosity of the thick films was decreased with increasing the number of coatings and the PZT thick films with 6-times coated showed the dense microstructure and thickness of about $60{\mu}m$. A grain size was increased with increasing the coating number. All PZT thick films showed the typical XRD patterns of a typical perovskite polycrystalline structure. The relative dielectric constant of PZT thick films was improved 30-100% as the number of coatings.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.418-422
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• 2005

By introducing spin-coating method to the evaporation induced self-assembly (EISA) process, a simple and reproducible route in controlling the mesophase of silica thin films has been developed for the first time in this work. When a comparatively solvent-rich Si-sol (The atomic ratio of TEOS : F127 : HCl : $H_2O$ : EtOH = 1 : 0.006 : 0.2 : 9.2 : 30) was used as coating solution, the mesophase of resultant silica films was selectively controlled by adjusting the spin-on speed. The cubic mesophase has been obtained from the coating at a low rpm, such as 600 rpm, while the 2-D hexagonal mesophase is formed at a high rpm, such as 2,500 rpm. At a medium coating speed, a mixture of cubic and hexagonal mesophase has been found in the fabricated films. The present results confirm that the evaporation rate of volatile components at initial step is critical for the determination of mesopore structures during the EISA process.

• 한국가구학회지
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• 제12권1호
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• pp.11-20
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• 2001

To investigate weathering and surface characteristics of coating film on lumbers coated with Hwangchil(varnish of Dendropanax morbifera), we carried out to investigate the resistance against discoloration, value of crack and surface characteristics of coating films on seven domestic lumbers and those of four introduced tropical lumbers. There was investigated to evaluate the properties of coating films by the varnish of Dendropanax morbifera. There was insignificant correlations between the hardness and moisture contents of each lumber treated by the varnish. There was no significant correlations between the thickness of coating film and the hardness, either. Although we investigated 11 wood species, we found only three species as resistance wood species against discoloration; Diospysos spp., Abies holophylla and Ulmus davidiana. The crack of coaing films was the largest on Zelkova serrata followed by Juglans sinensis, Cercidiphum japonicum, Tectona grands, Ulmus davidiana, Guibourtia tessmannii, Diospysos spp. and Dalbergia latifolia. However, there was no crack of coating films on the lumbers of Juniperus rigida, Prunus serrulata var. spontanea and Abies holophylla. The crack of coating film showed positive correlations with the thickness of coating film and hardness. The surface characteristics of the coating films evaluated on the basis of $R_{a}$ values indicated the lumbers of Ulmus davidiana($0.14{\;}{\mu}m$), Juniperus rigida($0.1 5{\;}{\mu}m$), Guibourtia tessmannii($0.19{\;}{\mu}m$), Dalvergia latifolia($0.20{\;}{\mu}m$) and Diospysos spp.($0.20{\;}{\mu}m$), Cercidiphum japonicum($0.24{\;}{\mu}m$) as good species while there was insignificant differences between softwoods and hardwoods. Tectona grands, Prunus serrulata var. spontanea and Abies holophylla showed rough surface with $1.53~2.63{\;}{\mu}m$ of $R_a$ values. The four kinds of rough indices($R_a,{\;}R_z,{\;}R_{max}{\;}and{\;}R_q$) showed very low correlations with moisture contents with the correlation coefficients. The $R_a{\;}and{\;}R_{max}$ also showed slight relationship with hardness.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.247-252
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• 2017

실란커플링제인 아미노실란을 15~20 nm의 직경을 갖는 콜로이드 실리카와 반응시킴에 의해 친수성 코팅 용액을 제조하였다. 또한 친수성 코팅 용액을 폴리카보네이트 기재 위에 담금 코팅 시킨 후 $120^{\circ}C$에서 열경화 시킴에 의해 친수성 코팅 도막이 제조되었다. 이 과정 중 아미노실란의 종류 변화가 코팅 도막의 물성에 미치는 영향을 연구하였다. 그 결과 아미노실란으로서 3-aminopropyltriethoxysilane (APTES)을 사용하여 제조된 코팅 도막은 $25{\sim}44^{\circ}$의 접촉각과 B의 좋지 못한 연필경도를 나타내었다. 반면에 아미노실란으로서 3-aminopropyltrimethoxysilane (APTMS)을 사용하여 제조된 코팅 도막은 $26{\sim}37^{\circ}$의 접촉각과 2H의 우수한 연필경도를 나타내었다.

• Tribology and Lubricants
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• 제20권5호
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• pp.237-244
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• 2004

Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.