• Journal of the Semiconductor & Display Technology
• /
• v.19 no.1
• /
• pp.73-78
• /
• 2020

There appears lateral capillary force in a hydrophilic flat needle employed for the fabrication of fine organic thin-film stripes, bringing in an increase of the stripe width. It also causes the stripe thickness to increase with increasing coating speed, which is hardly observed in a normal coating process. Through computational fluid dynamics (CFD) simulations, we demonstrate that the lateral capillary flow can be substantially suppressed by increasing the contact angle of the needle end. Based on the simulation results, we have coated the outer surface of the flat needle with a hydrophobic material (polytetrafluoroethylene (PTFE) with the water contact angle of 104°). Using such a hydrophobic needle, we can suppress the lateral capillary flow of an aqueous poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT:PSS) to a great extent, rendering the stripe narrow (63 ㎛ at 30 mm/s). Consequently, the stripe thickness is decreased as the coating speed increases. To demonstrate its applicability to solution-processable organic light-emitting diodes (OLEDs), we have also fabricated OLED with the fine PEDOT: PSS stripe and observed the strong light-emitting stripe with the width of about 68 ㎛.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.112-117
• /
• 2008

Organic-inorganic hybrid solutions were prepared via sol-gel method using glycidoxypropyl trimethoxysilane (GPTMS) and methyl triethoxysilane (MTES) as starting precursors at a molar ratio of 1:1. The photochromic coating solutions were prepared by mixing the solutions of photochromic dye (spiropyran) dissolved in ethylacetate (EA) with the organic-inorganic hybrid solutions. Photochromic films were prepared on polycarbonate substrate by spin coating and cured for 2 h at $100^{\circ}C$. The resulting films exhibited a reversible color change upon irradiation with UV light. The photochromic properties of the films showed that the color-fading speed increases with increasing the EA content in the coating solutions.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.1
• /
• pp.1-5
• /
• 2010

Silver stabilizing layer of coated conductor has been prepared by dip coating method using organic silver complexes containing 10 wt% silver as a starting material. Coated silver complex layer was dried in situ with hot air and converted to crystalline silver by post heat treatment in flowing oxygen atmosphere. A dense continuous silver layer with good surface coverage and proper thickness of 230 nm is obtained by multiple dip coatings and heat treatments. The film heat treated at $500^{\circ}C$ showed good mechanical adhesion and crystallographic property. The interface resistivity between superconducting YBCO layer and silver layer prepared by dip coating was measured as $0.67\;{\times}\;10^{-13}\;{\Omega}m^2$. Additional protecting copper layer with the thickness of $20\;{\mu}m$ was successfully deposited by electroplating. The critical current measured with the specimen prepared by dip coating and sputtering on same quality YBCO layer showed similar value of ~140 A and proved its ability to replace sputtering method for industrial production of coated conductor.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.679-684
• /
• 2002

In this study we performed test to compare and analyze the chloride diffusion properties in concrete according to organic coating materials used at concrete structures widely and inorganic coating materials as eco-materials in recently. The results of study were shown as follow ; 1) Chloride diffusion coefficient was low as low as and that of organic and inorganic painted was lower than non-painting 2) In case of inorganic coating material applied in this study, it should be possible to evaluate the chloride diffusion properties by CTH method. Because presumption value by CTH method is similar with real estimate value by digestion experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.11a
• /
• pp.273-276
• /
• 1995

In this paper, the response characteristics of organic gases were investigated by using quartz crystal microbalance(Q.C.M) with different coating materials. The method for pattern was discussed in order to develope gas sensing system using neural network and pattern recognition. we analyzed the response characteristics by the area of frequency shift, which mean affinities of gases for coating material. The results shows that the Parameter made by the area of frequency shift has possibility to be used for pattern recognition and neural network. we found that each gas had different decrease pattern for coating material.

• Journal of the Korean institute of surface engineering
• /
• v.22 no.3
• /
• pp.109-117
• /
• 1989

The effect of heft treatment on the characteristic properties of insulation layer is studied for two kinds of non-oriented silicon steels, which were insulation-coates with various kinds of inorganic and inorganic-organic complex coating solutions. In addition, how the carbon contained in the insulation layer would affect the carbon content and the magnetic properties of the steel substrates is examined. Lower temperature heat treftment ($480^{\circ}C$ for 0.5hr) is found to render morw favorable surface qualities, wheras higher temperature heat treatment ($790^{\circ}C$ for 2hr) better core loss due to grin growt occurred during the heat treatment. Decarburization of the steel substrate is also found unaffectrd by the presence of carbon in the insulation layer.

• Corrosion Science and Technology
• /
• v.10 no.3
• /
• pp.95-100
• /
• 2011

Protective coatings play an important role in the protection of metallic structures against corrosive environment. The main function of anticorrosive coating is to prevent the materials from corrosive agents, such as water, oxygen and ions. In the study, the corrosion protection properties of urethane and epoxy coating systems were evaluated using EIS methods exposed to the corrosion acceleration test such as Norsok M501, Prohesion and hygrothermal cyclic test. AFM analysis of the coating systems was carried out to monitor the change of roughness of coatings. Urethane coating system was more stable than the epoxy coating under given cyclic conditions. Water uptake into the urethane coatings was less than that into the epoxy coating. The urethane coating system showed better corrosion protection than epoxy coating system based on the changes of the impedance modulus at low frequency region with exposure time. Consequently, the corrosion protection properties of the epoxy and urethane coatings was well correspond with their surface roughness changes and water uptakes.

• Journal of the Korea Furniture Society
• /
• v.26 no.1
• /
• pp.22-30
• /
• 2015

In order to prevent decay, distortion, bending, twist on wood products such as wooden furnitures, variety of coating materials were developed and used so far. The coating materials for wood finishing can be synthesized by natural resource or petroleum. However, these coating materials can cause contamination of indoor air quality due to emission of volatile organic compounds (VOCs). In this study, commercialized coating materials for wood finishing such as varnish, coat, and stain were evaluated on emission characteristics of VOCs. Among the varnish, eco-friendly products had about 15~46% lower TVOC emission ($1,042{\mu}g/m^2h{\sim}3,257{\mu}g/m^2h$, respectively, than typical product ($7,100{\mu}g/m^2h$). Natural resource based coating material showed lowest TVOC emission level. However, one of natural resource based waterborne stain showed higher TVOC emission level because waterborne stain already contained higher amount of natural VOC. Oil-based stain might not be suitable for indoor use on interior wall and furniture due to exceed amount of TVOC. Based on results, natural resource based coat or waterborne stain are recommenced to use on wood products.

• Journal of the Microelectronics and Packaging Society
• /
• v.23 no.4
• /
• pp.79-85
• /
• 2016

It is imperative to find environment-friendly coatings as an alternative to the currently used hexavalent chromate conversion coatings for the purpose of improving the anti-corrosion properties of aluminum alloys. Hence, in this study, the corrosion properties of a trivalent chromate conversion coating solution are analyzed and measured. Because of the presence of multiple components in trivalent chromate conversion coating solutions, it is difficult to control plating, attributed to their mutual organic relationship. It is of significance to determine the concentrations of the components present in these coatings; hence, qualitative and quantitative analysis is required. The coating solution contained not only an environment-friendly component chromium(III), but also zirconium, fluorine, sulfur, and potassium, in the coating film. These metals are confirmed to produce a film with improved corrosion resistance to form a thin layer. The excellent corrosion resistance for the trivalent chromate solution is attributed to various inorganic and organic additives.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.7
• /
• pp.531-536
• /
• 2012

We herein present results of flat and uniform polymer-blended small molecular semiconductor thin films. Which were produced for organic thin film transistors (OTFTs), using a simple pre-metered horizontal dipping process. The organic semiconducting thin films were composed of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-PEN) composite blended with a polymer binder of poly(${\alpha}$-methylstyrene) (PaMS). We show that the pre-metered horizontal-dip-coating(H-dip-coating) process allowed the critical control of the thickness of the blended TIPS-PEN:PaMs thin film. The fabricated OTFTs using the TIPS-PEN:PaMs films exhibited maximum field-effect mobility of $0.22\;cm^2\;V^{-1}\;s^{-1}$. These results demonstrated that H-dip-coated TIPS-PEN:PaMS films show considerable promise for the production of reliable, reproducible, and high-performance OTFTs.