• Journal of Conservation Science
• /
• v.27 no.4
• /
• pp.415-420
• /
• 2011

Urethane coating agent was made up in order to prevent corrosion on metal relics. This urethane coating agent was designed to solve problems linked to gloss and discoloration caused by existing acrylic coating agent which is mainly applied to metal relics. For the purpose, the urethane coating agent was made up which has lower gloss and slight color change. This coating agent formed thinner coating layer with excellent adhesion compared to the existing agent and has outstanding resistance to the surface oxidization of metal relics and water repellent on the surface. In addition, the agent is considered a stable coating agent replacing current acrylic coating agent with showing easy dissolution in organic solvents such as acetone, toluene and xylene with excellent result in reversible reaction.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05b
• /
• pp.156-159
• /
• 2004

TFEMA(2,2,2-trifluoroethylmethacrylate)는 광섬유 코팅제, 발수 발유제, 기능성 페인트, 방오가공제, 고분자의 표면개질제 등의 많은 응용제품에 활용되는 단량체로 그 시장규모가 국내에서 600억원, 전 세계에서 8,000억에 해당하는 고부가가치의 화학원료이다. TFEMA는 현재 산촉매하의 8.$0^{\circ}C$의 고온에서 TFEA(2,2,2-trifluoroethaol)와 MA(methacrylic acid)와의 에스텔화 반응으로 제조된다.(중략)

• Polymer Science and Technology
• /
• v.22 no.3
• /
• pp.256-260
• /
• 2011

• Journal of the Mineralogical Society of Korea
• /
• v.18 no.2
• /
• pp.83-92
• /
• 2005

Dissolution rate of minerals may differ from climates configuration, but weathering rate of feldspars is generally proved to be relatively higher The result of geochemical reaction modeling indicates the acid water of pH 4.5 excluding any other variables, was 2.3 times higher than that in ordinary rain of pH 5.7. This result proved that pH is very important factor in preservation of granite cultural properties. To prevent the weathering of stone cultural properties, weathering characteristics of stones should be studied first and constitution of dry environments, using water repellent or oil coating, isolating water which cause chemical weathering reaction like hydration and oxidization should be considered. Considering the long-term reactions between granite and rain, selection of materials, which can bring neutralization and non-oxidization conditions, are very important in using cleaning agents and biological controls.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.1
• /
• pp.21-28
• /
• 2014

The purpose of this study is to investigate the mechanical properties and carbonation resistance of concretes using lightweight aggregate coated surface finishing materials. To evaluate the mechanical properties and carbonation resistance of concrete, slump, air amount, air-dried unit volume weight, compressive strength, and carbonation depth are tested. In terms of the unit volume weight of concrete, air-dried unit volume weight of concrete using coating lightweight aggregate was measured as $1,739{\sim}1,806kg/m^3$. When using coating aggregate, compressive strength of concrete at 28 days was measured as much as 82.7~95.9% of the compressive strength using non-coating aggregate. It is found that compressive strength tends to decrease with coating lightweight aggregate. However, all concretes using coating lightweight aggregate except O-LWAC satisfied the criteria for 28-day compressive strength suggested in KS. The measurement of carbonation depth when the water-repellent agent was used found that carbonation depth was reduced by as much as 2.6~6.1%. On the other hand, when using polymer waterproof agent, carbonation depth was reduced by as much as 8.6~12.0%. Consequently, to improve carbonation resistance, polymer waterproof agent was more effective than water-repellent agent. In particular, epoxy showed the most outstanding performance.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.196.1-196.1
• /
• 2015

전 세계적으로 환경에 대한 인식이 증대됨에 따라 친환경적인 소재의 개발 연구가 필요한 상황이고, 대표적으로 셀룰로오스를 이용한 종이기판을 활용하는 방안이 새로운 연구화두로 떠오르고 있다. 종이를 기본으로 한 전기전자 회로구성의 가능성을 보기위해 종이 위해 전자회로 구성요소를 형성시켜야 할 필요가 있다. 이를 위해 본 연구팀은 상용 복사 용지위에 마이크로 단위의 패터닝을 구현하는 연구를 진행하였다. 마이크로 패터닝 구현 방법은 다음과 3가지로 요약할 수 있다;1. 리소그래피 공정, 2. 메탈마크스를 사용한 물질 증착, 3. 잉크젯 프린팅. 리소그래피 공정을 위해서 발수처리를 한 종이 위에 실리콘기반 공정과 마찬가지로 레지스트를 코팅하고 노광과 디벨롭, 증착과 리프트오프 과정을 거쳤다. 공정 결과 패터닝이 어느 정도 잘 되는 것을 확인할 수 있었다. 두번째로 상용 메탈마스크를 제작하여 종이 위에 그대로 증착하는 방법을 사용하였다. 이 방법은 액상공정을 요구하지 않기 때문에 발수처리가 필요하지 않고 종이의 기본성질을 그대로 유지 할 수 있다는 장점이 있다. 마지막으로 잉크젯 프린팅 공정은 복사용지를 인쇄할 때 사용하는 간단한 상용프린터를 이용하였다. 이 방법은 앞의 두 공정보다는 다소 패턴 사이즈가 크다는 단점이 있지만 원하는 모양을 자유롭게 패터닝 할 수 있고 그만큼 대량 생산에 용이하다는 장점이 있다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.4
• /
• pp.323-330
• /
• 2009

Efficiency of a fuel cell is determined by the generated water. If water is not removed sufficiently, water will be accumulated at GDL, which causes flooding. Therefore, water control is regarded as a crucial factor to sustain fuel ell performance. In this study, PTFE coating on the surface of carbon paper was carried out to establish optimum process for hydrophobic treatment of GDL. Carbon paper was immersed at different concentrations of nano-sized PTFE coating solution. Their characteristics were analyzed systematically by FE-SEM, water contact angle, cyclic voltamogam, XRD and FT-IR. The quantitative correlation between the amount of coated-PTFE on a carbon paper and concentration of coating solution was carefully investigated. It is suggested that the amount of PTFE-coating on a carbon paper can be managed by means of controling concentration of coating solution.

• Journal of Applied Reliability
• /
• v.17 no.1
• /
• pp.78-82
• /
• 2017

Purpose: The purpose of this study is to evaluate failure characteristic and mechanism of four commercial water-repellent coatings for elevated temperature machinery applications. Method: Thermal degradation was performed for up to 64 thermal cycles. 1 cycle consists of 15 minute holding at 523K under 300rpm revolution and 15 minute-natural cooling. Contact angle was measured and microstructure of the coating layer was observed by using a scanning electron microscope. Results: Four kinds of commercial repellent coating showed hydrophobic or super-hydrophobic property implying that all coatings are suitable for room temperature application. Contact angle of three kinds of commercial coatings decreased rapidly after thermal exposure, while only one specimen having hydrophobic surface showed extremely slow degradation. Conclusion: Observed decrease in contact angle of the coatings were attributed to formation of macro-sized pores and disappearance of micro-protrusion during thermal exposure. Optimum water-repellent coating needs to be selected under the consideration of initial contact angle as sell as service temperature.

• Korean Journal of Materials Research
• /
• v.17 no.11
• /
• pp.569-573
• /
• 2007

The static and dynamic hydrophobicities of the water droplets placed on a hydrophobic surface coated using a fluoroalkylsilanes monolayer with different molecular chain lengths were investigated through direct observation of the actual droplet motion during the sliding process. The surface roughness of both was found to be less than 1 nm. The static contact angles of the coated FAS-3 and FAS-17 were respectively $80^{\circ}$ and $108^{\circ}$ at $150^{\circ}C$, 1 h. The slope of sliding acceleration against the water droplet mass exhibited an inflection point, thus suggesting the switching of the dominant sliding mode from slipping to rolling. While their sliding angles were similar in value, notable differences were exhibited in terms of their sliding behavior. This can be understood as being due to the contribution of the shear stress difference at the interface between the solid surface and water during the sliding process. These results show that the sliding acceleration of the water droplets depends strongly on the balance between gravitational and retentive forces on the hydrophobic surface.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.4
• /
• pp.20-25
• /
• 2020

As nanoscience and nanotechnology advance, techniques for selective pattern growth have attracted significant attention. Silica nanoparticles (NPs) are used as a promising nanomaterials for bio-labeling, bio-imaging, and bio-sensing. In this study, silica NPs were synthesized by a sol-gel process using a modified Stöber method. In addition, the selective pattern growth of silica NPs was achieved by the surface functionalization of the substrate using a micro-contact printing technique of a hydrophobic treatment. The particle size of the as-synthesized silica NPs and morphology of selective pattern growth of silica NPs were characterized by FE-SEM. The contact angle by surface functionalization of the substrate was investigated using a contact angle analyzer. As a result, silica NPs were not observed on the hydrophobic surface of the OTS solution treatment, which was coated by spin coating. In contrast, the silica NPs were well coated on the hydrophilic surface after the KOH solution treatment. FE-SEM confirmed the selective pattern growth of silica NPs on a hydrophilic surface, which was functionalized using the micro-contact printing technique. If the characteristics of the selective pattern growth of silica NPs can be applied to dye-doped silica NPs, they will find applications in the bio imaging, and bio sensing fields.