• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.636-641
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• 2000

The purpose of this study is assessing the characteristics of surface aging and recovery of hydrophobicity for silicone rubber which takes a great interest as outdoor insulation recently subjected to the combined stressed of salt fog and AC power. The methods for assessing are contact angle ATR-FRIR, AFM and XRD. In addition salt fog method is adopted as the artificial contamination experiment and AC power is applied 24 hour on and 24 hour off repeatedly for 5 cycles. The results suggest that degraded surface was more rough than virgin but was restored water repellency through the off cycle. It was due to not only the formation of fractal surface but also maintenance of hydrophobic surface by diffusion of low molecular oil. Although surface recovers initial hydropohbicity there are possibilities of decreasing electrical performance due to irreversable changes such as depolymerization of surface and loss of filler particles. This fact is confirmed by surface conductivity measurement showing that the degradation is significant and the recovery of hydrophobicity is imperfect as the energized cycle increases.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.1020-1025
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• 2012

In this study, we fabricated the superhydrophobic and super-water-repellent surface with the micro/nano scale structures using simple conventional silicon wet-etching technique and the black silicon method by deep reactive ion etching. These fabrication methods are simple but very effective. Also we reported the droplet impact experimental results on the micro/nano-scaled surface. There are two representative impact behaviors as "rebound" and "fragmentation". We found the transition Weber number between "rebound" and "fragmentation" statements, experimentally. Additionally, we concerned about the dimensionless spreading diameters for our super-water-repellent surface. The novel characterization method was introduced for analysis including the "fragmentation" region. As a result, our super-water-repellent surface with the micro/nano-scaled structures shows the different impact behaviors compared with a reference smooth surface, by some meaningful experiments.

• Corrosion Science and Technology
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• v.20 no.5
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• pp.256-265
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• 2021

Titanium is applied in various industries due to its valuable properties and abundant reserves. Generally, if a highly uniform oxide structure and a high-density oxide film is formed on the surface through anodization treatment, the utility value such as color appearance and corrosion inhibition efficiency is further increased. The objective of this study was to determine improvement of water-repellent property by controlling titanium oxide parameters such as pore size and inter-pore distance to improve corrosion resistance. Oxide film structures of different shapes were prepared by controlling the anodization processing time and voltage. These oxide structures were then analyzed using a Field Emission Scanning Electron Microscope (FE-SEM). Afterwards, a Self-Assembled Monolayer (SAM) coating was performed for the oxide structure. The contact angle was measured to determine the relationship between the shape of the oxide film and the water-repellency. The smaller the solid fraction of the surface, the higher the water-repellent effect. The surface with excellent hydrophobic properties showed improved corrosion resistance. Such water-repellent surface has various applications. It is not only useful for corrosion prevention, but also useful for self-cleaning. In addition, a hydrophobic titanium may open up a new world of biomaterials to remove bacteria from the surface.

• Journal of Surface Science and Engineering
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• v.54 no.2
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• pp.90-95
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• 2021

Surface modification technique enabling the control of condensation provides various benefit in various engineering systems, such as heat transfer, desalination, power plants, and so on. In this study, lubricant oil-impregnation into Teflon-coated nanoporous anodic oxide layer of aluminum to enhance a de-wetting and mobility of water droplet on surface. Due to the surface treatment improving water-repellency, the condensation mode is changed to dropwise, thus the frequency of sliding condensed water droplet on surface is increased. For these reasons, the surface of oil-impregnated Teflon-coated nanoporous anodic aluminum oxide shows significantly enhanced condensation heat transfer compared to bare aluminum surface. In addition, the porosity of anodic aluminum oxide affected the mobility of water droplet even with oil-impregnation and Teflon-coating, indicating that the optimization of porous structure of anodic oxide is required for maximizing the condensation heat transfer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.63-64
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• 2023

In order to reduce the high absorption ratio of spent coffee grounds, this study examined the compressive strength and absorption ratio of mortar replacing coated spent coffee grounds according to the type of water repellent. In order to examine this, as the water repellent used, a silane-based water repellent (fluorine-based water repellent) and an acrylic-based water repellent, which are film-type water repellents, and a silane/siloxane-based water repellent, which are penetration-type water repellents, were used. The spent coffee grounds were coated with each of three water repellents, and mortar was prepared by mixing cement and fine aggregate. As a result of the experiment, the compressive strength and absorption ratio of the mortar replaced with coated spent coffee grounds coated with the film-type water repellent were superior to the penetration-type water repellent. Therefore, in order to reduce the high absorption ratio of spent coffee grounds, a suitable water repellent is a film-type water repellent. Among them, it is judged that the acrylic type has excellent water repellency and is suitable.

• Advances in nano research
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• v.15 no.4
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• pp.329-337
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• 2023

Wearing the right sportswear is one of the essential points in exercising, which is mainly neglected. Sportswear should be suitable for the ambient temperature and not cause more heat or cold in the athlete's body. On the other hand, increased sweating and blood circulation during exercise should not cause fatigue or heatstroke in the athlete. Nanotechnology has grown significantly in the field of producing more efficient equipment in the field of sports. The increase in demand in sports for complete sports equipment has revealed the necessity of using the highest quality materials in this sector. In the world of championship sports, a minor change in equipment can lead to significant changes in causing failure and victory. Since the sole is the most critical part of sports shoes, with the introduction of nanotechnology and nanocomposites, it is possible to help athletes rush and increase their sense of calm and satisfaction. Using nanocomposites in the soles of shoes can improve some of their characteristics, prevent the smell and sweat of shoes, and induce water repellency in these shoes. In this research, titanium dioxide (TiO₂) nanocomposite, along with cellulose, has been used to create antibacterial and hydrophobic properties in the soles of sports shoes. The synthesized nanocomposite has been synthesized using the least amount of chemicals, which shows this method's easy and cost-effective synthesis.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.607-614
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• 2015

Generally surface finishing of building is done with water paint that performs basic water repellency and resisting. When painting the exterior of the building with water paint, application method is easy and inexpensive and it has the advantage of building maintenance. But surface finishing of water paint is easy to discolored or aging due to ultraviolet light so the effect is not satisfying than expected. Therefore this study is to analyze durability of water-repellent paints mixed with water-repellents as outer surface finishing materials, and evaluate its feasibility. Color change and color different due to the accelerated time were tested, and the feasibility was evaluated based on the test results. The experimental results of color different, brightness different and chromaticity suggested that water-repellent paints mixed with water-repellents were suitable for finishing materials. Considering overall general durability performances, stable mixing ratios were 2, 5, and 8%.

• Korean Journal of Human Ecology
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• v.18 no.1
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• pp.145-155
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• 2009

The purpose of this study is to examine the university students' awareness and attitudes on functional clothing materials, and to explore the effects of subjects' characteristics on the relationship between their attitudes to and images of the functional clothing materials. A total of 500 questionnaires were distributed to university students and 409 of which were used in data analysis. The data were statistically analyzed by frequency, factor analysis, reliability analysis, correlation analysis, t-test, ANOVA. The results were as follows: students thought that the first and foremost 'function' of functional clothing materials is their light-weight. The functions that consumers practically demanded are water-repellency and high absorbency & quick drying. It showed that students have an image that functional clothing materials have special, good and satisfactory qualities. Goretex and Coolmax were the most selected as brands of functional clothing materials which students knew. Attitudes to functional clothing materials revealed positively in the cognitive, behavioral and affectional attitudes. The attitudes had no significant differences according to sex and their major, but they had significant differences by subjects' amount of allowance, frequency of sports participation and sports ability. In other words, the more amount of allowance they get, the more frequently students do exercise, and the higher sports ability they have, the more positive attitude they have. The study says, in conclusion, that their conception of functional clothing materials has positive relations with their attitudes toward them.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.60-60
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• 2012

최근 들어서 소비성향의 고급화 추세와 고기능성 및 쾌적성의 추구는 발수성의 개발로 이어져왔다. Polyester, Nylon 등 다양한 합성섬유소재의 발전으로 발수기능이 상품가치의 중요한 요소로 자리잡고 있다. 더 나아가 표면과 이면이 서로 다른 특성을 가지도록 유도하여 편면기능성을 부여하는 가공을 응용한다면 더욱 더 고부가가치를 기대할 수 있다. 본 연구에서는 불소계로 발수 처리된 Polyester직물 및 Nylon/PU 혼방직물에 저온 플라즈마를 출력 50W, 1, 3, 5, 7 분 처리하여 편발수성을 검토하였다. 불소계 발수제로 코팅처리한 Polyester직물의 경우 5분간 Plasma처리하면 접촉각이 미처리 시료의 $149^{\circ}$에서 처리 후, 앞면 $71.56^{\circ}$, 뒷면 $126.94^{\circ}$,Nylon/PU 혼방직물의 경우에는 $155.3^{\circ}$에서 앞면 $63.24^{\circ}$, 뒷면 $139.26^{\circ}$로 크게 편면 친수화 되었다. 그 결과로 볼 때 플라즈마처리에 의해 편면발수 가공으로 서의 효과를 얻을 수 있었다. SEM 관찰을 통해 Polyester직물 및 Nylon/PU혼방 직물에 플라즈마 처리한 후 처리시간에 따른 펴면의 발수가공 층이 파괴되는 것을 알 수 있었다. 이는 표면에서의 발수효과가 플라즈마처리에 의해 친수화가 진행된 결과와 일치한다.