• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.7
• /
• pp.483-489
• /
• 2017

The purpose of this study was to propose useful suggestions for enhancing reliability to determine the resistance against surface wetting, KS K 0590, by an imaging process. We validated the standard spray test rating chart for determining quantification standard using JAVA script-based imaging process program. All of the acquired images were processed with the image software, Image J (NIH, Nethesda, MD, USA). The study results are as follows. We established the surface area measurement-based quantitative criteria for determining resistance to surface wetting. The standard spray test rating chart was converted into a numerical standard which leads easy-to-determine ratings. We also validated the procedure for imaging treatment by analyzing quantitative data. We introduced the fluorescence image for determining ratings by enabling threshold settings and binary image conversion as an optimal imaging process. It is expected that imaging-based determination for resistant to surface wetting will serve as an accurate and reliable method for KS K 0590.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.10a
• /
• pp.49-58
• /
• 1998

An experimental study was performed to discover the effect of adsorbed moisture on the rolling resistance behavior of pure silver coated 52100 bearing steel. Plasma surface modifications were performed on the silver coated specimen to change the wetting characteristics. Experiments using a thrust ball beating-typed roiling test-rig were performed under vacuum, dry air and various tmmidity conditions. Results showed that the changes in the wetting characteristics influenced remarkably on the silver particle agglomeration and resulted in the different behavior of rolling resistance with humidity.

• Tribology and Lubricants
• /
• v.15 no.4
• /
• pp.321-327
• /
• 1999

An experimental study was performed to discover the effect of adsorbed moisture on the rolling resistance behavior of pure silver-coated 52100 bearing steel. Plasma surface modifications were performed on the silver-coated specimen to change the wetting characteristics. Experiments using a thrust ball bearing-type rolling test-rig were performed under vacuum, dry air and various humidity conditions. Results showed that the changes in the wetting characteristics influenced remarkably on the silver particle agglomeration and resulted in the different behavior of rolling resistance with humidity.

• Journal of the Korean institute of surface engineering
• /
• v.56 no.1
• /
• pp.1-11
• /
• 2023

Lubricant-impregnated nanoporous surfaces (LIS), which is created by impregnating water-immiscible oil into nanoporous surface structure, have been explored considering wide range of application fields. Due to the lubricant impregnated in nanoporous structure, the surface shows extreme de-wetting with a high mobility of water droplets, so that various functionalities can be realized. The lubricant layer inhibits the contact of corrosive media to porous structure as well as metal substrate, thus the surface improves the corrosion resistance. The water on the surface freeze without any contact to solid porous structure, showing a low ice adhesion for de-icing an anti-icing. The extremely high mobility of water droplets on lubricant-impregnated porous surfaces also contributes the enhancement of condensation heat transfer as well as water harvesting from fog and moisture. Moreover, the bacteria adhesion on metal surface forming biofilms causing serious hygiene issues can be inhibited on the lubricantimpregnated surfaces. Despite of such superior functionalities, the lubricant-impregnated porous surface has a limitation of lubricant depletion by external flow of fluids. Therefore, extensive efforts to improve the durability of lubricant-impregnated surface are required for practical applications.

• The KSFM Journal of Fluid Machinery
• /
• v.13 no.2
• /
• pp.5-11
• /
• 2010

The nanofluidics is characterized by a large surface-to-volume ratio, so that the surface properties strongly affect the flow resistance. We present here the results showing that the effect of wetting properties and the surface roughness may considerably reduce the friction of fluid past the boundaries. For a simple fluid flowing over hydrophilic and hydrophobic surfaces, the influences of surface roughness are investigated by the nonequilibrium molecular dynamics (NEMD) simulations. The fluid slip at near a solid surface highly depends on the wall-fluid interaction. For hydrophobic surfaces, apparent fluid slips are observed on smooth and rough surfaces. The solid wall is modeled as a rough atomic sinusoidal wall. The effects on the boundary condition of the roughness characteristics are given by the period and amplitude of the sinusoidal wall. It was found that the slip velocity for wetting conditions at interface decreases with increasing effects of surface roughness. The results show the surface rougheness and wettability determines the slip or no-slip boundary conditions. The surface roughness geometry shows significant effects on the boundary conditions at the interface.

• Journal of the Korean institute of surface engineering
• /
• v.43 no.3
• /
• pp.142-147
• /
• 2010

We evaluated characteristics of ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) surface treatment for mobile equipment that requires high reliability, in addition to investigating surface treatment processes for semiconductor boards that require high reliability such as regular PCB-package systems, board-on-chip, chip-scaled package (CSP), etc and application for semiconductor package board of SIP, BOC. As a result, it appeared that ENEPIG has superior properties compared to ENIG surface treatment in corrosion resistance, solder junction, wetting, etc. We anticipate that these results will be able to lend credibility to ENEPIG as a low-cost alternative for producing mobile devices such as the cell phones, especially when applied to mass production.

• Polymer(Korea)
• /
• v.32 no.4
• /
• pp.313-321
• /
• 2008

Acrylic pressure sensitive adhesive(PSA) was prepared by UV radiation curing and the peel energy and physical properties of PSA were investigated. The increase of amount of acrylic acid leads to improve the peel energy, associated with the substrate having smooth surface and high layer thickness. The high peel energy is obtained when the direction of irregularity in substrate is horizontal with the peeling direction. This is attributed to the increase of resistance to peeling in spite of decrease of wetting and the result corresponds to our supposition.

• Fibers and Polymers
• /
• v.3 no.4
• /
• pp.174-178
• /
• 2002

A plasma treatment using saturated $CF_4$ gas was employed to improve the resistance of polypropylene fabrics to water wetting. The fabrics were significantly fluorinated even within a short treatment time of 30 seconds. The result of contact angle measurement indicated that such highly hydrophobic surface was considerably durable even after 150 days of aging.

• Journal of Sensor Science and Technology
• /
• v.25 no.3
• /
• pp.213-217
• /
• 2016

The superhydrophobic and superoleophobic meshes surfaces have been used in various applications such as self-cleaning, anti-icing, gas exchange, oil-water separation, sound-wave penetrable anti-wetting structures, etc. In particular, there are many studies for oil-water separation with environmental issues. Because of high pressure and dynamic environment, oil-water separation filters must have stable surface properties as super-hydrophobicity and superoleophobicity. The oleophobicity of surface depends on the surface chemistry and roughness of the surface. The roughness of oleophobic surface enhances its static contact angle and stability. The multi-scale hierarchical structure provides a stable superhydrophobic state by maintaining a Cassie state. In this research, we fabricated a superoleophobic mesh with a multi-scale hierarchical structure to increase the pressure resistance and adjusted a size of the mesh hole.

• Corrosion Science and Technology
• /
• v.22 no.3
• /
• pp.193-200
• /
• 2023

Titanium alloy (grade-4) is commonly used in industrial and medical applications. To improve its corrosion resistance and biocompatibility for medical use, it is necessary to form a titanium oxide film. In this study, the morphology of the oxide film formed by anodizing Ti-grade 4 using different electrolytes was analyzed. Wetting properties before and after surface modification with SAM coating were also observed. Electrolytes used were categorized as A, B, and C. Electrolyte A consisted of 0.3 M oxalic acid and ethylene glycol. Electrolyte B consisted of 0.1 M NH₄F and 0.1 M H₂O in ethylene glycol. Electrolyte C consisted of 0.07 M NH₄F and 1 M H₂O in ethylene glycol. Samples B and C exhibited a porous structure, while sample A formed a thickest oxide film with a droplet-like structure. AFM analysis and contact angle measurements showed that sample A with the highest roughness exhibited the best hydrophilicity. After surface modification with SAM coating, it displayed superior hydrophobicity. Despite having the thickest oxide film, sample A showed the lowest insulation resistance due to its irregular structure. On the other hand, sample C with a thick and regular porous oxide film demonstrated the highest insulation resistance.