• Journal of Surface Science and Engineering
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• v.48 no.4
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• pp.163-168
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• 2015

Graphene has attracted much attention due to its remarkable physical properties and potential applications in many fields. In special, the electronic properties of graphene are influenced by the number of layer, stacking sequence, edge state, and doping of foreign elements. Recently, many efforts have been dedicated to alter the electronic properties by doping of various species, such as hydrogen, oxygen, nitrogen, ammonia and etc. Here, we report our recent results of plasma doping on graphene. We prepared mechanically exfoliated graphene, and performed the plasma treatment using ammonia gas for nitrogen doping. The direct-current plasma system was used for plasma ignition. The doping level was estimated from the number of peak shift of G-band in Raman spectra. The upshift of G-band was observed after ammonia plasma treatment, which implies electron doping to graphene.

• Fibers and Polymers
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• v.6 no.2
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• pp.113-120
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• 2005

Helium-oxygen plasma treatments were conducted to modify poly(trimethylene terephthalate) (PIT) and poly(ethylene terephthalate) (PET) warp knitted fabrics under atmospheric pressure. Lubricant and contamination removals by plasma etching effect were examined by weight loss $(\%)$ measurements and scanning electron microscopy (SEM) analysis. Surface oxidation by plasma treatments was revealed by x-ray photoelectron spectroscopy (XPS) analyses, resulting in formation of hydrophilic groups and moisture regain $(\%)$ enhancement. Low-stress mechanical properties (evaluated by Kawabata evaluation system) and bulk properties (air permeability and bust strength) were enhanced by plasma treatment. Increasing interfiber and interyarn frictions might play important roles in enhancing surface property changes by plasma etching effect, and then changing low-stress mechanical properties and bulk properties for both fabrics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.340-346
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• 1998

In this study, we intended to investigate aging effect of polyimide prepared by VDPD(vapor deposition polymerized method). The prepared polymide was treated by the oxygen and argon gas plasma. And we evaluated the polyimide treated by plasma from contact angle, surface leakage current, FT-IR and SEM. We know that the structure of polyimide at surface are changed to amide structure by plasma treating. It seems that strong energy of plasma causes breaking the molecular chin of the polyimide. And surface roughness increases with plasma treating time increased and sequentially the wettability and leakage current increases.

• Journal of Surface Science and Engineering
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• v.37 no.2
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• pp.119-127
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• 2004

In order to develop the corrosion and wear resistance of stainless steels, effects of plasma-nitriding on the surface characteristics of stainless steels containing Nb were investigated by utilizing a potentiostat. It was found that plasma nitriding at $350^{\circ}C$, compared with $500^{\circ}C$, produced a good corrosion resistance as nitriding time increased, whereas stainless steel containing low Nb content showed that pitting potential and corrosion potential decreased.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.312-312
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.146-146
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• 2004

• Proceedings of the Korean Vacuum Society Conference
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• 2005.08a
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• pp.63-63
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.96-96
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• 2010

To improve surface wettability, each sample was treated by atmospheric pressure plasma (APP) using dielectric barrier discharge (DBD) system. Argon and oxygen gases were used for treatment gas to modify the $TiO_2$ surface by APP with RF power range from 50 to 200 W. Water contact angle was decreased from $20^{\circ}$ to $10^{\circ}$ with argon only. However, water contact angle was decreased from $20^{\circ}$ to < $1^{\circ}$ with mixture of argon and oxygen. Water contact angle with $O_2$ plasma was lower than water contact angle with Ar plasma at the same RF power. It seems to be increasing the polar force of $TiO_2$ surface. Also, analysis result of X-ray photoelectron spectra (XPS) shows the increase of intensity of O1s shoulder peak, resulting in increasing of surface wettability by APP. Moreover, each water contact angle increased according to increase past time. However, contact angle increase with plasma treatment was lower than without plasma treatment. Additionally, the efficiency of $TiO_2$ photocatalyst was improved by plasma surface-treatment through the degradation experiment of phenol

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.94-100
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• 2005

The plasma, ionized gas state, is generally composed as the 4th state in the universe. Generating the plasma artificially has been studied by spending energy and it has been applied so much in human's life. There are several merits to modify the surface of polymer using plasma. Above all, plasma maintains the properties of polymer itself, but changes the properly of polymer surface only. Also, it is the environmentally fraternized because there are no waste processing from organic solvent. Furthermore, it is possible that continuous automated-processing in case of high-pressure plasma. Therefore, we have tried the reforming of surface to rise the adhesive strength between the material of polymer, and have experimented rising the adhesive strength through peel strength by virtue of processing time and using gas, of course, confirmed the change of polymer surface through measuring the contact angle analysis and scanning electron microscopy(SEM).

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.96-102
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• 2010

It is still controversial where the improved stability of n-octadecyltriethoxysilane self-assembled monolayer (OTE SAM) on plasma-pretreated mica surface exactly originates from. To date, it has been well known that the extensive cross-polymerization between silane headgroups is a crucial factor for the outstanding mechanical strength of the monolayer. However, this study directly observed that the stability comes not only from the cross-links but also, far more importantly, from the direct chemical bonds between silane headgroups and mica surface. To observe this phenomenon, n-octadecyltrichlorosilane monolayers were self-assembled on both untreated and plasma treated mica surfaces, and their adhesion properties at various stress conditions and force profiles in pure water were investigated and compared through the use of the surface forces apparatus technique. It revealed that, in pure water, there is a substantial difference of stability between untreated and plasma treated cases and the plasma treated surface is mechanically much more stable. In particular, the protrusion behavior of the monolayer during contact repetition experiment was always observed in the untreated case, but never in the plasma treated case. It directly demonstrates that the extensive chemical bonds indeed exist between silane head-groups and plasma treated mica surface and dramatically improve the mechanical stability of the OTE monolayer-coated mica substrate.