• Polymer(Korea)
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• v.36 no.4
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• pp.461-469
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• 2012

The surface modification and characterization of Ar-plasma treated polypropylene (PP) blend are investigated using x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement. An increase in Ar-plasma treatment time leads to an increase in wettability, oxygen containing polar functional groups, the amount of talc, and surface roughness on the PP blend surface. A careful observation using SEM indicates that there exists a skin layer consisting of only PP component. The difference in viscosity between PP and rubber particles facilities the formation of skin layer. However, it is found that an increase in Ar-plasma treatment time helps to decrease the thickness of skin layer. Additional methodologies for the elimination of skin layer during injection molding are also discussed. The surface modification and morphological alteration induced by Ar-plasma treatment provides a hydrophilic state, followed by the improvement in wettability, on the PP blend surface.

• Polymer(Korea)
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• v.24 no.6
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• pp.877-885
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• 2000

PLA, PGA and PLGA films were treated with chloric acid mixture solution [70% perchloric acid (HClO$_4$)/potassium chlorate (KClO$_3$) aq. saturated solution, 3 : 2] to increase surface wettability and thus cell compatibility. The surface-treated PLA, PGA, and PLGA films were characterized by the measurement of water contact angle, electron spectroscopy for chemical analysis, and scanning electron microscopy. Surface wettability of chloric acid-treated PLA, PGA, and PLGA film surfaces was gradually increased with increase of treatment time. Unlike EtOH pre-treatment, chloric acid-treated polymer films maintain hydrophilic surface after drying. In cell adhesion test, fibroblasts were cultured on the chloric acid-treated film surfaces for 1 and 2 days. As the surface wettability increased, the cell adhesion on the surface were increased. In conclusion, this study demonstrated that the surface wettability of polymer plays an important role for cell adhesion and proliferation behavior.

• Korean Journal of Materials Research
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• v.11 no.5
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• pp.398-404
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• 2001

Effects of coating treatment of metallic Cu film on SiC for Al/SiC composite were studied. The Copper was deposited on SiC by electroless plating method. Al/sic composite was fabricated at temperature range of $670^{\circ}C$ to 90$0^{\circ}C$ under vacuum atmosphere. The wetting behavior of Al/SiC composite were analysed by SEM and XRD. The coating treatment on SiC improved wettability of Al melt on SiC considerably comparing to the non coated SiC. This improved wettability seems strongly concerned to the increase of chemical reactivity between coated layer and Al matrix. The improvement of wettability of Al melt on the Cu coated SiC was closely related to in the initial stage of reaction. The metallic film played an important role in reducing the interfacial free energy and breaking down the aluminum oxide film through the reaction with Al melt. The wetting behavior of the as-received SiC with Al melt was not uniform, indicated by the contact angles from less than $97^{\circ}$to more than $97^{\circ}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.143.1-143.1
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• 2013

최근 실 기반 microfluidics device는 많은 응용 가능성을 보이고 있다. 예를 들면 의료진단, 환경측정 그리고 식품 안정성 분석 등의 분야에서 사용이 가능하다. 이러한 가능성을 가진 반면 해결해야 하는 문제점들이 존재한다. 실 한가닥에 Capillary force에 의해 빨려 올라오는 액체의 속도를 조절하기 힘들다는 것이다. 속도 조절은 실 기반 microfluidics에서는 매우 중요한 역할을 하는 것이므로 이는 굉장히 치명적일 수 있다. 본 그룹은 울의 젖음성을 변화시킴으로써 그 속도를 조절하였다. 울은 본래 소수성의 성질을 가졌으며 본 그룹의 표면처리를 통하면 친수성을로 바뀌는 것을 확인하였다. 표면처리의 종류와 정도에 따라 친수성을 띄는 정도가 달라지는 것을 확인하였다. 결과적으로는 표면처리에 따라 서로 액체를 빨아들이는 속도가 다른 울들을 microfluidics device에 응용할 수 있다는 결론을 지을 수 있다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.165-166
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• 2012

표면의 젖음성은 어플리케이션의 매우 중요한 점으로, 이것은 표면에너지와 표면의 조도에 의해 결정된다. 표면의 젖음성을 낮추기 위하여 저온 PECVD 공정을 통해 초소수성 박막을 만들었다. $SiO_xC_yH_z$ 필름을 만들기 위하여 RF power을 사용하였고, HMDS (hexamethyl-disilazane) precursor과 함께 수소 기체를 통해 증착하였다. 이 실험에서는 수소와 RF power를 변수로 진행하였고, 이것은 소수성 박막의 표면에너지를 변화시켰다. 필름을 합성한 후 contact angle measurement 및 AFM을 사용해 표면에너지와 표면조도를 관찰하였다. 또한 필름의 화학적 결합을 알기 위해 FT-IR을 이용하였다. 여기에서 표면의 에너지는 표면의 조도와 화학적 결합상태에 의해서 영향을 받았음을 알 수 있었다.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.12-20
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• 2009

Statement of problem: When an implant is fixed, a fixture comes into contact with a tissue fluid. Adhesion of a tissue fluid to a surface of implant is various case by case. Purpose: The ultimate goal of this work is to analyze a correlation between a surface roughness and wettability of implant specimens. A measurement for wettability is performed considering 4 types of specimen implant with surface treatments different from each other to investigate the change of wettability with the elapse of time. Material and methods: Firstly, 20 specimens of titanium were prepared. The specimen were made of a commercial Titanium Grade IV with the diameter of 10 mm and the thickness of 1 mm. According to the method of surface treatment, the specimens were classified into 4 groups of 5 specimens per group. Group A: Machined Surface Group B: Anodized surface Group C: RBM (HA blasting) surface Group D: CMP (calcium methaphosphate) coating surface. Surface roughness of specimen was measured using SV-3000S4 (Mituyoto, Japan). The measurement was based on the standard of JIS1994. Sessile drop method was used to measure the wettability, which measures contact angle between implant disc and saline with the time interval of 5, 10, and 15 seconds. SPSS 11.0 was used to analyze the collected data. In order to analyze the difference of wettability and surface roughness according to implant surface treatment method. The statistical significance was tested with the confidence level of 95%. Pearson's correlation coefficient was used to evaluate the correlation of surface roughness and wettability. Results: The difference of surface roughness was statistically significant in the order of Group C ($1.69{\pm}0.26$), Group D ($1.58{\pm}0.16$), Group B ($0.78{\pm}0.14$) Group A ($0.18{\pm}0.05$). The wettability has also a statistically significant difference, which was in the order of group B ($17.70{\pm}2.66$), Group C ($27.86{\pm}4.52$), Group D ($66.28{\pm}3.70$) Group A ($70.52{\pm}8.00$). There was no difference in wettability with the passage of time. Conclusions: 1. The surface roughness was high in the order of RBM, CMP, Anodized, Machined group (P<.05). 2. The wettability was high in the order of Anodized, RBM, CMP, Machined group (P<.05). 3. There was no statistical significance in the correlation of surface roughness and wettability.

• Composites Research
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• v.28 no.5
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• pp.254-259
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• 2015

Carbon fiber/aluminum (CF/Al) composites were successfully fabricated without pressure casting using wettability modification of carbon fiber. The wettability of liquid aluminum on carbon fibers was enhanced through electroless plating of copper on carbon fibers. Liquid aluminum was well infiltrated into carbon fiber bundles with Cu coating layer due to low wetting angle, and a lot of pores that existed in CF/Al composite without Cu coating on CF were greatly removed. However, a few tiny pores existed in carbon fiber bundles, which is due to not bad wettability between CF and Al but shrinkage cavity that was generated during cooling of CF/Al composite. The tiny pores could be effectively removed by a subsequent rolling.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.677-681
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• 2018

In this study, the carbon block was prepared using the fluorinated coke and binder pitch by molding compression to increase its density. After fluorination, it is confirmed that the fluorine element on the coke surface was introduced up to 24.14 at% using XPS analysis. The wettability between the fluorinated coke and binder pitch was evaluated according to the reaction temperature. From the result of contact-angle tests, it can be found that the wettability was improved up to 64.7% as more fluorine atoms were introduced on the surface of cokes. Also, the density of the carbon block with the highest amount of fluorine increased with 6.8% compared to that of using the carbon block prepared by the untreated cokes.

• Composites Research
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• v.22 no.5
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• pp.8-14
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• 2009

Interfacial evaluation of glass fiber reinforced carbon nanotube (CNT)-epoxy nanocomposite was investigated by micromechanical technique in combination with wettability test. The contact resistance of the CNT-epoxy nanocomposite was measured using a gradient specimen, containing electrical contacts with gradually-increasing spacing. The contact resistance of CNT-epoxy nanocomposites was evaluated by using the two-point method rather than the four-point method. Due to the presence of hydrophobic domains on the heterogeneous surface, the static contact angle of CNT-epoxy nanocomposite was about $120^{\circ}$, which was rather lower than that for super-hydrophobicity. For surface treated-glass fibers, the tensile strength decreased dramatically, whereas the tensile modulus exhibited little change despite the presence of flaws on the etched fiber surface. The interfacial shear strength (IFSS) between the etched glass fiber and the CNT-epoxy nanocomposites increased due to the enhanced surface energy and roughness. As the thermodynamic work of adhesion, $W_a$ increased, both the mechanical IFSS and the apparent modulus increased, which indicated the consistency with each other.

• Journal of Adhesion and Interface
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• v.18 no.4
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• pp.171-178
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• 2017

Recently, layer-by-layer (LbL) assembly has emerged as a promising fabrication technique in controlling surface wetting properties. LbL assembly technique is eco-friendly versatile technique to control the hierarchical structure and surface properties in nano- and micro-scale by employing a variety of materials (e.g., polymers, surfactants, nanoparticles, etc.). This article reviews recent progress in controlling the surface wetting using LbL technique. In particular, technical trends and research findings on fabrication and the applications of superhydrophobic, superhydrophilc, and superoleophobic/superhydrophilic LbL surfaces are extensively explained. Additionally, basic principles and fabrication methods in emerging areas such as omniphobic, self-healing, intelligent and responsive LbL surfaces are discussed.