• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.1038-1042
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• 2008

Mono and multilayer TiO2(Fe, $PEG_{600}$) films were deposited by the dip-coating on $SiO_2$/glass substrate using sol-gel method. In an attempt to improve the antibacterial properties of doped $TiO_2$ films, the influence of the iron oxides and polyethilenglycol ($PEG_{600}$) on the morphological, optical, surface chemical composition and biological properties of nanostructured layers was studied. Complementary measurements were performed including Spectroscopic Ellipsometry (SE), Scanning Electron Microscopy (SEM) coupled with the fractal analysis, X-Ray Photoelectron Spectroscopy (XPS) and antibacterial tests. It was found that different concentrations of Fe and $PEG_{600}$ added to coating solution strongly influence the porosity and morphology at nanometric scale related to fractal behaviour and the elemental and chemical states of the surfaces as well. The thermal treatment under oxidative atmosphere leads to films densification and oxides phase stabilization. The antibacterial activity of coatings against Escherichia Coli bacteria was examined by specific antibacterial tests.

• 한국재료학회지
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• 제24권3호
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• pp.159-165
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• 2014

This study is research on the thermal emissivity depending on the alignment degrees of graphite flakes. Samples were manufactured by a slurry of natural graphite flakes with organic binder and subsequent dip-coating on an aluminum substrate. The alignment degrees were controlled by applying magnetic field strength (0, 1, and 3 kG) to the coated samples. The alignment degree of the sample was measured by XRD. The thermal emissivity was measured by an infrared thermal image camera at $100^{\circ}C$. The alignment degrees were 0.04, 0.11, and 0.17 and the applied magnetic field strengths were 0, 1, and 3 kG, respectively. The thermal emissivities were 0.829, 0.837, and 0.844 and the applying magnetic field strengths were 0, 1, and 3 kG, respectively. In this study the correlation coefficient, $R^2$, between thermal emissivity and alignment degree was 0.997. Therefore, it was concluded that the thermal emissivities are correlated with the alignment degree of the graphite flakes.

• 공업화학
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• 제30권5호
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• pp.633-638
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• 2019

실내공기질 중 지하시설은 휘발성유기화합물(VOC, volatile organic compound)의 처리가 미흡한 실정이며, 이를 환기와 같은 확산법이 아닌 오염물질 저감하기 위하여 다양한 제조, 활성화법을 이용해 메탈 필터에 흡착성을 부여한 제올라이트 코팅 흡착 필터소재를 제조하였다. 그 결과, 메탈폼 지지체 대비 약 2~20배 이상 흡착 성능의 증진을 확인하였으며 이는 기공의 증진에 기반함을 SEM 분석으로 확인하였다. 또한 리그닌을 첨가함에 따라 13.95 mg/g의 흡착 성능을 확보하였으며, 세척 후에도 평균 13.25 mg/g의 유사한 흡착 성능을 확보하여 높은 내구성을 가진 흡착 필터소재를 제조하였음을 확인하였다. 개발된 흡착 필터소재는 지하시설 내 기계적 환기로의 농도 저감이 아닌 근본적으로 VOCs를 제어할 수 있는 해결방법으로 제시할 수 있을 것으로 판단하였다.

• 접착 및 계면
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• 제20권2호
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• pp.66-70
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• 2019

소수성 폴리프로필렌 섬유의 표면을 상압 플라즈마 공정을 이용하여 표면처리하였다. 친수성으로 개질된 섬유를 수용성 폴리비닐프롤리돈 (poly(N-vinylpyrrolidone, PVP) 코팅액에 딥코팅하여 PVP 막을 형성하였다. 섬유 표면에 코팅된 PVP 막은 15 kGy 선량의 전자 빔 조사를 통해 가교되어, 폴리프로필렌 섬유의 표면이 PVP 하이드로젤로 균일하게 코팅된 것을 확인하였다. PVP 하이드로젤 코팅막의 두께는 코팅액의 농도를 조절하여 제어할 수 있었다. 단계적인 표면처리, PVP 코팅, 그리고 하이드로젤 막의 형성에 따른 특성은 접촉각, 전자현미경, 광학현미경 등을 통해 분석되었다.

• 대한금속재료학회지
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• 제46권7호
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• pp.427-436
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• 2008

The effect of dewpoints on annealing behavior and coating characteristics such as wettability and galvannealing kinetics was studied by annealing 0.3wt%Si - 0.1~0.4wt% Mn added interstitial-free high strength steels(IF-HSS). The 0.3wt%Si-0.1wt%Mn steel exhibited good wettability with molten zinc and galvannealing kinetics after annealing when the dewpoint of $H_2-N_2$ mixed gas was above $-20^{\circ}C$. It is shown that the wettability and galvannealing kinetics are directly related to the coverage of the external(surface) oxide formed by selective oxidation during annealing. At $N_2-15%H_2$ annealing atmosphere, the increase of dewpoint results in a gradual transition from external to internal selective oxidation. The decrease of external oxidation of alloying elements with a concurrent increase of their subsurface enrichment in the substrate, showing a larger surface area that was free of oxide particles, contributed to the improved wettability and galvannealing kinetics. On the other hand, the corresponding wettability and galvannealing kinetics were deteriorated with the dewpoints below $-20^{\circ}C$. The continuous oxide layer of network and/or film type was formed on the steel surface, leading to the poor wettability and galvannealing kinetics. It causes a high contact angle between annealed surface and molten zinc and plays an interrupting role in interdiffusion of Zn and Fe during galvannealing process.

• 한국표면공학회지
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• 제53권6호
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• pp.293-299
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• 2020

The characteristics of the polycarbosilane (PCS)-based composite ceramic layer was studied by controlling the curing temperature. The stress at the interface of the graphite and SiOC composite layer was evaluated v ia finite element analysis. As a result, the tensile stress was released as the carbon ratio of the SiC decreases. In experiment, the SiOC layers were coated on the VDR graphite block by dip-coating process. It was revealed that the composition of Si and C was effectively adjusted depending on the curing temperature. As the solution-based process is employed, the surface roughness was reduced for the appropriate PCS curing temperature. Hence, it is expected that the cured SiOC layer can be utilized to reduce cracking and peeling of SiC ceramic composites on graphite mold by improving the interfacial stress and surface roughness.

• Composites Research
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• 제34권4호
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• pp.264-268
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• 2021

이 연구에서 우리는 3차원 계층적 나노구조화된 유/무기 복합 표면을 가진 소수성 코팅/필름을 제조하는 방법을 제안한다. 먼저 근접장 나노패터닝(PnP)이라 불리는 첨단 포토리소그래피 기술을 통해 에폭시 기반의 대면적 3차원 정렬 나노다공성 템플릿을 준비하였다. 이후, 딥 코팅을 통해 평균 직경이 22 nm인 실리카 나노입자를 템플릿에 조밀하게 함침시켜 계층적 구조화된 표면을 구현하였다. 표면에 공존하는 마이크로 및 나노 스케일 거칠기로 인해, 제조된 복합 필름은 대조군에 비해 물에 대한 높은 접촉각(>137도)을 나타내었다. 따라서 본 연구를 통해 개발된 소재 및 공정은 전통적인 코팅/필름 분야에서 다양하게 활용될 수 있을 것으로 기대된다.

• 한국식생활문화학회지
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• 제22권4호
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• pp.434-440
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• 2007

Yackwa is used as one of foods prepared for traditional rituals and holidays and enjoyed as snacks. Since Yackwas are fried, they contain oil, which can cause rancidity and undermines the freshness of Yackwas during distribution to retailers, not to mention a high level of calories. The study aims to develop baked Yackwas and analyze the quality in terms of calorie levels and characteristics by baking Yackwas in oven. Calorie level was 4.65 kcal/g in fried Yackwa, 3.96 kcal/g in baked Yackwa, and 2.95 kcal/g in baked peanut Yackwa prior to dip coating of grain syrup. baked Yackwa showed hardness of 13476.33 $g/cm^2$ before dipping in grain syrup, which was harder than 1912.56 $g/cm^2$ of fried Yackwa. After grain syrup coating, hardness of baked Yackwa reduced more significantly, compared with that of fried Yackwa, as grain syrup permeated through texture of Yackwa. And less hardness makes baked Yackwa tastier. Sensory evaluation was measured in a 5-point scale. Scores for texture and taste of baked Yackwa outpaced those of fried Yackwa. Score for the overall quality was 3.65 in baked Yackwa and 3.25 in baked peanut Yackwa, compared to 2.85 of fried Yackwa, indicating a higher potential of commercializing(p<0.05).

• 전기학회논문지
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• 제57권6호
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• pp.1012-1016
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• 2008

[ $TiO_2-V_2O_5$ ] sol was fabricated using sol-gel method and $TiO_2-V_2O_5$ thin films were fabricated using dip-coating method. $V_2O_5$ sol was added 0.01mole, 0.03mole, 0.05mole into $TiO_2$ sol. As a results of crystalline properties, $V_2O_5$ peaks were not found in spite of $V_2O_5$ additive. Thickness of thin films increased $0.1{\sim}0.25{\mu}m$ every a dipping. Capacitance of thin films increased with increasing heat treatment temperature and it increased largest at $700^{\circ}C$. Capacitance of thin films decreased with increasing $V_2O_5$ additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3991-3995
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• 2011

$TiO_2-SiO_2-In_2O_3$ nanocomposite thin film was deposited on the glass substrates using a dip coating technique. The morphology, surface composition, surface hydroxyl groups, photocatalytic activity and hydrophilic properties of the thin film were investigated by AFM, XPS, methyl orange decoloring rate and water contact angle measurements. The hydroxyl content for $TiO_2$, $TiO_2-SiO_2$ and $TiO_2-SiO_2-In_2O_3$ nanocomposite films was calculated to be 11.6, 17.1 and 20.7%, respectively. $TiO_2-SiO_2-In_2O_3$ film turned superhydrophilic after 180-min irradiation with respect to pure $TiO_2$ and $TiO_2-SiO_2$ thin films. The photocatalytic decomposition of methyl orange for $TiO_2$, $TiO_2-SiO_2$ and $TiO_2-SiO_2-In_2O_3$ thin films was measured as 38.19, 58.71 and 68.02%, respectively. The results indicated that $SiO_2$ and $In_2O_3$ had a significant effect on the hydrophilic, photocatalytic and self-cleaning properties of $TiO_2$ thin film.