• Macromolecular Research
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• 제12권1호
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• pp.134-140
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• 2004

Semi-crystalline poly(ethylene terephthalate) (PET) film surfaces were modified with argon and oxygen plasmas by radio-frequency (RF) glow discharge at 240 mTorr/40 W; the changes in topography and surface structure were investigated by atomic force microscopy (AFM) in conjunction with specular reflectance of infrared microspectroscopy (IMS). Under our operating conditions, analysis of the AFM images revealed that longer plasma treatment results in significant ablation on the film surface with increasing roughness, regardless of the kind of plasma used. The basic topographies, however, were different depending upon the kind of gas used. The specular reflectance analysis showed that the ablative mechanisms of the argon and oxygen plasma treatments are entirely different with one another. For the Ar-plasma-treated PET surface, no observable difference in the chemical structure was observed before and after plasma treatment. On the other hand, the oxygen-plasma-treated PET surface displays a significant decrease in the number of aliphatic C-H groups. We conclude that a constant removal of material from the PET surface occurs when using the Ar-plasma, whereas preferential etching of aliphatic C-H groups, with respect to, e.g. , carbonyl and ether groups, occurs upon oxygen plasma.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.282-289
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• 2010

In preparation of silica aerogel-based hybrid coating materials, the combination of hydrophobic aerogel with organic polar binder material is shown to be very limited due to dissimilar surface property between two materials. Accordingly, the surface modification of the aerogel would be required to obtain compatibilized hybrid coating sols with homogeneous dispersion. In this study, the surface of silica aerogel particles was modified by using both surfactant adsorption and heat treatment methods. Four types of surfactants with different molecular weights and HLB values were used to examine the effect of chain length and hydrophilicity. The surface property of the modified aerogel was evaluated in terms of visible observation for aerogel dispersion in water, water contact angle measurement, and FT-IR analysis. In surface modification using surfactants, the effects of surfactant type and content, and mixing time as process parameter on the degree of hydrophilicity for the modified aerogel. In addition, the temperature condition in modification process via heat treatment was revealed to be significant factor to prepare aerogel with highly hydrophilic property.

• 대한금속재료학회지
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• 제47권11호
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• pp.748-753
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• 2009

The surface morphology and the surface roughness of n-type SiC induced by wet-treatment using 45% KOH and buffered oxide etchant (BOE-1HF : $6H_2O$) were investigated by atomic force microscopy (AFM). While Si-face of SiC could be etched by alkali solutions such as KOH, acidic solutions such as BOE were hardly able to etch SiC. When the rough SiC samples were used, the surface roughness of etched sample was decreased after wet-treatment regardless of etchant, due to the planarization the of surface by widening of scratches formed by mechanical polishing. It was observed that the initial etching was affected by the energetically unstable sites, such as dangling bond and steps. However, when a relatively smooth sample was used, the surface roughness was rapidly increased after treatment at $180^{\circ}C$ for 1 hr and at room temperature for 4 hr by using KOH solution, resulting from the nano-sized structures such as pores and bumps. This indicates that porous SiC surface can be achieved by using purely chemical treatment.

• 폴리머
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• 제29권6호
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• pp.581-587
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• 2005

상업용 폴리우레탄(PU) 필름의 표면 개질 목적으로 대기압에서 플라스마를 발생시키기 위한 dielectric barrier discharge(DBD) 구조의 평판형 플라스마 반응기 내에서 이온화된 아르곤 플라스마를 사용하였다. 플라스마 처리 공정변수인 처리 시간, 처리 RF-power, 아르곤 가스 유속을 변화시켜가며 접촉각을 측정하여 젖음성과 표면 자유 에너지 변화를 알아보았고, 필름 표면 위에 과산화물을 최대로 도입시키기 위해 플라스마 처리 공정변수를 최적화하였다. 대기압 플라스마 처리 시간 70초, RF-power 120 W, 아르곤 가스유속 6 liter per minute(LPM)에서 가장 높은 젖음성과 표면 자유 에너지 값을 보였고, 1,1-diphenyl-2-picrylhydrazy(DPPH) 법을 사용하여 PU 필름의 표면에 생성된 과산화물의 농도를 정량한 결과, 처리 시간 30초, RF-power 80 W, 아르곤 가스유속 6 LPM의 플라스마 처리 조건에서 최대 2.1 nmol/$\cm^{2}$의 과산화물이 생성되었다.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2883-2888
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• 2013

To enhance the power conversion efficiency of dye-sensitized solar cell (DSSC), the surface of titanium dioxide ($TiO_2$) photoelectrode was modified by hydroxylation treatment with $NH_4OH$ solution at $70^{\circ}C$ for 6 h. The $NH_4OH$ solutions of various concentrations were used to introduce the hydroxyl groups on $TiO_2$ surface. As the concentration of $NH_4OH$ was increased, the short-circuit current density ($J_{SC}$) value and conversion efficiency of solar cells were increased because the amount of adsorbed dye molecules on $TiO_2$ surface was increased. As a result of the surface modification to introduce hydroxyl groups, the concentration of adsorbed dye on the $TiO_2$ surface could be improved up to 32.61% without the changes of morphology, surface area and pore volume of particles. The morphology, the specific surface area, the pore volume and the chemical states of $TiO_2$ surface were characterized by using FE-SEM, $N_2$ adsorption-desorption isotherms and XPS measurements. The amount of adsorbed dye and the performance of fabricated cells were analyzed by using UV-Vis absorption spectroscopy and solar simulator.

• 한국터널지하공간학회 논문집
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• 제14권1호
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• pp.79-91
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• 2012

곡면 FRP 패널 부재는 생산방식 및 생산설비 등의 제한으로 일정한 폭을 갖는 제품으로 생산되며, 이러한 곡면 FRP 부재를 이용하여 제작 공장 또는 현장에서 FRP 부재간 연결을 통한 연속 시공으로 목적대상 구조물을 시공할 수 있다. FRP 부재간 연결방법은 크게 화학적 연결, 기계적 연결, 그리고 복합적인 연결방법 등이 있으며, 이 가운데 접착용 수지를 이용한 화학적 연결이 가장 보편적으로 적용되고 있다. 따라서 FRP 부재의 연결부 최적화설계를 위하여 표면처리 조건 및 접착제 종류 등을 매개변수로 직접전단 시험을 수행하였다. 시험결과 sand paper를 이용한 연마 또는 sand blasting으로 FRP 부재 표면 처리 조건 및 에폭시 또는 아크릴계 접착제가 가장 효과적인 접합방식인 것으로 나타났다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.35-36
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• 2003

The purpose of this work is to investigate the surface modification of LDPE film via corona discharge treatment and subsequent graft polymerization, and their effect on the resulting dyeability is studied in terms of the surface functional groups, surface energetics, and acid-base interaction between the modified LDPE and the dyes used.

• Transactions on Electrical and Electronic Materials
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• 제8권5호
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• pp.211-214
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• 2007

Chemical and morphological changes of phenol formaldehyde-based photoresist after $O_2$ radiofrequency(RF) plasma treatment depending on exposure time and source power were investigated. It was found that etch rate of photoresist sharply increased after discharge turn on and reached a limit with increase in plasma exposure time. Contact angle measurements and X-ray photoelectron spectroscopy(XPS) analysis showed that the surface chemical structure become nearly constant after 15 sec of the treatment. Atomic force microprobe(AFM) measurements were shown that surface roughness was increased with plasma exposure time.

• Membrane and Water Treatment
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• 제7권4호
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• pp.355-365
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• 2016

The improvement of fouling resistance of porous polymeric membrane is one of the most important targets in membrane preparation for water purification in many process like wastewater treatment. Membranes can be modified by various techniques, including the treatment of polymer material, blending of hydrophilic polymer into polymer solution, and post treatment of fabricated membrane. This research proposed the modifications of morphology and surface property of hydrophobic membrane by blending polyethersulfone (PES) with three polymeric additives, polyvinylpyrrolidone (PVP), Pluronic F127 (Plu), and Tetronic 1307 (Tet). PES hollow fiber membranes were fabricated via dry-wet spinning process by using a spinneret with inner and outer diameter of 0.7 and 1.0 mm, respectively. The morphology changes of PES blend membrane by those additives, as well as the change of performance in ultrafiltration module were comparatively observed. The surface structure of membranes was characterized by atomic force microscopy and Fourier transform infra red spectroscopy. The cross section morphology of PES blend hollow fiber membranes was investigated by scanning electron microscopy. The results showed that all polymeric additives blended in this system affected to improve the performances of PES membrane. The ultra-filtration experiment confirmed that PES-PVP membrane showed the best performance among the three membranes on the basis of filtration stability.

• 접착 및 계면
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• 제6권3호
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• pp.1-9
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• 2005

본 연구에서는 대기압 플라스마 공정으로 표면 처리 시 PMMA 시편의 표면 자유 에너지에 영향을 주는 인자인 radio frequency (RF) 플라즈마 전압(W), 처리시간(s), 방전 글로우와 시료와의 간격(mm) 그리고 아르곤 가스의 유량(LPM)에 대해 실험 계획법(Design of Experiment, DOE)을 적용한 최적화 실험을 실시하였다. 실험 결과, PMMA의 표면 자유 에너지 증가에 가장 큰 영향을 미치는 인자는 플라즈마 방전 글로우와 시료와의 간격(mm), 처리시간(t), 플라즈마 전압(W) 순으로 확인되었다. 또한 표면에 상호 영향을 미치는 플라즈마 전압과 처리시간에 대한 복합매개변수 형태의 power dose (J)에 따른 의존성을 확인했을 때 1500 J에서 최대의 표면 에너지 증가를 보임을 확인하였다. XPS, AFM 분석을 통해 플라즈마 처리 후 PMMA 표면에 새로운 관능기의 도입과 표면 거칠기 변화를 관찰하였다. 플라즈마 처리에 의한 PMMA plate의 표면 자유 에너지의 변화는 플라즈마 처리에 의한 관능기의 도입과 표면적의 변화에 영향을 받는 것으로 생각된다.