• Transactions on Electrical and Electronic Materials
• /
• v.11 no.6
• /
• pp.266-270
• /
• 2010

The effect of an Ar plasma treatment on polycarbonate substrates was investigated using $TiO_2$ coatings produced by reactive ion-beam assisted sputtering. The typical pressure used during sputtering was about $10^{-4}$ Torr. After the Ar plasma treatment, the contact angle of a water droplet was reduced from $88^{\circ}$ to $52^{\circ}$ and then further decreased to $12^{\circ}$ with the addition of oxygen into the chamber. The surface of the polycarbonate substrate hanged from hydrophobic to hydrophilic with these treatments and revealed its changing nano-scale roughness. The $TiO_2$ films on the treated surface showed various colors and periodic ordering dependant on the film thickness due to optical interference.

• Textile Coloration and Finishing
• /
• v.34 no.3
• /
• pp.165-172
• /
• 2022

Polypropylene(PP) is a textile material with various functions such as eco-friendliness, lightness, and elasticity. Although most synthetic fibers can be dyed and finished, but original PP is difficult to dye or finish due to its extremely hydrophobic properties, so its application expansion is limited. In order to solve this problem, dyeable PP was developed, and various researches on textiles for clothing such as mass production technology, fine fiberization and performance improvement are in progress. Plasma treatment is a processing method for modifying the surface of fabrics, and has effects such as hydrophilization, deepening color, improving adhesion, and surface polymerization. In this study, plasma treatment was applied to study changes in hydrophilization properties of dyeable PP, surface changes before and after plasma treatment and performance according to hydrophilization.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.3
• /
• pp.207-212
• /
• 2010

Purpose: Rigid gas permeable (RGP) contact lenses, based on fluorosilicone acrylate, were treated with plasma in air. Methods: The chemical compositions were analyzed by using X-ray photoelectron spectroscopy (XPS), the surface morphology and roughness of RGP contact lenses were observed by using atomic force microscopy (AFM), and the wettability changes were estimated by wetting angle measurement. Results: As the contact lenses were treated by the plasma, the F contents decreased significantly, and the O and Si contents increased on the surface. The number of oxygen-containing hydrophilic radicals (C-O and Si-O) increased greatly, the hydrophobic surface decreased, and the wetting angle increased. But the C-O bonds created with exchange of the fluorine did not increase a wettability. The surface compositions were not remarkably changed for the 6 months after plasma treatment, but the wetting angle increased again. Conclusions: It was considered that the improved wettability of the RGP contact lenses of high fluorine content after plasma treatment was affected by the activation of surface, the increase of Si-O, and the decrease of hydrophobic surface.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.9
• /
• pp.1323-1329
• /
• 2015

The WO₃/Ag/WO₃ transparent thin films are fabricated by the RF magnetron sputtering. This has a transmittance of front and rear about 90% in the visible light range and surface resistance of 6.41Ω/□. In this paper, we analyzed the surface characteristics caused by the working pressure and O₂ plasma surface treatment to apply a transparent electrode that was prepared to the laminated structure with other materials. The working pressure was changed in the WO₃ film to 10mTorr, 7mTorr, and 5mTorr, it showed a lower than roughness of conventional ITO. In addition, by 55.5774 J/m² at 5mTorr, it shows the hydrophobic property with lower process pressure. O₂ plasma surface treatment was changed at the condisions of the RF power to 150W, 100W, and 50W and the process time to 240s, 180s, 120s, and 60s. The surface roughness are the maximum roughness(Rmax) 6.437nm and the average roughness(Rq) 0.827nm at RF power 150W, and the maximum roughness (Rmax) 6.880nm and the average roughness (Rq) 0.839nm at process time 240sec. It showed a lower value than the surface treatment. also about working pressure and process time is increased, it showed the hydrophobic.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.2 s.39
• /
• pp.27-31
• /
• 2006

We reported the grain growth of pentacone on $HfO_2$ film depending on OTS treatment. The hydrophilic $HfO_2$ thin film was changed into hydrophobic with less interface energy by OTS treatment. The grain size of pentacene on OTS/$HfO_2$ film was increased from 50 nm to 90 nm with the variation of surface energy and the structure was maintained 3-dimensional island structure. Pentacene on OTS/$HfO_2$ surface was directionally arrayed due to appearance of the only thin film phase without bulk phase by OTS treatment.

• Journal of Korean Society on Water Environment
• /
• v.39 no.6
• /
• pp.465-474
• /
• 2023

The chemical composition and molecular weight characteristics of dissolved organic matter (DOM) exert a profound influence on the efficiency of organic matter removal in water treatment systems, acting as efficiency predictive indicators. This research evaluated the primary chemical and molecular weight properties of DOM derived from diverse sources, including rivers, lakes, and biomasses, and assessed their relationship with the efficiency of coagulation/flocculation treatments. Dissolved organic carbon (DOC) removal efficiency through coagulation/flocculation exhibited significant correlations with DOM's hydrophobic distribution, the ratio of humic-like to protein-like fluorescence, and the molecular weight associated with humic substances (HS). These findings suggest that the DOC removal rate in coagulation/flocculation processes is enhanced by a higher presence of HS in DOM, an increased influence of externally sourced DOM, and more presence of high molecular weight compounds. The results of this study further posit that the efficacy of water treatment processes can be more accurately predicted when considering multiple DOM characteristics rather than relying on a singular trait. Based on major results from this study, a predictive model for DOC removal efficiency by coagulation/flocculation was formulated as: 24.3 - 7.83 × (fluorescence index) + 0.089 × (hydrophilic distribution) + 0.102 × (HS molecular weight). This proposed model, coupled with supplementary monitoring of influent organic matter, has the potential to enhance the design and predictive accuracy for coagulation/flocculation treatments targeting DOC removal in future applications.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.1
• /
• pp.116-124
• /
• 2017

A plate-type inorganic pigment complex was manufactured in a manner that treats the surface of the complex by adjusting zeta potential between talc, an inorganic pigment used as a material for color cosmetics, and hydrophobic silica. Talc, which is usually used in the prescription of color cosmetics, is a plate-type, white-colored inorganic substance with good application and spreadability to skin. Furthermore, it features excellent dispersibility and extensibility as well as outstanding heat tolerance, light stability, and chemical resistance. In general, silica contributes to durable makeup and stabilized formulation. This paper covers a process of manufacturing an inorganic pigment complex, where hydrophobic silica was applied to the surface of talc by using differences in zeta potential after the surface charges of talc and hydrophobic silica had been adjusted with cationic and anionic surfactants, respectively. The resulting inorganic pigment complex was composed of talc whose surface is coated hydrophobic silica to the thickness of $1{\mu}m$ or less, which developed an effective hydrophobic property. Zeta potential was measured to analyze the surface charge of an inorganic pigment, and FT-IR, used to check the functional group of a surfactant, was applied to treat the surface of the pigment. The surface of the inorganic pigment complex was observed employing SEM, EDS, and FIB, while its structure was confirmed with XRD and FT-IR.

• KSBB Journal
• /
• v.15 no.4
• /
• pp.366-369
• /
• 2000

The soluble paclitaxel was found in the supernatant of the plant cell cultures of Taxus chinensis, The percentage of soluble paclitaxel depends on paclitaxel concentration in bioreactor. As paclitaxel concentration decreases the percentage of soulbe paclitaxel increases. it is therefore important to develop a new process for the recovery of soluble paclitaxel. The use of hydrophobic resin HP20 gives nearly perfect recovery of paclitaxel in supernatant. The resin was more effective in treatment of th cell and debris free filtrate probably because of the reduced solids content In this case 3 g.l resin and 1 day reaction were enough for recovery the soluble paclitaxel in medium.

• Journal of Korea Soil Environment Society
• /
• v.4 no.3
• /
• pp.95-104
• /
• 1999

Comparative biodegradation studies of liquid and solid alkanes and of two different solid alkanes were conducted by an isolated Acinetobacter sp., which degraded crude oil alkanes simultaneously. for the determination of degradation mechanism of hydrophobic crude oil constituents. Also a model oil experimental system composed of a solid alkane. heneicosane, as a substrate and a non-degradable non-aqueous phase liquid. pristane, as an oil matrix was established and studied. It was proposed that the Acinefobacter sp. utilized hydrophobic substrates directly on the surface of them with no difference in the degradation rates between the liquid and solid alkanes. On the basis of the results from the heneicosane/pristane system which imitates crude oil matrix containing solid constituents. the crude oil matrix was considered to reduce the bioavailability of contained substrates by reducing the specific surface area of substrates to contact with microorganisms.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.1
• /
• pp.64-73
• /
• 2010

This study was conducted to modify the surface properties of papers by formation of hydrophobic self-assembled monolayer(SAM) on paper surface with silanes. A base paper I(0.5% AKD) and base paper II(1.0-1.5% AKD) were reacted with silanes(PFDTES, DMDCS, MODDCS) by immersion method and vapor deposition method. Hydrophobic SAMs(contact angle value>$120^{\circ}C$) were obtained on all papers after treatment with $10^{\mu}l$ PFDTES for 15min, with $50^{\mu}l$ DMDCS for 30min, with $50^{\mu}l$ MODDCS for 300min. When applying PFDTES to paper surface, lower silane concentration and shorter reaction time were required, whereas MODDCS with long alkyl chain required the longest reaction time of 300min. The st$\ddot{o}$ckight sizing degree of silane treated papers were increased between 105sec(base paper I) and 130sec(base paper II). The wet tensile strength of PFDTES-treated base papers(I, II) increased by 10-34% after SAM formation. However, the wet tensile strength of the DMDCS-treated base paper(I) was found to decrease from 0.067kN/m to 0.038kN/m; this may due to the cellulose degrading as a result of generated hydrogen chloride when hydroxyl group of cellulose were reacted with DMDCS. No apparent changes of PPS roughness on silane-treated papers are observed. The ATR-IR spectrum showed absorption peak located at 465 and 1200cm-1 which can be assigned to the Si-O-C asymmetric stretching and Si-O-C bonds, respectively.