• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1522-1528
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• 2008

The morphogenetic behavior of a tropical marine Yarrowia lipolytica strain on hydrophobic substrates was studied. Media containing coconut oil or palm kernel oil (rich in lauric and myristic acids) prepared in distilled water or seawater at a neutral pH supported 95% of the cells to undergo a transition from the yeast form to the mycelium form. With potassium laurate, 51 % of the cells were in the mycelium form, whereas with myristate, 32% were in the mycelium form. However, combinations of these two fatty acids in proportions that are present in coconut oil or palm kernel oil enhanced the mycelium formation to 65%. The culture also produced extracellular lipases during the morphogenetic change. The yeast cells were found to attach to the large droplets of the hydrophobic substrates during the transition, while the mycelia were associated with the aqueous phase. The alkane-grown yeast partitioned more efficiently in the hydrophobic phases when compared with the coconut oil-grown mycelia. A fatty acid analysis of the mycelial form revealed the presence of lauric acid in addition to the long-chain saturated and unsaturated fatty acids observed in the yeast form. The mycelia underwent a rapid transition to the yeast form with n-dodecane, a medium-chain aliphatic hydrocarbon. Thus, the fungus displayed a differential behavior towards the two types of saturated hydrophobic substrates.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.262-262
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• 2010

We introduce a novel and efficient strategy for producing free-standing functional films via photo-crosslinking and electrostatic layer-by-layer (LbL) assembly, which can allow the buildup of hydrophilic multilayers onto hydrophobic surfaces. Hydrophobic multilayers were deposited on ionic substrates by a photo-crosslinking LbL process using photo-crosslinkable polymers. The photo-crosslinked surface was converted to an anionic surface by excess UV light irradiation. This treatment allowed also the stable adhesion between metal electrode or cationic polyelectrolyte and hydrophobic multilayers. After dissolving the ionic substrates in water, the formed free-standing films exhibited unique functionalities of inserted components within hydrophobic and/or hydrophilic multilayers.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1515-1518
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• 2009

Hydrophobic treatments were conducted for different kinds of substrates, glass substrate, silicon wafer and plastic substrate. Ar-$CH_4$ gas mixture was used as a discharge gas for the hydrophobic treatment. The change of the contact angle before and after treatment was measured and compared. Time evolution of the contact angle change after hydrophobic treatment was investigated.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.97-108
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• 2000

A Gram-type negative bacteria that can utilize crude oil as the sole source of carbon and energy was isolated from an activated sludge of a local sewage treatment plant and identified tentatively as belonging to the genus Acinetobacter. The isolate could degrade n-alkanes and unidentified hydrocarbons in crude oil and utilize n-alkanes, hydrophobic substrates, as sole carbon and energy sources. n-Alkanes from tridecane (Cl3) to triacontane (C30) in crude oil were degraded simultaneously with no difference in degradation characteristics between the two close odd and even numbered alkanes in carbon numbers. The linear growth of the isolate and the degradation characteristics of Pr-alkanes suggested that the transport of substrates from the oil phase to the site where the substrates undergo the initial oxidation in microorganism might be the rate limiting in the biodegradation process of crude oil constituents. The remainder fraction of substrates after cultivation was considered to reflect the hydrocarbon inclusions in the cell mass, characteristics in Acinetobacter species, and to control the transport of substrates from crude oil phase. On the basis of the results, the isolate was considered to play an important role in the degradation study of hydrophobic environmental pollutants.

• Bulletin of the Korean Chemical Society
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• v.3 no.1
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• pp.34-36
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• 1982

N-Methacryloyl-L-histidine and N-methacryloyl-L-histidine methyl ester were synthesized and polymerized to obtain polymeric catalysts with different functions. In the presence of each of these polymers the solvolytic reactions of p-nitrophenyl acetate (PNPA), 3-nitro-4-acetoxybenzoic acid(NABA), 3-acetoxy-N-trimethylanilinium iodide(ANTI) and 3-nitro-4-decanoyloxybenzoic acid(NDBA) were performed in 20% aqueous ethanol. For the purpose of comparison the low molecular weight analogs(LMWA's), L-histidine, L-histidine methyl ester and N-acetyl-L-histidine were also subjected to catalyze the solvolyses of above substrates. In the solvolysis of PNPA the polymeric catalysts exhibited lower activities than the LMWA's. However the ionic substrates, NABA and ANTI were solvolyzed at anomalous rate by polymeric catalyst, indicating that electrostatic effects are operative in the catalysis by polymers. Furthermore in the solvolysis of hydrophobic monomer NDBA, polymeric catalysts exhibited highly enhanced activities compared with the LMWA's implying that hydrophobic interaction can be the most important contribution to the high catalytic activity of imidazole-containing polymers.

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

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1553-1555
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• 2008

Super-hydrophobic treated Polyimide film was used as a flexible substrate for developing a new method of metallization. Hydrophilic patterns were fabricated by IN irradiation through shadow mask. Patterned super-hydrophobic substrate was dipped into a bath containing silver nano ink Silver ink was only coated on hydrophilic patterned area. Metal lines of $600{\mu}m$ pitch were fabricated successfully. However, their thickness was too thin to serve as interconnection. To overcome this problem, iterative dipping was conducted. After repeating five times, the thickness of silver metal lines were increased to over than $2{\mu}$. After heat treatment of silver lines, their resistivities were reduced to order of $30{\mu}{\Omega}$-cm the similar level of values reported in other literatures. So, a new method of metallization has high potential for application of RFID antenna and flexible electronics substrates.

• Journal of Powder Materials
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• v.20 no.2
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• pp.120-124
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• 2013

This study is carried out to develop the new process for the fabrication of ultra-fine electrodes on the flexible substrates using superhydrophobic effect. A facile method was developed to form the ultra-fine trenches on the flexible substrates treated by plasma etching and to print the fine metal electrodes using conductive nano-ink. Various plasma etching conditions were investigated for the hydrophobic surface treatment of flexible polyimide (PI) films. The micro-trench on the hydrophobic PI film fabricated under optimized conditions was obtained by mechanical scratching, which gave the hydrophilic property only to the trench area. Finally, the patterning by selective deposition of ink materials was performed using the conductive silver nano-ink. The interface between the conductive nanoparticles and the flexible substrates were characterized by scanning electron microscope. The increase of the sintering temperature and metal concentration of ink caused the reduction of electrical resistance. The sintering temperature lower than $200^{\circ}C$ resulted in good interfacial bonding between Ag electrode and PI film substrate.

• Rapid Communication in Photoscience
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• v.4 no.1
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• pp.19-21
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• 2015

Zeolite is an ideal host material for encapsulating nano-size metal catalyst species because of its defined microporous structure, prominent adsorption/condensation properties, high surface area, chemical/thermal stability, and transparency to light. In this study, $TiO_2$ photocatalyst was incorporated in highly hydrophobic Y zeolite and its photocatalytic activity was examined in the photocatalytic oxidation of olefins under UV-light irradiation using molecular oxygen as an oxygen source. $TiO_2$ nanoparticles incorporated in hydrophobic Y zeolite exhibited a markedly enhanced photocatalytic activity compared with bare $TiO_2$ owing to its excellent affinity toward organic moieties, which facilitates the mass transfer of organic substrates and allows them to efficiently access to the neighboring active $TiO_2$ surface.

• Nano
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• v.13 no.10
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• pp.1850120.1-1850120.9
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• 2018

Two-dimensional poly(dimethylsiloxane) (PDMS) films with wavy patterns were studied in order to investigate reversible and irreversible wetting effects. Pre-strained, surface oxidized layers of PDMS were used to form relieved wavy geometries, on which hydrophobic functionalization was carried out in order to produce irreversible wetting effects. Wavy-patterned PDMS films showed time-dependent reversible wetting effects. The degree of surface wettability could be tuned by the choice of wavy groove geometries. And the groove geometries were controlled via $O_2$ plasma treatment and mechanical pre-straining. The pre-strained, buckled PDMS films were applied to the fabrication of hydrophobic polystyrene nano-patterns using colloidal self-assembly, where the colloids were arrayed in two-dimensional way. The wavy polystyrene films were found to be more hydrophobic relative to flat polystyrene films. The grooving methodology used in this study could be applied to enhancing the hydrophobicity of other types of polymeric thin films, eliminating the need for chemical treatment.