• Fashion & Textile Research Journal
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• v.15 no.3
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• pp.461-466
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• 2013

Synthetic fiber materials were developed due the desire of consumers for high-quality, high-performance and comfort. A high functionality of synthetic fiber can be obtained through surface treatment that can improve hydrophilic properties, color depth after dyeing and adhesion properties. These advantages create added-value. Hydrophobic properties are an important feature to create added-value (such as hydrophilic properties). One side processing is a method of imparting to contrary function on the front and rear side. In this study, fluorine-coated Nylon/PU blended fabric was treated on only one side with a low-temperature plasma treatment; subsequently, the contact angles decreased by increasing the time and intensity of the plasma treatment. The contact angle of the untreated surface and the treated surface was different. It a showed a difference in the properties of both surfaces. Tensile strength and stiffness decreased by increasing the time and intensity of the plasma treatment. However, plasma treatment did not significantly change the tensile strength and stiffness on both surfaces of the fabric. SEM photographs showed the surface of fluorine-coated fabric and the etching surface by using plasma treatment on the fabric. Plasma treatment was confirmed not to affect the physical properties of the fabric.

• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.345-360
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• 2019

Polymer Electrolyte Membrane Fuel Cells (PEMFC) is one of the leading advanced energy conversion technology for the use in transport. It generates water droplets through the catalytic processes and dispenses the water through the gas-flowed microchannels. The droplets in the dispensing microchannel experience g-forces from different directions during the operation in transport. Therefore, this paper reviews the computational modelling topics of droplet dynamics behaviour specifically for three categories, i.e. (i) the droplet sliding down a surface, (ii) the droplet moving in a gas-flowed microchannel, and (iii) the droplet jumping upon coalescence on superhydrophobic surface; in particular for the parameters like hydrophobicity surfaces, droplet sizes, numerical methods, channel sizes, wall conditions, popular references and boundary conditions.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1331-1335
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• 2011

We report the results of the characterization of Cu oxide thin films deposited by radio frequency (r.f.) magnetron sputtering at different annealing temperatures. The deposited Cu oxide thin films were investigated by scanning electron microscopy, spectroscopic ellipsometry, X-ray diffraction, atomic force microscopy, Xray photoelectron spectroscopy, and contact angle measurements. The thickness of the films was about 180 nm and the monoclinic CuO phase was detected. The $CuO_2$ and $Cu(OH)_2$ phases were grown as amorphous phase and the ratio of the three phases were independent on the annealing temperature. The surface of Cu oxide films changed from hydrophilic to hydrophobic as the annealing temperature increased. This phenomenon is due to the increase of the surface roughness. The direct optical band gap was also obtained and laid in the range between 2.36 and 3.06 eV.

• Polymer(Korea)
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• v.29 no.1
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• pp.1-7
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• 2005

Interpenetrating polymer network (PN) is a mixture of network polymers. The characteristics of IPN material is the control of morphology during the IPN synthesis. By controlling the relative kinetics of chemical reaction (as well as gellation) and phase separation, the morphology of IPN can be controlled to obtain materials with nano-scale domain and also the co-continuous phase. Other important advantage is the fact that the morphology is permanent due to the presence of the physical interlocking between the networks. The combination of hydrophilic polyurethane and hydrophobic polystyrene in IPN form provides enhanced blood compatibility due to the co-existence of the hydrophilic and hydrophobic domains in nano-scale on the surface. The reaction temperature, reaction pressure and the degree of crosslinking were varied during the IPN synthesis and the morphology and blood compatibility of the resulting IPN materials were studied.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.470-479
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• 2018

The rice blast pathogen Magnaporthe oryzae is a global threat to rice production. Here we characterized RHO2 gene (MGG_02457) that belongs to the Rho GTPase family, using a deletion mutant. This mutant ${\Delta}Morho2$ exhibited no defects in conidiation and germination but developed only 6% of appressoria in response to a hydrophobic surface when compared to the wild-type progenitor. This result indicates that MoRHO2 plays a role in appressorium development. Furthermore, exogenous cAMP treatment on the mutant led to appressoria that exhibited abnormal morphology on both hydrophobic and hydrophilic surfaces. These outcomes suggested the involvement of MoRHO2 in cAMP-mediated appressorium development. ${\Delta}Morho2$ mutation also delayed the development of appressorium-like structures (ALS) at hyphal tips on hydrophobic surface, which were also abnormally shaped. These results suggested that MoRHO2 is involved in morphological development of appressoria and ALS from conidia and hyphae, respectively. As expected, ${\Delta}Morho2$ mutant was defective in plant penetration, but was still able to cause lesions, albeit at a reduced rate on wounded plants. These results implied that MoRHO2 plays a role in M. oryzae virulence as well.

• Membrane Journal
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• v.27 no.1
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• pp.92-103
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• 2017

In this study, electrochemical performance of the hydrophilized separator for the lithium ion battery is studied. The polyolefin based material used as the separator for the lithium ion battery is hydrophobic, and the electrolytic solution using a carbonate-based organic solvent is hydrophilic. Therefore, the polyolefin separator is hydrophilized using various hydrophilic polymers because lithium ion battery uses an aqueous electrolyte solution. In order to evaluate change of the coated separator, the performances of separator in terms of surface morphology, porosity and the wettability are investigated. Finally, the resistance and the ionic conductivity of separator coated with lithium ion are measured to evaluate the performance of lithium ion battery. Separator coated with PMVE shows good hydrophilicity and excellent ionic conductivity because the porosity of the separator is maintained. We can confirm that this property makes potential candidates for lithium ion battery.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.61-64
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• 2011

Matrix Assisted Laser Desorption/Ionization-Time-of-Flight mass spectrometry (MALDI-TOF-MS) is the most widely used MS technique for glycan analysis. However, the poor point-to-point and sample-to-sample reproducibility becomes a limit in glycan biomarker research. A prespotted MALDI plate which overcomes the large crystal formation of 2,5-dihydroxybenzoic acid (DHB) has been developed and applied for glycan analysis. A homogeneous matrix coated surface without a crystal structure was formed on a hydrophilic/ hydrophobic patterned surface using a piezoelectric device. The reproducible MALDI-TOF-MS data have been presented using MALDI imaging of beer glycan as well as serum glycan eluted from 10% and 20% ACN elution fractions. The glycan profile from the serum glycan by MALDI-TOF-MS with a DHB prespotted plate was highly conserved for 10 different spectra and the coefficient of variations of significant ion peaks of MALDI data varies from 3.59 to 19.95.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.24-24
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• 2018

One of the challenges in tissue engineering is the design of optimal biomedical scaffolds, which can be governed by topographical surface characteristics, such as size, shape, and direction. Of these properties, we focus on the effects of nano - to micro - sized hierarchical surface. To fabricate the hierarchical surface structure on poly(${\varepsilon}$-caprolactone) (PCL) film, we employed a nano/micro-casting technique (NCT) and modified plasma process. The micro size topography of PCL film was controlled by sizes of the micro structures on lotus leaf. Also, the nano-size topography and hydrophilicity of PCL film were controlled by modified plasma process. After the plasma treatment, the hydrophobic property of the PCL film was significantly changed into hydrophilic property, and the nano-sized structure was well developed, as increasing the plasma exposure time and applied power. The surface properties of the modified PCL film were investigated in terms of initial cell morphology, attachment, and proliferation using osteoblast-like-cells (MG63). In particular, initial cell attachment, proliferation and osteogenic differentiation in the hierarchical structure were enhanced dramatically compared to those of the smooth surface.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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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.

• Journal of Adhesion and Interface
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• v.25 no.1
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• pp.157-161
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• 2024

Amphiphilic gold nanoparticles, synthesized by the simultaneous binding of hydrophilic and hydrophobic ligands on their surfaces, find diverse applications in energy, bio, optical, electronic technologies, and various other fields. Particularly, these amphiphilic gold nanoparticles possess both hydrophilic and hydrophobic characteristics, enabling them to activate interface at the interface of immiscible fluids and form organized structures. The surface properties of gold nanoparticles play a crucial role in influencing the behaviors of amphiphilic gold nanoparticles at the interface of two fluids. Therefore, this study investigated the adsorption behaviors of gold nanoparticles at the organic solvent-water interface based on the surface characteristics of amphiphilic gold nanoparticles and the type of organic solvents. It was observed that the amount of adsorbed gold nanoparticles at the interface increased with the length of hydrocarbon chains in hydrophobic ligands and increased with shorter hydrocarbon chains in the organic solvent. Furthermore, using the Langmuir isotherm model, the study confirmed the formation of a monolayer by amphiphilic gold nanoparticles and obtained significant thermodynamic parameters simultaneously.