• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.161-169
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• 2012

Recently, a study for the functional surface production of super hydrophobic of natural and biomimetic artificial has attracted much attention. To make process methods of super hydrophobic surface has a variety of ways such as lithography, etching, and laser ablation. However, we were used ultra-shot pulse laser ablation process which has the virtue of more environmental friendliness and simple process. In this paper, we were fabricated a multiplicity of super hydrophobic patterns on mold surface(NAK80) using by optimizing the laser processing conditions and it was transferred on PDMS. Also, we measured contact angle super hydrophobic patterns on PDMS. The result showed there is no patterns on PDMS were measured 94 degrees, by contrast, optimized super hydrophobic patterns on PDMS was 157 degrees. Therefore we fabricated super hydrophobic surface on mold. Based on these experimental results, it is possible to mass production using ultra shot pulse laser ablation of super hydrophobic pattern and to be applied for a variety of industries.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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• pp.78-84
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• 1995

Cationic surfactants can be used to modify surface of solids to promote adsorption of hydrophobic organic compounds. This behavior is due to the surfactant forming aggregate structure on the solid surface. Partition coefficients are commonly used to quantify the distribution of organic pollutants between the aqueous and particulate phases of aquatic system Partitioning of hydrophobic compounds to cetyltrimethylammonium bromide ( CTAB ) coated silicate has been investigated as a function of surfactant surface coverage at I=0 and 0.1 ionic strength. Toluene, Xylene, TCI sorption experiments demonstrated that the CTAB coated silicate was able to remove these hydrophobic organic compounds from solution The hydrophobic organic compound with the higher Kow had higher removals than lowest Kow hydrophobic organic compound.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.1-7
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• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Journal of Environmental Science International
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• v.3 no.1
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• pp.57-64
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• 1994

On the basis of the principle of Bratch's electronegativity equalization, we calculated group partial charges and group electronegativities for nonionic surfactants with Pauling's elecoonegativity parameters by using numerical calculation method. From calculated outputs we have investigated structural stability of micelle, characteristics of hydrophilic and hydrophobic groups, and relation between CMC(Critical Micelle Concentraion) and group partial charge and group electronegativity of hydrophilic and hydrophobic groups for nonionic surfactants. We have known that CMC by micelle formation depends upon group partial charge and group electronegativity of hydrophilic and hydrophobic groups for surfactants. Also, the structural stability of micelle in H2O solution is related to the electric double layer by the hydrophilic group of nonionic surfactants with H atoms in water CMC is diminished by the decrease of repeating units in hydrophilic group at constant hydrophobic group and is diminished by the increments of alkyl chains in hydrophobic group at constant hydrophilic group for nonionic surfactants. In conclusion, CMC is diminished because there is no electrostatic repulsion and is diminished of Debye length by the increments of partial charge of hydrophobic group.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.11
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• pp.1237-1245
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• 2012

The effect of hydrophilicity and hydrophobicity of PET fabric on the detergency of particulate soil were investigated as functions of the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. The detergency of the particulate soil was determined by the adhesion of particles to and their removal from fabric, the PET fabric and ${\alpha}-Fe_2O_3$ were used as textile materials and for the model of particulate soil, respectively. The hydrophilic and hydrophobic finish for PET fabric was treated with a polyester, silicone and fluorine organic compound of resin respectively. The adhesion of particulate soil to fabric treated with hydrophobic chemicals were slightly higher but its removal from fabric treated with hydrophobic chemicals was largely higher than fabric treated with a hydrophilic chemical regardless of solution conditions such as the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. Therefore, hydrophobic treatment for fabric had a more positive effect than the hydrophilic treatment on the detergency of particulate soil.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.93-100
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• 2022

This study describes the evaluation results on the effect of soil particle surfaces coated with various hydrophobic conditions on spectral information according to water content. Wettability test and spectral information evaluation test were performed on the hydrophobic coated standard sand. When the standard sand was coated with 1%, 3%, and 5% hydrophobic, the contact angles of sand-water interface were 130°~143°, 129°~144°, and 131°~144°, respectively. This means that the contact angle increased as the degree of hydrophobic coating increased at the same drying time, but the range of the contact angle had the same wettability. This means that the contact angle increases as the hydrophobic coating degree increases at the same drying time, whereas the contact angle range has the same wettability. As a result of spectral information evaluation, the maximum spectral reflectance of the dried sand with hydrophobic condition decreased compared to that of the hydrophilic sand, as the degree of hydrophobic increased. However, the maximum spectral reflectance was increased by increasing the degree of hydrophobic under the same water content conditions.

• Corrosion Science and Technology
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• v.8 no.3
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• pp.103-109
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• 2009

An epoxy coating was designed to give a hydrophobic property on its surface by modifying it with three types of Amino Terminated Polydimethylsiloxane (ATP), and then effects of the modification on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified epoxy coating were examined using FT-IR spectroscopy, hydrothermal cyclic test, and impedance test. The surface of epoxy coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between epoxy and modifier by the modification. The phase separation tendency is more appreciable when modified by ATP with higher molecular weight ATP at higher content. Water transport behavior of the modified epoxy coating decreased more in that with higher hydrophobic surface property. The resistance to localized corrosion of the modified epoxy coated carbon steel was well agreed with its water transport behavior and hydrophobic tendency.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.620-624
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• 2011

In recent years, the study of self-assembly peptide used in drug delivery system has been attracted great interest from scientists. In the category are self-assembly peptides in the structure either with one hydrophobic surface and another hydrophilic or a hydrophobic head and a hydrophilic tail. Here, we focus on a novel designed peptide EYK with double amphiphilic surfaces, investigating on the capability of peptide as a carrier for hydrophobic compound model pyrene. The fluorescence data presented the dynamic process of the transfer, showing that the pyrene was in the crystalline form in peptide solution, and molecularly migrated from its peptide encapsulations into the membrane bilayers when the peptide-pyrene suspension was mixed with liposome vesicles. The results indicated that the peptide EYK could stabilize hydrophobic pyrene in aqueous solution and delivered it into EPC liposome as a potential carrier.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.671-674
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• 2008

We investigate the slippage effect in a micro-channel depending on the surface characteristics; hydrophilic, hydrophobic, and super-hydrophobic wettabilities. The micro-scale grooves are fabricated on the vertical wall to make the super-hydrophobic surfaces, which enable us visualize the flow fields near walls and directly measure the slip length. Velocity profiles are measured using micro-particle image velocimetry (Micro-PIV) and compared those in the hydrophilic glass, hydrophobic PDMS, and super-hydrophobic PDMS micro-channels. To directly measure the velocity in the super-hydrophobic micro-channel, the transverse groove structures are fabricated on the vertical wall in the micro-channel. The velocity profile near the wall shows larger slip length and, if the groove structure is high and wide, the liquid meniscus forms curves into the valley so that the wavy flow is created after the grooves.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.921-927
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• 1999

In this study, the defrosting behaviors according to the surface characteristics in the fin-tube heat exchanger is experimentally examined. It is found that the draining rate of the hydrophilic and hydrophobic heat exchangers are evenly dispersed during defrosting, compared with that of the bare one. It is caused by the high density frost for the hydrophilic heat exchanger, and surface characteristic for the hydrophobic heat exchanger, respectively. The rest period of the hydrophilic and hydrophobic heat exchangers are shorter and their weight of residual water are smaller than those of the bare heat exchanger The hydrophilic and hydrophobic heat exchangers are more effective than the bare one in terms of defrosting efficiency, and the hydrophobic heat exchanger is better than the hydrophilic one.