• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.49-52
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• 2004

New hydrophobic alumina nanoparticles were synthesized from alumina powders which were hydrophilic nano-agglomerates with diameters from ${\mu}m$ to mm by surface modification. The synthesized hydrophobic alumina nanoparticles which were retreated with Oleic acid were analyzed by Fourier transform infrared spectrophotometer and transmission electron microscopy. Then transformer oil containing surface-modified alumina naonparticles were synthesized. The synthesized hydrophobic alumina nanoparticles were well-dispersed in transformer oil. The coefficient of viscosity and dielectric strength of the Nano-transformer oil were investigated with viscometer and high voltage experiment device. In this study, the thermal conductivity of Nano-transformer oil was investigated to reduce the oil temperature of transformer by transient hot-wire method.

• 한국가시화정보학회지
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• 제10권1호
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• pp.21-26
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• 2012

Hydrophobic characteristics of high temperature metal surface were investigated by high-speed visualization of water droplet impact. An aluminum plate was used as the sample plate and the initial diameter of a water droplet was 2 mm. Transient behavior of a single droplet impinging on the surface with and without heating was captured by using a high speed camera running at 4,000 frames per second. The Leidenfrost phenomenon was demonstrated for the case of $300^{\circ}C$ surface temperature, however there was no rebounding of droplet on the cold plate due to hydrophilic nature. The experimental results show that the shape evolution of a droplet impinging on the surface varies with the Weber number, i.e. the ratio of impact inertia to capillary force. The overall water-repellent characteristics of the heated surface was very similar to that of the super hydrophobic surfaces.

• 대한의용생체공학회:의공학회지
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• 제15권1호
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• pp.51-56
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• 1994

Protein adsorption on the polyurethane surface was modelled by a modified random sequential adsorption(RSA) process. In this model, polyurethane surface was modelled as a mixed domain of hydrophobic and hydrophilic parts which was implemented by a 2 dimensional $150{\times}150$ lattice in the computer. Protein adsorption was simulated using a small box which represents a particle of the protein, and polyurethane lattice by considering their hydrophobic interaction. In order to validate the model, we perfonned fibrinogen adsorption on polyurethane surface. Isotherms of the adsorbed protein were calculated and compared to the experimental data. The protein adsorption on the polyurethane surface could be well described using this computer model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.249-250
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• 2010

• 멤브레인
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• 제33권1호
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• pp.1-12
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• 2023

본 총설은 소수성 불소수지계 분리막의 표면 개질에 대한 개론으로 다양한 표면 개질 방법 및 그 연구 결과를 중점적으로 서술하였다. PTFE로 대표되는 불소수지계 고분자 분리막은 막 증류, 유수 분리, 기체 분리를 포함한 다양한 막 분리 공정에서 사용되어왔다. PTFE 막은 내화학성, 내열성, 높은 기계적 강도와 같은 뛰어난 물성에도 불구하고 소수성 표면 특성으로 인해 기술 적용의 확장에 제한적이다. 친수성 향상을 위해 습식 화학법, 친수성 고분자 코팅, 플라즈마 처리, 조사, 원자층 증착과 같은 다양한 PTFE 표면 개질 방법을 이용하며 이를 통해 불소수지계 분리막의 응용분야가 확장될 수 있다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.11-15
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• 1997

We used the photoreactive poly(allylamie) (PPA) as the hydrophilic membrane to control the release of drug from polyurethane(PU). PPA was covalently bonded onto PU surface through the highly reactive nitrene intermediate upon UV light irradiation $(3.3mW/cm^2)$ at 254nm for 5min. Thus the release rate of rifampicin from PU surface was controlled. To know the characteristics of PU surface bonded with PPA, we measured the ATR-FTIR, ESCA, Static Contact Angle and SEM. From these, we suggest that PPA as a hydrophilic membrane is enable to control the release rate of a hydrophobic drug from polymer without the change of bulk property.

• 한국염색가공학회지
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• 제4권4호
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• pp.110-116
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• 1992

For the modification of PET surface, Perfluoropropene and Methyl alcohol were LT-plasma polymerized on the PET fabrics as thin films by means of 13.56 MHz radio frequency generator. The surface properties of PET fabrics were modified from hydrophobic to hydrophilic by application of the postplasma reaction of thin films. The evidence of the modification was identified by observation of the presence of hydroxy group in IR spectrum and the evaluation of degree of hydrophilicity was performed by measuring frictional static voltage of PET fabric with cotton fabric. For the case of modification by PFP, the result performed at the condition of 25 W, 70 m torr has shown to be effective, and for MeOH, result performed at the condition of 25 W, 100 m torr effective. The effect of hydrophilic surface modification of MeOH plasma polymer was superior to that of PFP-plasma polymer.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.449-449
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• 2011

We reported the direct effect of intrinsic surface energy of dry adhesive material to the Van der Waals and capillary forces contributions of the total adhesion force in an artificial gecko-inspired adhesion system. To mimic the gecko foot we fabricated tilted nanohairy structures using both lithography and ion beam treatment. The nanohairy structures were replicated from Si wafer mold using UV curable polymeric materials. The control of nanohairs slanting angles was based on the uniform linear argon ion irradiation to the nanohairy polymeric surface. The surface energy was studied utilizing subsequent conventional oxygen ion treatment on the nanohairy structures which resulted in gradient surface energy. Our shear adhesion test results were found in good agreement with the accepted Van der Waals and capillary forces theory in the gecko adhesion system. Surface energy would give a direct impact to the effective Hamaker constant in Van der Waals force and the filling angle (${\varphi}$) of water meniscus in capillary force contributions of gecko inspired adhesion system. With the increasing surface energy, the effective Hamaker constant also increased but the filling angle decreased, resulting in a competition between the two forces. Using a simple mathematical model, we compared our experimental results to show the quantitative contributions of Van der Waals and capillary forces in a single adhesion system on both hydrophobic and hydrophilic surfaces. We found that the Van der Waals force contributes about 82.75% and 89.97% to the total adhesion force on hydrophilic and hydrophobic test surfaces, respectively, while the remaining contribution was occupied by capillary force. We also showed that it is possible to design ultrahigh dry adhesive with adhesion strength of more than 10 times higher than apparent gecko adhesion force by controlling the surface energy and the slanting angle induced-contact line of dry adhesive the materials.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.188-194
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• 2024

This paper introduces an optimized oxygen (O₂) plasma surface treatment technique to enhance sphere lithography on hydrophobic photoresist surfaces. The focus is on semiconductor manufacturing, particularly the creation of finer structures beyond the capabilities of traditional photolithography. The key breakthrough is a method that makes substrate surfaces hydrophilic without altering photoresist patterns. This is achieved by meticulously controlling the O₂ plasma treatment duration. The result is the consistent formation of nano and microscale patterns across large areas. From an academic perspective, the study deepens our understanding of surface treatments in pattern formation. Industrially, it heralds significant progress in semiconductor and precision manufacturing sectors, promising enhanced capabilities and efficiency.

• 한국물환경학회지
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• 제20권6호
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• pp.708-713
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• 2004

This study was performed to investigate the variations of hydrophilic and hydrophobic organic matter fractions in soluble organic matter according to livestock wastewater treatment by ionized gas and coagulation effect to these fractions after ionized gas contact. As a result of experiment, because of ionized gas contact, particle in the surface of livestock wastewater was more smaller and the result was consisted of particle size analysis and the amount of small size was increased. Also, we confirmed that organic matters in livestock wastewater by ionized gas contact were removed. The relation equation between ionized gas contact time(X) and $TCOD_{cr}$(Y) was shown as yscale(y)=3.748-0.431* xscale(X). That between ionized gas contact time(X) and $TCOD_{cr}$(Y) was yscale(y)=3.283-0.463* xscale(X). As respects the HPL(hydrophilic matter)and HPO(hydrophobic matter) fractions of raw in livestock wastewater treatment plant, HPL fraction was 53.2% and HPO fraction was 46.8%. But, HPO fraction according to ionized gas treatment was increased at 30min and after that time, HPL fraction was increased. Also, when we performed coagulation process after ionized gas treatment of raw wastewater, the removal efficiency of organic matter was the highest at 30min of ionized gas treatment because of the variation of HPL and HPO fractions in organic matter by ionized gas. In coagulation process following after ionized gas process, HPO was removed more effective than HPL.