• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.204-204
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• 1999

The plasma source ion implantation(PSII) technique which is a method using high negative voltage pulse in plasma system has the potential to change the surface properties of polymer. PSII technique increase the surface free energy by introducing polar functional groups on the surface so that it improves reactivity, hydrophilicity, adhension, biocompatability, etc. However, the mobility of polymer chains enables the modified surface layers to adapt their composition to interfacial force. This hydrophobic recovery interrupts the stability of modified surfaces to keep for the long time. In this study, poly(methyl methacrylate)(PMMA), poly(2-hydroxyethyl methacrylate)(PHEMA), and polu(2-hydroxypropyl methacylate)(PHPMA) for contact lens application, were modified to improve the wettability with PSII technique and were investigated the surface stabilities. Polymer film was prepared with solution casting(3 wt.% solution) and was annealed at 11$0^{\circ}C$ under vacuum oven to remove solvent completely and to eliminate physical ageing. The thickness of the film measured by scanning electron microscopy (SEM) and surface profilometer was about 10${\mu}{\textrm}{m}$. Polymers were treated with different kinds of gases, pulse frequency, pulse with, pulse voltage, and treatment time. Even though PMMA, PHEMA, and PHPMA have similar repeat unit structure, the optimal treatment conditions and the tendency to hydrophobic recovery were different. PHPMA, more hydrophilic polymer than PMMA and PHEMA showd better wettability and stability after mild treatment. Surface tensions were obtained by water and diiodomethane contact angle measurements to monitor the relation between hydrophobic recovery and polymer structure. Different ion species in plasma change the polar component and dispersion component of polymer surface. For better wettability surface, the increase of polar component was a dominant factor. We also characterized modified polymer surfaces using x-ray photoelectron spectroscopy(XPS), secondary ion mass spectrometry(SIMS), Fourier Transform infrared spectroscopy(FT-IR), and SEM.

• 청정기술
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• 제11권4호
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• pp.205-211
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• 2005

마이크로렌즈 어레이의 제작은 매우 다양한 재료와 방법이 제안되어 지고 있으나, 폴리머를 이용한 사출법은 광학적 특성, 내충격성, 가공성, 경량화 및 환경친화성 등의 장점으로 주목 받고 있다. 사출법 템플레이트를 제작하기 위한 PR(Photo-Resist) reflow법은 형상제어가 용이하고 대량생산과 정밀가공의 측면에서 효율적이어서, 집적화가 용이하고 공정을 줄일 수 있는 장점을 갖게 되어 매우 환경친화적이다. 그러나 마이크로렌즈 어레이의 사출성형은 사용되는 폴리머재료의 성질에 따라 성형에 어려움이 있는 것으로 알려져 있다. 본 연구에서는 이와 같은 성형의 어려움을 극복하기 위한 방법으로 급가열/급냉각 사출을 통하여 마이크로렌즈 어레이를 제작하고 특성을 이해하였다. 템플레이트의 급격한 온도상승과 고온에서의 모양이 냉각으로 인한 변형이 없도록 급속히 냉각시켜 줌으로서 마이크로렌즈 어레이의 사출성형을 구현 하였다. PC(Poly-Cabon ate)와 PMMA(Poly-Methyl-Meth-Acrylate)를 비교하여, PMMA가 낮은 용융점에 의해 성형성이 우수함을 확인하였다. 사출시 압력과 속도를 변수로 마이크로렌즈 어레이의 제작을 위한 사출조건을 도출하였다.

• 한국정밀공학회지
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• 제32권3호
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• pp.299-305
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• 2015

In this paper, we propose a simple and low-cost fabrication method of polymer microlens using solvent-vapor-assisted reflow (SVAR). Metal molds for replication of polymer were fabricated using micro milling and the cylindrical shape of polymer was imprinted using hot-embossing process. The cylindrical shape of polymer was changed to hemispherical lens shape by SVAR. The characteristics of fabricated microlens were evaluated according to the condition of SVAR such as temperature and time. The focal length of polymer microlens could be controlled more easily in low-temperature and long-time condition than in high-temperature and short-time condition. That is, the level of concentrated light to focal point could be improved through the control of temperature and time. Also, we confirmed that toluene was more appropriate solvent than acetone in fabrication of PMMA polymer microlens using SVAR.