• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.635-636
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.525-526
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• 2010

• Macromolecular Research
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• v.17 no.7
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• pp.522-527
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• 2009

A photocrosslinkable polyphosphazene was used for molecular imprinting. We synthesized polyphosphazene (3) having urea groups for complexation with N-carbobenzyloxyglycin (Z-Gly-OH, template) and chalcone groups for cross-linking reaction. As substituents, 4-hydroxycha1cone (1) and N-(4-hydroxyphenyl)-N'-ethylurea (2) were prepared. Choloro groups of poly(dichlorophosphazene) were replaced by the sequential treatment with sodium salts of compounds 1 and 2, and trifluoroethanol. The template molecule was complexed with the urea groups on the polymer chains via hydrogen bonding. A thin polymer film was prepared by casting a solution of the complex of polymer 3 and the template in dimethylformamide on a quartz cell and irradiated with 365 nm UV light to yield a cross-linked film with a thickness of about $16{\mu}m$. The template molecules in the film were removed by Soxhlet extraction with methanol/acetic acid. The control polymer film was prepared in the same manner for the preparation of the imprinted polymer film, except that the template and triethylamine were omitted. In the rebinding test, the imprinted film exhibited much higher recognition ability for the template than the control polymer. We also investigated the specific recognition ability of the imprinted polymer for the template and its structural analogues. The rebinding tests were conducted using Z-Glu-OH, Z-Asp($O^tBu$)-OH, and Z-Glu-OMe. The imprinted film showed higher specific recognition ability for the template and the lowest response for Z-Asp($O^tBu$)-OH.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1917-1921
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• 2008

Ultraviolet-nanoimprint lithography (UV-NIL) is promising technology for cost effectively defining micro/nano scale structure at room temperature and low pressure. In addition, this technology is fascinating because of it's possibility for high-throughput patterning without complex processes. However, to acquire good micro/nano patterns using this technology, there are some challenges such as uniformity and fidelity of patterns, etc. In this paper, we have focused on uniform contact mechanism and performed contact mechanics analysis. The dimension of the flexible sheet to get adequate uniform contact area has been obtained from contact mechanics simulation. Based on this analysis, we have made a uniform pressurizing device and confirmed its uniform pressurized zone using a pressure sensing paper.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.96-101
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• 2017

We have developed a compact desktop-sized nanopatterning system driven by the Roll-to-Roll (R2R) nanoimprinting (NIL) principle. The system realizes the continuous and high-speed stamping of various nanoscale patterns on a large-area flexible substrate without resorting to ponderous and complicated instruments. We first lay out the process principle based on continuous NIL on a UV-curable resin layer using a flexible nanopatterned mold. We then create conceptual and specific designs for the system by focusing on two key processes, imprinting and UV curing, which are performed in a continuous R2R fashion. We build a system with essential components and optimized modules for imprinting, UV curing, and R2R conveying to enable simple but effective nanopatterning within the desktop volume. Finally, we demonstrate several nanopatterning results such as nanolines and nanodots, which are obtained by operating the built desktop R2R NIL system on transparent and flexible substrates. Our system may be further utilized in the scalable fabrication of diverse flexible nanopatterns for many functional applications in optics, photonics, sensors, and energy harvesters.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.55-59
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• 2022

In this paper, we compared the electric field and absorptance of nano particles in nanostructures by amplifying the electric field around the nanoparticles through plasmon resonance and comparing the structure that can increase the absorptance with the nanostructure by using the Finite Different Time Domain (FDTD) simulation. In addition, the width of the nanostructure was adjusted to 240 nm ~ 300 nm, and the light absorptance rate was higher as the gap between the particles was short. In addition, a study was conducted on the formation of nanoparticles and nanostructures on the surface through UV imprint. In order to form particles in the structure, the nano particles were first arranged in the mold used for the fabrication of the structure using spray coating, and then fabricated through UV imprinting. The nanostructure and particles were formed together by scanning electron microscopy.

• KSBB Journal
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• v.14 no.3
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• pp.273-278
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• 1999

The molecularly imprinted polymers(MIPs) synthesized at various polymerization conditions were examined as ibuprofen receptors in terms of binding characteristics. The 4-vinylpyridine polymers had 1.2 times higher adsorption capability for (S)-(+)-ibuprofen than the methacrylic acid polymers. The methacrylic acid polymers synthesized by UV radiation had 1.9 times higher selectivity for (S)-(+)-ibuprofen compared to those by thermal initiation. Effects of various solvents for binding were also examined in this research. According to the Scatchard analysis, the (S)-(+)-ibuprofen artificial receptors had two different kinds of binding sites for (S)-(+)-ibuprofen while having only single kind of binding site for ketoprofen. The binding sites of (S)-(+)-ibuprofen, n were calculated as 4.3~4.9 $\mu$mol/g and the dissociation constants, $K_D$ were 0.68 mM for the specific binding.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.153-153
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• 2012

자연계에는 다양한 생물체들의 표면 구조가 특수한 기능을 갖는 형태로 되어 있다. 이와 같이 특수한 기능을 갖는 생물체들의 표면 구조는 일반적으로 화학적 조성과 표면의 더불어 나노와 마이크로 구조가 혼합되어 있는, 이른바 hierarchical 구조를 보인다. 그 중에서도 표면 초소수성 특성을 보이는 연잎의 표면과 같은 hierarchical 구조는 self-cleaning effect 등의 기능성 표면 제작에 활용이 가능하여 이를 모사하기 위한 연구가 활발히 진행중에 있다. 이에 본 연구에서는 연잎과 같은 초소수성을 띄는 ZnO nano-in-micro hierarchical 구조를 저온 공정을 통하여 다양한 기판에 제작하였다. 이를 위하여 ZnO 나노 입자 분산 레진을 제작하였고 UV imprinting 과 수열합성법을 통하여 마이크로 패턴 상부에 ZnO 나노 입자가 형성된 ZnO nano-in-micro hierarchical 구조를 형성하였다. 제작된 ZnO hierarchical 구조의 젖음 특성은 표면 접촉각이 $160^{\circ}C$이상인 초소수성을 보였으며, 제작 공정에는 고온의 열처리가 수반되지 않아 PET film 등 다양한 기판에 ZnO hierarchical 구조를 제작할 수 있었다.

• Polymer(Korea)
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• v.32 no.2
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• pp.138-142
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• 2008

Molecularly imprinting technology is an effective method to prepare a synthetic material with a high selectivity to a target molecule. In this study, a molecularly imprinted polymer (MIP) was synthesized via UV-polymerization using theophylline and UV-curable polyester-acrylate resin as a template molecule and a crosslinker, respectively. To elucidate the effects of functional monomer type on the performance of the MIP, each MIP was synthesized using mathacrylic acid, acrylic acid, and acryl amide as functional monomers. Each MIP showed higher rebinding capacity to theophylline than its corresponding non-imprinted polymer (NIP). The MIP synthesized using mathacrylic acid as a functional monomer showed the highest rebinding capacity to theophylline. The selectivity of the MIP was investigated using a solution with caffeine having a very similar structure to theophylline. The binding performance of the MIP to theophylline decreased when distilled water was used as a solvent, which has more polarity than chloroform.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.295-295
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• 2014

일반적으로 박막 태양전지의 효율은 박막 종류에 따른 광 흡수율에 의해 결정되며, 이는 증착한 박막의 두께에 의해 결정된다. 증착한 박막의 두께가 두꺼워질수록 광 흡수율은 증가하지만, 박막 두께가 지나치게 두꺼워지면 열화 현상으로 인한 모듈의 효율 감소가 생기므로 적절한 박막의 두께가 요구된다. 특히 a-Si:H의 경우 가시광 영역에서 높은 흡수계수를 가지고 있어서 얇은 박막 두께로도 태양전지의 제작이 가능하지만, 동일한 박막 두께에서 효율을 더욱 향상시키기 위한 다양한 광 포획 기술에 대한 연구가 많이 진행 되고 있다. 본 연구에서는 자외선을 이용한 nano-imprint lithography 기술을 이용하여 a-Si:H 태양전지의 유리기판 위에 pattern을 삽입하여 광 산란 효과를 향상 시키고자 하였다. 또한 유리기판의 굴절률 (n=1.5)과 투명전극의 굴절률 (n=1.9)의 중간 값을 갖는 ZnO nanoparticles (n=1.7)이 분산 된 imprinting resin을 사용함으로써 점진적으로 굴절률을 변화시켜, 최종적으로 a-Si:H 층까지의 광 투과율을 높이고자 하였다. 제작한 기판의 종류는 다음과 같다. 첫 번째 기판으로는 유리기판 위에 ZnO nanoparticles이 분산 된 imprinting resin을 spin-coating 하여 점진적인 굴절률의 변화에 의한 투과도 향상을 확인하고자 하였다. 두 번째 기판으로는 규칙적인 배열을 갖는 micro 크기의 패턴을 형성하였다. 마지막으로는 불규칙한 배열을 갖는 nano 크기와 micro 크기가 혼재 된 패턴을 형성하여 투과도 향상과 동시에 빛의 산란을 증가시키고자 하였다. 후에 이 세가지 종류를 기판으로 사용하여 a-Si:H 기반의 박막 태양전지를 제작하였다. 먼저 제작한 박막 태양전지용 기판의 광학적 전기적 특성을 분석하였다. 유리 기판 위에 형성한 패턴에 의한 roughness 변화를 확인하기 위해 atomic force microscopy (AFM)를 이용하여 시편의 표면을 측정하였다. 또한 제작한 유리 기판 위에 투명 전극층을 형성 후, 이로 인한 전기적 특성의 변화를 확인하기 위해 hall measurement system을 이용하여 sheet resistance, carrier mobility, carrier concentration 등의 특성을 측정하였다. 또한, UV-visible photospectrometer 장비를 이용하여 각 공정마다 시편의 광학적 특성(투과도, 반사도, 산란도, 흡수도 등)을 측정하였고, 최종적으로 제작한 박막 태양전지의 I-V 특성과 외부양자효율을 측정하여 태양전지의 효율 변화를 확인하였다. 그 결과 일반적인 유리에 기판에 제작된 a-Si:H 기반의 박막 태양전지에 비해, ZnO nanoparticles이 분산 된 imprinting resin을 spin-coating 하여 점진적인 굴절률 변화를 준 것만으로도 약 12%의 태양전지 효율이 증가하였다. 또한, micro 크기의 패턴과 nano-micro 크기가 혼재된 패턴을 형성한 경우 일반적인 유리를 사용한 경우에 비해 각각 27%, 36%까지 효율이 증가함을 확인하였다.