• 공업화학
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• 제21권2호
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• pp.200-204
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• 2010

고체 표면의 성질은 물질의 사용을 결정하는데 있어서 중요하다. 그래서 고분자 박막을 사용하여 표면을 개질시켜 표면층의 물리적, 화학적 성질을 제어하는 방법이 떠오르고 있다. 본 연구에서는 기판 표면과 고분자 간의 화학적 derivatization 없이 광화학 반응을 통하여 간단하고 효과적인 방법으로 고체 표면위에 고분자 박막을 흡착하여 표면을 개질시키는 방법을 설명하였다. 실리콘 웨이퍼에 스핀 코팅으로 형성된 광반응성이 있는 P4VP 박막을 이용하여 다른 고분자를 얹혀 UV 노광을 조사하여 벤질 라디칼 moieties 반응으로 고정하였다. 광화학 반응의 결과, UV 가교가 일어난 고분자는 P4VP 박막에 고정되어 지고, 반응이 일어나지 않은 부분은 초음파 세척으로 제거할 수 있다. 고정된 박막의 두께는 UV 노광 시간과 고분자의 분자량에 상관하여 형성되며, 광화학 반응으로 고정되기 때문에 photolithography 공정으로 마이크론 패턴 형성이 가능하다.

• 폴리머
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• 제33권3호
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• pp.263-267
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• 2009

d-PMMA(deuterated poly(methyl methacrylate)) 박막 표면의 친수성을 향상시키기 위해 산소 플라즈마에 노출시켰다. 이 때 모든 조건은 동일하며, 플라즈마에 대한 노출 시간만을 0초에서 180초까지 변화를 주어 노출 시간에 대한 영향을 접촉각과 X-ray 반사율 장치, 중성자 반사율 장치, XPS(X-ray photoelectron spectroscopy)를 이용해 조사하였다. 노출 시간이 증가할수록 물 접촉각은 작아지며, 산소의 조성은 커짐을 확인함으로써 산소의 조성이 친수성 향상에 큰 영향을 미치는 것을 확인할 수 있었다. 또한, X-ray 반사율 장치를 이용해 얻은 에칭률을 통해서 d-PMMA 박막에 대한 산소 플라즈마의 노출 시간에 따른 물리적 특성을 연구하였으며, X-ray 반사율과 중성자 반사율, 그리고 XPS 측정 결과로부터 산소와 탄소의 조성뿐만 아니라 수소의 조성까지도 얻음으로써 플라즈마 처리된 박막의 화학적 성질을 보다 자세히 연구할 수 있었다.

• KSTLE International Journal
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• 제7권1호
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• pp.14-17
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• 2006

In this paper, we report on the replication of surface topography of natural leaf of Lotus onto thin polymeric films using a capillarity-directed soft lithographic technique. PDMS molds were used to replicate the surface. The replication was carried out on poly(methyl methacrylate) (PMMA) film coated on silicon wafer. The patterns so obtained were investigated for their friction properties at micro-scale using a ball-on-flat type micro-tribo tester, under reciprocating motion. Soda lime balls (1 mm diameter) were used as counterface sliders. Friction tests were conducted at a constant applied normal load of $3000{\mu}N$ and speed of 1mm/s. All experiments were conducted at ambient temperature ($24{\pm}1^{\circ}C$) and relative humidity ($45{\pm}5%$). Results showed that the patterned samples exhibited superior tribological properties when compared to the silicon wafer and non patterned sample (PMMA thin film). The reduced real area of contact projected by the surfaces was the main reason for their enhanced friction property.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.6.2-6.2
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• 2011

Block copolymer (BCP) self-assembly in a film geometry has recently been the focus of increased research interest due to their potential use as templates and scaffolds for the fabrication of nanostructured materials. The phase behavior in a thin film geometry that confines polymer chains to the interfaces will be influenced by the interfacial interactions at substrate/polymer and polymer/air and the commensurability between the equilibrium period (L0) of the BCP and the total film thickness. We investigated the phase transitions for the films of block copolymers (BCPs) on the modified surface, like the order-to-disorder transition (ODT) by in-situ grazing incidence small angle x-ray scattering (GISAXS) and transmission electron microscopy (TEM). The selective interactions on the surface by a PS-grafted substrate provide the preferential interactions with the PS component of the block, while a random copolymer (PS-r-PMMA) grafted substrate do the balanced interfacial interactions on the surface. The thickness dependence of order-to-disorder behavior for BCP films will be discussed in terms of the surface interactions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1353_1354
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• 2009

The OTFT devices had inverted staggered structures of Au/pentacene/ppMMA/ITO on PET substrate. The overall device performances of the flexible devices such as the operating voltage, the field effect mobility, the on/off ratio and the off current are somewhat worse than those of devices fabricated on glass substrates. Pentacene/ppMMA OTFT benchmarks (mobility, sub-threshold slope, on/off ratio) were comparable to that of solution cast PMMA, but below average when compared to other polymer gate dielectrics. However, threshold and drive voltages were among the lowest reported for a polymer gate dielectric, and surpassed only by ultra-thin SAM gate dielectrics.

• Macromolecular Research
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• 제15권7호
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• pp.688-692
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• 2007

The hydrogen-bonding induced alternating multilayer thin films of dendrimers and block copolymer micelles were demonstrated. The block copolymer micelles derived from amphiphilic poly(2-ethyl-2-oxazoline)block-$poly({\varepsilon}-carprolactone)$ (PEtOz-PCL) in aqueous phase have a core-shell structure with a mean hydrodynamic diameter of 26 nm. The hydrogen bonding between the PEtOz outer shell of micelle and the carboxyl unit of poly(amidoamine) dendrimer of generation 4.5 (PAMAM-4.5G) at pH 3 was utilized as a driving force for the layerby-layer alternating deposition. The multilayer thin film was fabricated on the poly(methyl methacrylate) (PMMA) thin film spin-coated on silicon wafer or glass substrate by the alternate dipping of PEtOz-PCL micelles and PAMAM dendrimers in aqueous solution at pH 3. The formation of multilayer thin film was characterized by using ellipsometry, UV-vis spectroscopy, and atomic force microscopy. The PEtOz outer shell of PEtOz-PCL micelle provided the pH-responsive hydrogen bonding sites with peripheral carboxylic acids of PAM AM dendrimer. The multilayer thin film was reversibly removed after dipping in aqueous solution at $pH{\geq}5.6$ due to dissociation of the hydrogen bonding between PEtOz shell of PEtOz-PCL micelle and peripheral carboxyl units of PAMAM dendrimer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.532-537
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• 2007

Nano imprint lithography(NIL) is a cost-efficient, high-throughput processing technique to transfer nano-scale patterns onto thin polymer films. Polymers used as the resist include UV cured resins as well as thermoplastics such as polymethyl-methacrylate(PMMA). In this study, an analytic investigation was performed for the NIL process of transferring nano scale patterns onto polymeric films. Process optimization calls for a thorough understanding of resist flow during the process. We carried out 2D and 3D numerical analyses of resist flow during NIL process. The simulation incorporated continuum-hypothesis and the effects of surface tension were taken into account. For a more effective prediction of free surface, fixed grid scheme with the volume of fluid (VOF) method were used. The simulation results were verified with experimental results qualitatively. And the parametric study was performed for various process conditions.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.247-247
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• 2006

Chemical and physical synthesis routes were combined to prepare macroporous thin films of semiconducting metal-oxides such as $CaCu_{3}Ti_{4}O_{12}\;and\;TiO_{2}$ by sputtering onto (PMMA) microsphere templated substrates. Subsequently, the colloidal templates were removed by thermal decomposition. The remaining inorganic films comprised a monolayer of hollow hemispheres with diameter commensurate with that of the microspheres. This unique morphology increases the surface area and reduces the interfacial area between film and substrate. Consequently, the surface activity is markedly enhanced while deleterious interfacial effects between film and substrate are significantly reduced. Both effects are highly advantageous for gas sensing applications.

• 한국진공학회지
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• 제18권5호
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• pp.372-376
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• 2009

현대 반도체 공정에서 일정한 패턴을 생성하기 위하여 리소그래피(Lithography) 공정을 이용하고 있으나 선폭의 감소로 인하여 기존 UV를 이용한 PR(Photoresist) 이외에 e-beam을 이용한 PMMA(Polymethyl methacrylate) 리소그래피에 대한 관심이 높아지고 있다. 또한 리소그래피에 의하여 생성된 패턴은 이후 세정 공정에서 잔류물을 제거하는 과정에서 패턴 붕괴를 일으키게 되는데 이러한 패턴 붕괴에 대한 방어력은 패턴 형성 물질의 탄성력(Elastic modulus)과 비례하는 것으로 알려져 있다. 이 논문에서 우리는 PMMA의 soft-baking 이후 Hardness(H)와 Elastic modulus(Er)의 변화를 압입력을 25 uN에서 8,500 uN으로 134.52 uN 간격으로 증가시키며 측정하였다. 또한 이 실험에서 Hardness(H)와 Elastic modulus(Er)는 Hysitron사의 Triboindenter를 이용하여 측정하였고 압입팁은 Berkovich 팁을 사용하였다.

• Macromolecular Research
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• 제16권4호
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• pp.373-378
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• 2008

A simple chemical fixation method for the fabrication of layer-by-layer (LbL) polyelectrolyte multilayer (PEM) has been developed to create a large area, highly uniform film for various applications. PEM of weak poly-electrolytes, i.e., polyallylamine hydrogen chloride (PAH) and poly(acrylic acid)(PAA), was assembled on polymer substrates such as poly(methyl methacrylate)(PMMA) and polycarbonate (PC). In the case of a weak polyelectrolyte, the fabricated thin film thickness of the polyelectrolyte multilayers was strongly dependent on the pH of the processing solution, which enabled the film thickness or optical properties to be controlled. On the other hand, the environmental stability for device application was poor. In this study, we utilized the chemical fixation method using glutaraldehyde (GA)-amine reaction in order to stabilize the polyelectrolyte multilayers. By simple treatment of GA on the PEM film, the inherent morphology was fixed and the adhesion and mechanical strength were improved. Both surface tension and FT-IR measurements supported the chemical cross-linking reaction. The surface property of the polyelectrolyte films was altered and converted from hydrophilic to hydrophobic by chemical modification. The possible application to antireflection coating on PMMA and PC was demonstrated.