• Journal of Pharmaceutical Investigation
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• 제34권5호
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• pp.407-411
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• 2004

New formulations of amlodipine maleate tablet have been investigated to enhance the stability of the drug against light and humidity. Three kinds of amlodipine maleate tablets were prepared. One is prepared by previously known formulation (formulation C), the others were by new formulations using hydrophilic polymer $(Opadry^{\circledR})$ coated granules (formulations A and B). Amlodipine maleate powder was coated with $Opadry^{\circledR}$ to produce the coated granules and it was mixed with other excipients to produce the tabletting mass of new formulations A and B. Dissolution rate of newly formulated tablets was over 80% within 10 minutes in 0.01 M HCl medium, and its dissolution pattern was similar to that of $Norvasc^{\circledR}$ tablet. After 6 months storage under accelerated conditions, residual drug contents of tested formulations (A and B) were not significantly different from formulation C, ranging from 96.2 to 100.4%. Meanwhile, dissolution amount of formulation C was significantly reduced compared to that of formulation A (p<0.05), showing formulation A was more stable than unprotected formulation C at the accelerated conditions. Results of appearance, hardness and disintegration remained unchanged during stability study. In conclusion, it showed that the new formulations had enhanced the stability characteristics and hydrophilic coating technique was an alternative and promising method to improve the stability of amlodipine maleate tablet.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.103-104
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• 2007

Nanometer-scaled polymer beads, such as polystyrene beads, were used as nanometer fabrication materials due to their some advantages such as self-assembled monolayer, nanometer scaled size and excellent compatibility with silicon based devices. Thus, the investigation on these properties of polymer beads was required. It is difficult to control the array of polystyrene beads on silicon substrate. In this study, we investigated the condition of selective array of polystyrene beads on nanometer-scaled hydrophilic surface which was obtained by APS coating. A tilting method was used to array the polystyrene beads selectively on the substrate. The polystyrene beads could be arrayed selectively by this method. From these results, we verified that there are possibilities to fabricate unique tools for the nanometer-scaled electrical devices.

• 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.

• 한국가시화정보학회지
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• 제16권2호
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• pp.16-22
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• 2018

This study investigates dynamic wetting behaviors of a water droplet placed on surfaces with different wettability and nano-structures. Hydrophobic and hydrophilic properties on as-received silicon wafers were prepared by fabricating thin films of hydrophobic polymer and hydrophilic nanoparticles via layer-by-layer coating. Dynamic advancing contact angle of droplets on the prepared surfaces was measured at various moving velocities of triple contact line with a high-speed video camera. As advancing velocity of triple contact line increased, dynamic advancing contact angle on the as-received silicon and hydrophobic surfaces sharply increased up to $80^{\circ}$ in the range of order of mm/sec whereas the SiO2 nanoparticle-coated hydrophilic surface maintained low contact angles of about $30^{\circ}$ and then it gradually increased in the velocity range of order of hundred mm/sec. The improved dynamic wetting ability observed on the nanostructured hydrophilic surface can benefit the performance of various phase-change heat transfer phenomena under forced convective flow.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.129-129
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• 2006

Conventional solvent-based polyurethane (PU) is well established for wide applications, such as textile treatments, surface coating, adhesive and so on. Due to the demands of safety, economic, and environmental protection, the solvent-based PU is restricted and has been phasing out and aqueous-based PU is becoming the world market trend, which is an environmental friendly product. The chemical resistance, physical and mechanical properties of aqueous-based PU are still not competible with solvent-based PU. Because of aqueous-based PU is a linear thermoplastic polymer with lower average molecular weight. Their improvements are normally performed by a post-curing reaction or a polymer hybridization to enhance the polymer cross-linking density. Hybridization of PU with aqueous-based epoxy resin or acrylate emulsion and then cured by a curing agent for improving the performance properties and reducing the cost of aqueous-based PU.Furthermore, a special function is added to aqueous-based PU increasing the application value, for examples, flame retardation, polymeric dyes, hydrophilic and etc.

• 한국산학기술학회논문지
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• 제11권7호
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• pp.2451-2458
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• 2010

고혈압 치료제인 카르베딜롤을 모델약물로 하여 새로운 서방성 방출 제어형 매트릭스 정제를 제조하기 위하여 소수성 서방성 부형제인 Compritol 888 ATO와 친수성 고분자인 hydroxypropyl methyl cellulose (HPMC) 또는 polyethylene oxide (PEO)를 이용하여 방출 제어형 매트릭스 정제를 제조하였다. 카르베딜롤 방출 제어형 매트릭스 정제의 제조 시 Compritol 888 ATO의 비율과 친수성 고분자의 종류 및 비율, hot melt coating coagglutination (HMCC) rocess의 적용 유무에 따른 카르베딜롤의 방출 양상을 위하여 용출시험기를 사용하여 pH 1.2의 인공위액과 pH 6.8의 인공장액에서 24시간 동안 $37^{\circ}C$, 50 rpm으로 용출시험을 실시하였다. 그 결과, HMCC process를 적용한 모든 제제가 약물의 방출 제어에 매우 효과적인 것을 확인하였다. 또한 소수성 서방성 부형제인 Compritol 888 ATO의 비율에 따라 약물의 방출 양상 및 시간이 기존 일반정제에 비하여 약 95%의 용출률을 나타내었으며 24시간까지 지연됨을 확인할 수 있었다.

• 접착 및 계면
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• 제20권4호
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• pp.146-154
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• 2019

본 연구에서는 소수성 PPO 사슬과 친수성 PEO 사슬들이 동시에 존재하고, 반응성 알콕시 실란기를 가지고 있는 알콕시 실란 기능화 양친성 고분자 전구체 (Alkoxysilane-functionalized Amphiphilic Polymer, AFAP)를 합성하여, 이를 TEOS과의 Hydrolysis- Polycondensation 반응에서 분산안정제 및 반응속도 조절제로 이용하여서 유-무기 하이브리드 나노입자가 안정적으로 분산된 졸 (Sol)을 제조하였다. 제조된 Sol에 불소 함유 실란화합물을 혼합·반응하여서 불소함유 유-무기 하이브리드 Sol을 제조하였고, 이를 유리 기재에 코팅하고 저온 경화를 통해 기재위에 경화필름을 형성하였다. 형성된 경화 필름은 AFAP 및 불소 함유 실란화합물의 첨가량, 용매 종류에 따라서 표면 경도 및 발수 특성이 변화하였다. 최적의 용매 및 불소 함유 실란화합물 첨가량에서 태양전지나 디스플레이에 적용가능한 투명하면서도 견고한 유-무기 하이브리드 형태의 코팅필름 형성이 가능하였다.

• 대한치과기공학회지
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• 제29권1호
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• pp.121-131
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• 2007

A preparation process's conditions of aqueous sol which contains anatase-type nano titania particles with photocatalyic properties was established by using Yoldas process, so called, DCS(Destabilization of Colloidal Solution) process in this study. And crystal size change and phase transformation of titania particles in aqueous titania sol depending on reaction conditions was investigated by a light scattering method and XRD analysis of frozen dried powders, respectively. This sol with photo catalytic nano titania particles was used to the following hydrophilic hybrid coating film's fabrication and its properties was evaluated. Subsequently, for coating film using the above mentioned aqueous titania sol, non-aqueous titania sol was prepared without any chemical additives and its time stability according to aging time was investigate. By using the above mentioned aqueous titania sol and non-aqueous sol, a complex oxide coating sol for metal and ceramic substrate and a organic-inorganic hybrid coating sol for polymer substrate was prepared and it's hydrophilicity depending on UV irradiation conditions was evaluated. As a conclusions, the following results were obtained. (1)Aqueous titania sol The average particle size of titania in formed aqueous titania sol was distributed between 20$\sim$90nm range depending on reaction conditions. And the crystal phase of titania powders obtained by frozen drying method was changed from amorphous state to anatase and subsequently transformed to rutile crystal phase and it is attributed to concentration gradient in aqueous sol. (2)Non-aqueous titania sol Non-aqueous titania sol was prepared using methanol as a solvent and a little distilled water for hydrolysis and nitric acid as a catalyst were used. The obtained non-aqueous titania sol was stable at room temperature for 20 days. Additionally, non-aqueous titania sol with addition of chealating reagent such as acethylaceton and ethylene glycol prolonged the stability of sol by six months. (3)Complex sol and hybrid sol with super hydrophilicity The above mentioned aqueous titania sol as a main photocataylic component and non-aqueous titania sol as a binder for coating process was used to prepare a complex sol used for metal, ceramic and wood material substrate and also to prepare the organic-inorganic hybrid sol for polymer substrate such as polycarbonate and polyethylene, in which process APMS(3-Aminopropyltrimethoxysilane), GPTS(3-Glycidoxypropyl-trimethoxysilane) as a hydrophilic silane compound and HEMA(2-Hydroxyethyl methacrylate) as a forming network in hybrid coating film were used. The hybrid coating film such as prepared through this process showed a superhydrophilicity below 1$10^{\circ}$ depending on processing conditions and a pencil's hardness over 6 H.

• 공업화학
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• 제30권5호
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• pp.586-590
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• 2019

The aim of this study was to fabricate a dextran polyelectrolyte multi-layer on a bare metal stent (BMS) and to evaluate bio-physical properties of the layer. Diethylaminoethyl-dextran (DEAE-D) as a polycation and dextran sulfate (DS) as a polyanion were successively coated on the bare metal stent by a well-known layer-by-layer procedure. The morphology of the stent surface and its cell adhesion were studied after each coating step by scanning electron microscopy. The stent showed more blotched and slightly rougher morphology after dextran-DS coating. The contact angle of the DEAE-DS group ($39.5{\pm}0.15^{\circ}$) was significantly higher than that of the BMS group ($45.16{\pm}0.08^{\circ}$), indicating the improvement of hydrophilic. The SMC proliferation inhibition in the DEAE-DS-coated stent group ($20.9{\pm}0.04%$) was stronger than that in the control group ($21.7{\pm}0.10%$ in DS-coated group only). The DEAE-DS coating is desired for stent coating materials with biocompatibility and anti-restenosis effect.

• Advances in nano research
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• 제4권1호
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• pp.15-29
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• 2016

A low cost environmentally benign surface coating binder is highly desirable in the field of material science. In this report, castor oil based hyperbranched polyester/bitumen modified fly ash nanocomposites were fabricated to achieve the desired performance. The hyperbranched polyester resin was synthesized by a three-step one pot condensation reaction using monoglyceride of castor oil based carboxyl terminated pre-polymer and 2,2-bis (hydroxymethyl) propionic acid. Also, the bulk fly ash of paper industry waste was converted to hydrophilic nano fly ash by ultrasonication followed by transforming it to an organonano fly ash by the modification with bitumen. The synthesized polyester resin and its nanocomposites were characterized by different analytical and spectroscopic tools. The nanocomposite obtained in presence of 20 wt% styrene (with respect to polyester) was found to be more homogeneous and stable compared to nanocomposite without styrene. The performance in terms of tensile strength, impact resistance, scratch hardness, chemical resistance and thermal stability was found to be improved significantly after formation of nanocomposite compared to the pristine system after curing with bisphenol-A based epoxy and poly(amido amine). The overall results of transmission electron microscopic (TEM) analysis and performance showed good exfoliation of the nano fly ash in the polyester matrix. Thus the studied nanocomposites would open up a new avenue on development of low cost high performing surface coating materials.