• KSBB Journal
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• 제22권3호
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• pp.146-150
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• 2007

Poly (3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] 미립구를 용매증발법으로 제조하였다. 3.9 mol% 4HB 조성의 P(3HB-co-4HB)를 Ralstonia eutropha의 유가식 배양으로부터 합성하였다. 계면활성제의 농도 및 종류(Tween 80, sodium dodecylsulfate, polyvinyl alcohol), 분산안정제 (Acacia)의 첨가, 고분자 및 모델 약물 (bovine serum albumin)의 농도 등이 미립구 입자 크기에 미치는 효과 및 in vitro 약물 방출 특성을 조사하였다. 평균 입자크기는 분산 안정제 첨가시 감소하였으며, 계면활성제, 약물 및 고분자의 농도가 증가할수록 증가하였다. 약물 방출량은 입자 크기가 감소할수록 증가하였다.

• 한국응용과학기술학회지
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• 제12권2호
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• pp.29-39
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• 1995

The phase separated structure and the electro-optical properties of the (polymer/liquid) crystal : LC) composite film strongly depended on the weight fraction of LC in it. The continuous LC phase was formed in a three-dimensional polymer network when the LC weight fraction was above 40wt%. The aggregation structure of the composite film could be controlled by controlling the solvent evaporation velocity during the film preparation process. The smaller LC domains or channels were formed in the case of the faster solvent evaporation velocity. The composite film exhibited reversible light scattering-light transmission switching upon electric field -OFF and -ON states, respectiverly. The light scattering properties of the composite film strongly depended on the spatial distortion of the nematic directors as well as the mismatch in refractive indices between matrix polymer and LC.

• Mass Spectrometry Letters
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• 제7권3호
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• pp.79-83
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• 2016

We prepared solid dispersion formulations of quercetin to enhance its solubility and dissolution rate. Various quercetin-loaded solid dispersion were tested with quercetin, poloxamer 407, and carrier such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol 8000 (PEG 8000), and polyvinylpyrrolidone K40 (PVP K40) using solvent evaporation and freeze drying methods in terms of both the aqueous solubility and the dissolution rates of quercetin. The solubility of quercetin as its solid dispersion formulations was markedly improved compared with that of quercetin powder. Especially, highest solubility of quercetin was observed when HPMC was used as a carrier. The cumulative dissolution of quercetin within 360 min from solid dispersion composed of quercetin, poloxamer 407, and HPMC was 8.8-fold higher than the dissolution of pure quercetin. The results of powder X-ray diffraction (XRD) and scanning electron microscope (SEM) indicated that quercetin transformed from a crystalline to an amorphous form through the solid dispersion formulation process. These results suggest that the solid dispersion formulation of quercetin with poloxamer 407 and HPMC could be a promising option for enhancing the solubility and dissolution rate of quercetin.

• Archives of Pharmacal Research
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• 제19권1호
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• pp.30-35
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• 1996

Poly(l-lactic acid)(PLLA) microspheres loaded with ampicillin sodium (AMP-Na_, .betha.-lactam antibiotic, were prepared by a w/o/w multiple emulsion-solvent evaporation method. The amounts of each component in three phases (inner water phase, organic phase, and outer water phase) wre carefully examined in the preparation of PLLA microspheres. The stirring rate, another preparation parameter, was also investigated for study on the effect of mechanical stress on the drug loading and morphology of PLLA microspheres. Most of the preparation parameters had a great influence on the drug loading, surface morphology and size distribution of PLLA microspheres. PLLA microspheres with 15.89 w/w% drug loading were subjected to the in vitro release experimet. The release of ampicillin sodium was constant at a rate of 1.68 $mug/ml/day$ per 1 mg of microspheres for 18 days initial burst effect.

• Macromolecular Research
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• 제14권3호
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• pp.359-364
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• 2006

Di-block copolymers composed of two biocompatible polymers, poly(ethylene glycol) and poly(D,L-lactide), were synthesized by ring-opening polymerization for preparing polymer vesicles (polymersomes). Emulsion solvent evaporation method was used to fabricate the polymersomes. Scanning electron microscope (SEM) images confirmed that polymersomes have a hollow structure inside. Confocal laser microscope and optical microscope were also used to verify the hollow structure of polymersomes. Polymersomes having various sizes from several hundred nanometers to a few micrometers were fabricated. The size of the polymersomes could be readily controlled by altering the relative hydrodynamic volume fraction ratio between hydrophilic and hydrophobic blocks in the copolymer structure, and by varying the fabrication methods. They showed greatly enhanced stability with increased molecular weight of PEG. They maintained their physical and chemical structural integrities after repeated cycles of centrifugation/re-dispersion, and even after treatment with surfactants.

• 한국분말재료학회지
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• 제18권2호
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• pp.112-121
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• 2011

This study investigated the effect of solvent on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid and compared the alloy particles fabricated by three different methods (PWE in liquid, PWE in Ar, plasma arc discharge), for high temperature oxidation-resistant metallic porous body for high temperature soot filter system. Three different solvents (ethanol, acetone, distilled water) of liquid were adapted in PWE in liquid process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. The alloy powder synthesized by PWE in ethanol has good particle size and no surface oxidation compared to that of distilled water. Since the Fe-based alloy powders, which were fabricated by PWE in Ar and PAD process, showed surface oxidation by TEM analysis, the PWE in ethanol is the best way to fabricate Fe-based alloy nano powder.

• 멤브레인
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• 제29권1호
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• pp.61-65
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• 2019

이방성 입자는 독특한 물리적 특성 때문에 다양한 분야에서 발표되고 있다. 여기서, 이방성 도토리구조 나노 입자를 제조하기 위해 새로운 동적 상분리 방법이 도입된다. 동적 상분리 방법은 용제 증발 및 무용제에 의한 침전으로 구성된다. 하부층은 비용매 희석제로서 물을 공급함으로써 제어되며, 상부층의 상분리는 휘발성 용매의 확산 및 증발에 의존한다. 이 상태에서, 도토리 형 입자가 제조되었다. 물이 채워진 밀폐된 상자(자발적 상분리)하에서, 단분산 폴리스틸렌 입자가 합성되었다. 동적 상분리와 자발적 상분리가 공존할 때, 캡과 입자의 크기가 변경되었다. 또한, 폴리스틸렌 용액의 부피는 입자 형상에 영향을 미친다. 독특한 구조가 다양한 응용 분야에 활용될 수 있기 때문에 멤브레인 기반의 제어된 물 공급과 같은 첨단 기술이 개발되면 단분산의 도토리와 같은 입자가 제조될 수 있을 것이다.

• 한국인쇄학회지
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• 제22권2호
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• pp.199-211
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• 2004

The drying speed of gravure ink are very fast because of evaporation drying type. The gravure ink are fitly selected variety resin and solvent for a wide range printing are adopted. Moreover, after-manufacture handling is necessary to various purposes. Though composition of gravure ink are same those of another printing ink, the viscosity of it are vary low compare with another printing inks. As property of variety printed matters, improvement of performance of printing layer and suitable after-manufacture handling, the more research of gravure ink are to be continue for development of printing technology. Generally, the gravure ink are made up resin, pigment, solvent and additive. Especially solvent are fitly selected for solution of resin, viscosity, and drying speed. Furthermore, it tis care of bad smell of remaining resin, poison and danger of fire of it. Because of the prevention of air pollution as restriction deflation of solvent, custody of dangerous object and improvement of work environment as labor safety hygiene and fire-low, the environment restriction of printing business become strict. This study has purpose of development of gravure ink of involved 30% below of alcohol is used for PVC film printing.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.107-114
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• 2003

This study investigated the effect of 2-methoxy ethanol (2-Me) non-solvent as additive included in casting solution. Macroporous polymer membranes were prepared by using polyethersufone (PES)/N-methyl-2-pyrrolidone (NMP)/2-Me casting solution and water coagulant. The phase separation co-process of the vapor-induced phase separation (VIPS) and liquid-induced phase separation (LIPS) were used by means of membrane preparation method. The pore size and pore size distribution were controlled with additive (non-solvent), and measured with Automated Perm Porometer. By increasing additive (non-solvent) in the casting solution, the membranes produced changed from finger structure to sponge structure. That is due to the different diffusion rates. At slow diffusion process, sponge-like structure was formed and at fast diffusion process, finger-like structure was formed. Also relative humidity, evaporation time, temperature of casting solution and coagulation bath etc. had effects on the pore size distribution and the porosity of the membrane.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.418-422
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• 2005

By introducing spin-coating method to the evaporation induced self-assembly (EISA) process, a simple and reproducible route in controlling the mesophase of silica thin films has been developed for the first time in this work. When a comparatively solvent-rich Si-sol (The atomic ratio of TEOS : F127 : HCl : $H_2O$ : EtOH = 1 : 0.006 : 0.2 : 9.2 : 30) was used as coating solution, the mesophase of resultant silica films was selectively controlled by adjusting the spin-on speed. The cubic mesophase has been obtained from the coating at a low rpm, such as 600 rpm, while the 2-D hexagonal mesophase is formed at a high rpm, such as 2,500 rpm. At a medium coating speed, a mixture of cubic and hexagonal mesophase has been found in the fabricated films. The present results confirm that the evaporation rate of volatile components at initial step is critical for the determination of mesopore structures during the EISA process.