• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1539-1544
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• 2008

A polymeric micelle, based on the poly(benzyl-L-histidine)-b-poly(ethylene glycol) (polyBz-His-b-PEG) diblock copolymer, was designed as a tumor-specific targeting carrier. The micelles (particle size: 67-80 nm, critical micelle concentration (CMC); 2-3 $\mu$g/mL) were formed from the diafilteration method at pH 7.4, as a result of self-assembly of the polyBz-His block at the core and PEG block on the shell. Removing benzyl (Bz) group from polyBz-His block provided pH-sensitivity of the micellar core; the micelles were physically destabilized in the pH range of pH 7.4-5.5, depending on the content of the His group free from Bz group. The ionization of His group at a slightly acidic pH promoted the deformation of the interior core. These pHdependent physical changes of the micelles provide the mechanism for pH-triggering anticancer drug (e.g., doxorubicin: DOX) release from the micelle in response to the tumor’s extracellular pH range (pH 7.2-6.5).

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.550-553
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• 2000

The polymeric matrices made with poly(D,L-lactide-co-glycolide) were prepared using copolymer of poly(D,L-lactide) and poly(ethylene glycol) for application of drug delivery systems. Catalyst made use of stannous actoate. Particle size were differ greatly$(435.3{\pm}11.2{\sim}2284.1{\pm}188.5)$ that nanoparticle made use of according to solvent of various kinds. Polymer could a sharp distinction with copolymerized among LE-1, LE-2 and LE-3 of PLA and PEG of content that to examine $^1H-NMR$ of copolymer make refine and reprecipitation. Drug delivery effect at PLGA nanoparticle : PLA amount more then proved highly drug delivery amount that each LE-1, LE-2, LE-3, drug and solvent was 40mg, 20mg and 10mg. Drug delivery effect proved higher 20mg that change(10mg, 20mg, 40mg) at drug feeding amount with LE-2. The first a lot of drug proved delivery. LE-3 most lactide content proved much delivery since biodegradable on PLGA copolymer result from lactide. Also biodegradable rate was highest at LE-3 much of lactide content, because influence at biodegradable effect of lactide by inclusive of soft PEG.

• Membrane and Water Treatment
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• 제11권2호
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• pp.159-166
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• 2020

In this study, the performance and antifouling properties of polysulfone (PSf) and polyvinylidene fluoride/polyvinylpyrrolidone (PVDF/PVP) membranes in a membrane bioreactor (MBR) were investigated. The membranes were prepared via phase inversion method, and then characterized by a set of analyses including contact angle, porosity and water flux and applied in a lab-scale MBR system. Soluble microbial product (SMP), extracellular polymeric substance (EPS), FTIR, gel permission chromatography (GPC) and particle size distribution (PSD) analyses were also carried out for MBR system. The results showed that the MBR with PSf membrane had higher hydrophobic organic compounds which resulted in formation of larger flocs in MBR. However, in this MBR had high compressibility coefficient of cake layer was higher (n=0.91) compared to MBR with PVDF/PVP membrane (n=0.8); hence, the fouling was more profound. GPC analysis revealed that compounds with molecular weight lower than 2 kDa are more formed on PSf membrane more than PVDF/PVP membrane. The results of FTIR analysis confirmed the presence of polysaccharide and protein compounds on the cake layer of both membranes which was in good agreement with EPS analysis. In addition, the results showed that their concentration was higher for the cake on PSf membrane.

• 한국분말재료학회지
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• 제18권4호
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• pp.347-358
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• 2011

Two different schemes were adopted to fabricate ordered macroporous structures with face centered cubic lattice of air spheres. Monodisperse polymeric latex suspension, which was synthesized by emulsifier-free emulsion polymerization, was mixed with metal oxide ceramic nanoparticles, followed by evaporation-induced self-assembly of the mixed hetero-colloidal particles. After calcination, inverse opal was generated during burning out the organic nanospheres. Inverse opals made of silica or iron oxide were fabricated according to this procedure. Other approach, which utilizes ceramic precursors instead of nanoparticles was adopted successfully to prepare ordered macroporous structure of titania with skeleton structures as well as lithium niobate inverted structures. Similarly, two different schemes were utilized to obtain disordered macroporous structures with random arrays of macropores. Disordered macroporous structure made of indium tin oxide (ITO) was obtained by fabricating colloidal glass of polystyrene microspheres with low monodispersity and subsequent infiltration of the ITO nanoparticles followed by heat treatment at high temperature for burning out the organic microspheres. Similar random structure of titania was also fabricated by mixing polystyrene building block particles with titania nanoparticles having large particle size followed by the calcinations of the samples.

• 한국분말재료학회지
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• 제23권3호
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• pp.189-194
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• 2016

We report a facile method for preparing KIT-1 mesoporous silicates with two different macroporous structures by dual templating. As a template for macropores, polystyrene (PS) beads are assembled into uniform three dimensional arrays by ice templating, i.e., by growing ice crystals during the freezing process of the particle suspension. Then, the polymeric templates are directly introduced into the precursor-gel solution with cationic surfactants for templating the mesopores, which is followed by hydrothermal crystallization and calcination. Later, by burning out the PS beads and the surfactants, KIT-1 mesoporous silicates with macropores are produced in a powder form. The macroporous structures of the silicates can be controlled by changing the amount of EDTANa4 salt under the same templating conditions using the PS beads and inverse-opal or hollow structures can be obtained. This strategy to prepare mesoporous powders with controllable macrostructures is potentially useful for various applications especially those dealing with bulky molecules such as, catalysis, separation, drug carriers and environmental adsorbents.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1552-1555
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• 2005

We have studied the inkjet patterning of synthesized aqueous silver nano-sol on interface-controlled ITO glass substrate. Furthermore, we designed the conductive ink for direct inkjet patterning on bare ITO glass substrate. The first, the highly concentrated polymeric dispersant-assisted silver nano sol was prepared by variation of molecular weight and control of initial nucleation and growth of silver nanoparticles. The high concentration of batch-synthesized silver nano sol was possible to 40 wt%. At the same time the particle size of silver nanoparticles was below $10{\sim}20nm$. The second, the synthesized silver nano sol was inkjet - patterned on ITO glass substrate. The connectivity and width of fine line depended largely on the wettability of silver nano sol on ITO glass substrate, which was controlled by surfactant. The relationship was understood by wetting angle. The fine line of silver electrode as fine as $50{\sim}100\;{\mu}m$ was successfully formed on ITO glass substrate. The last, the direct inkjet-patternable silver nano sol on bare ITO glass substrate was designed also.

• 대한화학회지
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• 제57권4호
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• pp.439-446
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• 2013

Chitosan (CS) and hydroxypropylmethyl cellulose (HPMC) blend microspheres were prepared by water-in-oil emulsion technique and were loaded with an anti-cancer drug 5-fluorouracil (5-FU). CS-HPMC microspheres were characterized by Fourier transform infrared spectroscopy to confirm the cross-linking reaction. Scanning electron microscopy (SEM) was also used to assess the surface morphology of particles prepared. The quantity of release of 5-FU from the microspheres have been studied in terms of blend composition and amount of cross-linking agent. Differential scanning calorimetry and X-ray diffraction techniques indicated a uniform distribution of 5-FU particles in microspheres, whereas SEM suggested the spherical structure of the microspheres with slight rough surface. The in vitro drug release indicated that the particle size and release kinetics depend upon blend composition, amount of cross-linking agent used and amount of 5-FU present in the microspheres.

• 대한화학회지
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• 제45권3호
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• pp.236-241
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• 2001

$Y_2O_3$: Eu 형광체는 고효율, 열적 화학적 안정성을 갖고 있어서 평판 표시 소자용 적색 형광체로 널리 사용되고 있다. 고분해능과 고효율을 가지는 평판 표시 소자는 작은 크기의 구형 입자를 가진 형광체를 필요로 한다. 본 연구에서는 착체 중합법을 이용하여 100-300nm크기의 $Y_2O_3$ : Eu 형광체를 제조하였고 1족 혹은 2족 원소를 첨가하여 발광특성에 대한 영향을 검토하였다.

• 한국세라믹학회지
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• 제43권9호
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• pp.519-526
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• 2006

A full-factorial design of experiments with three input factors and two levels for each factor including center points was utilized for the preparation and characterization of twelve types of $BaTiO_3$ slips for tape casting. Ceramic powders with different particle sizes, different milling methods such as high energy milling and conventional ball milling, and two types of dispersant with different polymeric species were chosen as input factors in order to investigate their effects on slip and on green tape properties. Tape casting, a small rectangular-shaped K-square preparation, characterization and quantitative data analysis using statistical software were followed. Ceramic powder was the most significant among three input factors for the output responses of slip viscosity and green tape density, showing more favorable results with large particles than with very fine ones. In addition, high energy milling for only 30 min was more efficient than 24h of conventional ball milling in terms of powder dispersion and milling. The optimum condition based on the experimental results was a slip exposed to high energy milling with large ceramic particles along with a methylethyl acetate dispersant.

• 한국결정성장학회지
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• 제9권5호
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• pp.480-485
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• 1999

FED용의 적색 형광체로 Al과 Pr이 첨가된 $SrTiO_3$의 제조와 형광특성에 대하여 연구하였다. 이 형광체는 metallic nitrates, ethylene glycol, citric acid를 출발물질로 하여 polymeric complex를 형성하는 Pechini 법으로 합성하였다. 본 실험에서 합성된 분말의 성장기구는 $900^{\circ}C$를 경계로 서로 다른 경향을 보이고 있으며, $600^{\circ}C$의 저온에서도 $SrTiO_3$상이 형성됨을 확인하였다. 또한 빛 발광특성의 경우는 Pr 이온에 의한 359 nm에서의 여기 스펙트럼과 저전압 음극선 발광의 경우 617 nm에서 최대 피크를 갖고 575 nm와 650 nm 사이에서 적색의 발광 스펙트럼이 관찰되었다. Pechini 법으로 합성된 $SrTiO_3$:Al, Pr 형광체의 경우 FED의 적색 형광체에 적용될 수 있을 것이다.