• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.383-388
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• 2000

Multiblock copolymers consisting of poly( g-benzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part (GEG) were synthesized and characterized. GEG polymeric micelles were prepared by the dialysis technique. Particle size distributions based on intensity,volume, and number-average were 22.6 $\pm$ 11.9 nm, 23.5 $\pm$ 4.6 nm, and 23.7 $\pm$ 37 nm, respectively. It was observed that par-ticle size and size distribution of GEG polymeric micelles changed significantly with the choice of initial sol-vent. Transmission electron micrographs (TEM) showed the polymeric micelles to be spherically shaped, with sizes ranging from 20 nm to 40 nm in diameter. Fluorescence spectroscopy measurements suggested that GEG block copolymers wereassociated in water to form polymeric micelles, and the critical micelle concentrations (CMC) value of the block copolymers was 0.0094 g/L. Further evidenceof micelle formation of GEG block copolymers and limited mobility of the PBLG chain in the core ohe micelle was obtained with 1 H NMR in D2O.

• 한국재료학회지
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• 제32권4호
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• pp.193-199
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• 2022

In this study, lenses are fabricated using various nanomaterials as additives to a silicone polymer made with an optimum mixing ratio and short polymerization time. In addition, PVP is added at a ratio of 1 % to investigate the physical properties according to the degree of dispersion, and the compatibility with hydrophobic silicone and the possibility of application as a functional lens material are confirmed. The main materials are SIU as a silicone monomer, DMA, a hydrophilic copolymer, EGDMA as a crosslinking agent, and 2H2M as a photoinitiator. Holmium (III) oxide, Europium (III) oxide, aluminum oxide, and PVP are used. When Holmium (III) oxide and Europium (III) oxide are added based on the Ref sample, the characteristics of the lens tend to be similar overall, and the aluminum oxide shows a tendency slightly different from the previous two oxides. This material can be used as a silicone lens material with various nano oxides and polyvinylpyrrolidone (PVP) acting as a dispersant.

• 멤브레인
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• 제29권6호
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• pp.362-376
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• 2019

본 연구에서는 열유도상분리법(thermally induced phase separation)을 사용하여 제조한 플라워 형태의 단면을 갖는 PVDF [poly(vinylidene fluoride)] 중공사 분리막에 대한 친수화 코팅과 그에 따른 특성평가에 대한 연구를 수행하였다. 연구에 사용한 중공사 분리막은 (주)퓨어엔비텍에서 제조한 PVDF 소재의 분리막이었으며, 친수화 코팅 실험은 PEBAX 1657, 2533, 3533의 공중합체 고분자를 사용하여 농도가 다른 용액을 제조 후 딥 코팅 방법을 이용하여 실시하였다. 친수화 코팅이 된 중공사 분리막은 친수화 정도를 파악하기 위하여 SEM 촬영 및 접촉각 측정을 실시하였다. SEM 촬영 결과 코팅의 농도가 증가하고 코팅횟수가 증가할수록 코팅층의 두께가 두꺼워짐을 확인하였고, 접촉각 측정의 경우 코팅의 농도가 증가하고 코팅횟수가 증가할수록 접촉각이 낮아짐을 확인하였다. 기체 투과 실험 결과 코팅농도가 증가하고 코팅횟수가 증가할수록 산소 기체투과량이 감소하였으며 친수성이 높은 PEBAX 1657로 코팅한 중공사의 기체투과량이 PEBAX 2533과 3533으로 코팅된 중공사보다 낮은 기체투과량을 가짐을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1800-1808
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• 2013

Dual-responsive amphiphilic block copolymers were synthesized by combining enzymatic ring-opening polymerization (eROP) of ${\varepsilon}$-caprolactone (CL) and ATRP of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA). The obtained block copolymers were characterized by gel permeation chromatography (GPC), $^1H$ NMR and FTIR-IR. The critical micelle concentration (CMC) of copolymer was determined by fluorescence spectra, it can be found that with hydrophilic block (PDMAEMA) increasing, CMC value of the polymer sample increased accordingly, and the CMC value was 0.012 mg/mL, 0.025 mg/mL and 0.037 mg/mL for $PCL_{50}$-b-$PDMAEMA_{68}$, $PCL_{50}$-b-$PDMAEMA_{89}$, $PCL_{50}$-b-$PDMAEMA_{112}$, $PCL_{50}$-b-$PDMAEMA_{89}$ was chosen as drug carrier to study in vitro release profile of anti-cancer drug (taxol). The temperature and pH dependence of the values of hydrodynamic diameter (Dh) of micelles, and self-assembly of the resulting block copolymers in water were evaluated by dynamic light scattering (DLS). The result showed that with the temperature increasing and pH decreasing, the Dh decreased. Drug-loaded nanoparticles were fabricated using paclitaxel as model. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) had been explored to study the morphology of the hollow micelles and the nanoparticles, revealing well-dispersed spheres with the average diameters both around 80 nm. In vitro release kinetics of paclitaxel from the nanoparticles was also investigated in different conditions (pH and temperature, etc.), revealing that the drug release was triggered by temperature changes upon the lower critical solution temperature (LCST) at pH 7.4, and at $37^{\circ}C$ by an increase of pH.

• 폴리머
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• 제33권5호
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• pp.485-489
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• 2009

중수소화 폴리스티렌-폴리에틸렌옥사이드 이중블록공중합체(dPS-PEO)로 형성된 미셀의 구조에 대한 온도 의존성을 소각중성자산란(SANS)을 이용하여 조사하였다. SANS 데이터는 코어-쉘 모델의 form factor와 hard-sphere structure factor를 결합하여 분석하였으며, 산란 곡선 맞춤을 이용하여 미셀 응집수와 코로나 반경을 구하였다. 온도가 $25^{\circ}C$에서 $45^{\circ}C$로 증가함에 따라서 미셀 응집수는 229에서 240으로 변화하였으며, 이로 인해 코어 반경이 증가하였다. 그러나, 미셀의 쉘 두께는 6.2 nm에서 5.8 nm로 감소하였다. 이러한 구조적 변화는 온도 증가에 따라서 PEO 블록의 소수성이 증가함으로써 코로나 내의 친수성 그룹 당 수화 부피가 감소하였기 때문이다.

• Journal of Pharmaceutical Investigation
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• 제17권3호
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• pp.111-126
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• 1987

Methyl methacrylate-butyl methacrylate copolymer (MMBM)-dibutyl phthalate (DBP) films were investigated as a potential topical drug delivery system for the controlled release of nitrofurazone. The kinetic analysis of release data indicated that drug release followed a diffusion-controlled granular matrix model, where the quantity released per unit area is proportional to the square root of time. DBP of several hydrophobic plasticizers selected was found to give the highest release of nitrofurazone. However, hydrophilic plasticizers such as propylene glycol and polyethylene glycol 400 had no controlled release properties and acceptable film formation. The effects of changes in film composition, drug concentration, film thickness, pH of release medium, and temperature on the in vitro release of nitrofurazone were analyzed both theoretically and experimentally. The release rate constant (k') was found to be proportional to DBP content, pH, and the temperature of release medium, but independent of film thickness, and drug concentration in a range of 0.1-0.4% by weight. The linear relationship was found to exist between the log k' and DBP content. The release of nitrofurazone from MMBM-DBP (8:2) films was found to be an energy-linked process. Two energy terms were calculated ; the activation energy for matrix diffusion was 13.45 kcal/mole, and the heat of drug crystal solvation was 27.26-29.34 kcal/mole. Observation of scanning electron micrographs and microscopic photographs showed that the incorporation of DBP in films increased markedly the particle size of nitrofurazone dispersed in the film matrix, comparing with the fine dispersion of nitrofurazone in pure MMBM film alone.

• Macromolecular Research
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• 제15권5호
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• pp.437-442
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• 2007

Poly(ethylene glycol) methyl ether (PEG)-poly(${\beta}$-amino ester) (PAE) block copolymers were synthesized using a Michael-type step polymerization, and the construction of pH-sensitive polymeric micelles (PM) investigated. The ${\beta}$-amino ester block of the block copolymers functioned as a pH-sensitive moiety as well as a hydrophobic block in relation to the ionization of PAE, while PEG acted as a hydrophilic block, regardless of ionization. The synthesized polymers were characterized using $^1H-NMR$, with their molecular weights measured using gel permeation chromatography. The $pK_b$ values of the pH-sensitive polymers were measured using a titration method. The pH-sensitivity and critical micelle concentration (CMC) of the block copolymers in PBS solution were estimated using fluorescence spectroscopy. The pH dependent micellization behaviors with various bisacrylate esters varied within a narrow pH range. The critical micelle concentration at pH 7.4 decreased from 0.032 to 0.004 mg/mL on increasing the number of methyl group in the bisacrylate from 4 to 10. Also, the particle size of the block copolymer micelles was determined using dynamic light scattering (DLS). The DLS results revealed the micelles had an average size below 100 nm. These pH-sensitive polymeric micelles may be good carriers for the delivery of an anticancer drug.

• 폴리머
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• 제38권3호
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• pp.293-298
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• 2014

본 연구에서는 방사선을 이용하여 다공성 polytetrafluoroethylene(PTFE) 지지체에 acrylonitrile(AN)과 친수성 작용기를 가진 sodium allylsulfonate(SAS)를 접목시켜 복합 연료전지막의 지지체로 사용되는 친수화 다공성 지지체를 제조하였다. SAS/AN의 몰비율, 단량체 농도, 방사선의 조사선량에 변화를 주어 제조된 지지체의 물성을 평가하였다. 제조된 지지체의 FTIR 분석을 통하여 각 단량체들이 다공성 PTFE 지지체에 성공적으로 그래프팅되었음을 확인하였다. 또한 FE-SEM과 gurley number 측정을 이용하여 그래프트율이 증가할수록 지지체 표면의 기공이 감소하는 것을 관찰하였고, 그래프트율, 접촉각, TBO(toluidine blue O) uptake 분석을 통해 그래프트율이 증가됨에 따라 제조된 지지체의 친수화도가 증가하는 것을 확인하였다.

• 에너지공학
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• 제25권4호
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• pp.176-183
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• 2016

본 연구는 연료전지용 고분자 전해질 막의 성능 향상에 관한 것으로서 연료전지를 구동하기 위해 요구되는 전해질 막의 특성에 대하여 연구하였다. Bis(4-fluorophenyl)phenyl phosphine oxide를 발연 황산을 이용하여 양이온($H^+$)을 전도할 수 있는 술폰산기를 치환시켜 주었다. 친수성 올리고머와 소수성 올리고머를 각각 합성하고, 블록 공중합체는 친수성 올리고머와 소수성 올리고머를 방향족 친핵성 치환반응에 의해 제조하였다. 블록 공중합체의 구조 및 술폰화도(DS)는 $^1H$-NMR, 겔 침투 크로마토그래피 (GPC) 분석에 의해 확인하였다. 열적 안정성은 열중량 분석(TGA)을 통해 확인하였으며, 본 연구에서 제조한 블록 코폴리머는 $200^{\circ}C$ 이상의 온도 조건에서 내열성을 나타내었다. 또한, 이온전도성은 연료전지 전해질 막으로서의 성능을 증명하기 위해 이온전도도 시험을 수행하였다. 제조한 막은 온도가 증가할수록 발달된 이온클러스터의 영향으로 최대 58 mS/cm의 이온전도성을 보였다. 블록 코폴리머의 미세 상 분리의 특성은 AFM분석을 통해 확인하였다.

• 에너지공학
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• 제25권3호
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• pp.66-72
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• 2016

본 연구에서는 술폰화된 sodium 5,5'-carbonylbis(2-fluorobenzene sulfonate) 단량체를 이용하여 친수성 올리고머를 합성한 뒤 소수성 올리고머와 1:1로 공중합반응을 시켜 sulfonated poly(arylene ether ketone) (SPAEK) 공중합체를 합성하였다. 제조한 공중합체의 구조 분석은 $^1H$-NMR, FT-IR, GPC를 사용하여 실시하였고, GPC에서 공중합체의 평균분자량은 $209,700g\;mol^{-1}$, 다분산지수(PDI)는 1.25이었다. 열적 안정성을 확인하기 위하여 TGA 분석을 실시하였고, $200^{\circ}C$이상에서의 열 안정성을 확인하였다. 고분자 전해질 막의 양이온 전도도는 상대습도 100%, $80^{\circ}C$의 온도에서 약 $9.0mS\;cm^{-1}$이었다. 측정된 결과로부터 본 연구에서 제조한 탄화수소계 전해질 막은 술폰화 정도를 증가시키거나 약간의 구조적 변형을 통해 연료전지용 고분자 전해질 막으로 적용 가능할 것으로 기대된다.