• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1999년도 가을 한국섬유공학회 학술발표회 논문집(Proceedings of the Korean Textile Conference)
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• pp.505-508
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• 1999

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권1호
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• pp.9-15
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• 2010

Aim of the study: As an injectable scaffold, MPEG-PCL diblock copolymer was applied in bone tissue engineering. In vivo bone formation was evaluated by soft X-ray, histology based on the rat calvarial critical size defect model. Materials and Methods: New bone formation was evaluated with MPEG-PCL diblock copolymer in rat calvarial critical size bone defect. No graft was served as control. 4, 8 weeks after implantation, gross evidence of bone regeneration was evaluated by histology and soft X-ray analysis. Results: The improved and effective bone regeneration was achieved with the BMP-2 and osteoblasts loaded MPEG-PCL diblock copolymer. Conclusion: It was confirmed that MPEG-PCL temperature sensitive hydrogels was useful as an injectable scaffold in bone regeneration.

• Macromolecular Research
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• 제13권6호
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• pp.467-476
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• 2005

The main objective of this study was to develop and characterize pH-sensitive biodegradable polymeric materials. For pH-sensitivity, we employed three kinds of moieties: 2-amino-3-(lH-imidazol-4-yl)-propionic acid (H), N-[4-( 4,6-dimethyl-pyrimidin-2ylsulfamoyl)-phenyl]succinamic acid (SM), and 2- {3-[ 4-( 4,6-dimethyl-pyrim­idin- 2-ylsulfamoyl)-phenylcarbamoyl]-propionylamino} -3-(3 H - imidazol-4-yl)-propionic acid (SH). The pH -sensitive diblock copolymers were synthesized by ring opening polymerization and coupling reaction from poly(ethylene glycol) (MPEG), $\varepsilon$-caprolactone (CL), D,L-lactide (LA) and pH-sensitive moieties. The pH-sensitive SH molecule was synthesized in a two-step reaction. The first step involved the synthesis of SHM, a methyl ester derivative of SH, by coupling reaction of SM and L-histidine methyl ester dihydrochloride, whereas the second step involved the hydrolysis of the same. The synthesized SM, SHM and SH molecules were characterized by FTIR, $^{1}H$-NMR and $^{13}C$-NMR spectroscopy, whereas diblock copolymers and pH-sensitive diblock copolymer were characterized by $^{1}H$-NMR and GPC analysis. The critical micelle concentrations were determined at various pH conditions by fluorescence technique using pyrene as a probe. The micellization and demicellization studies of pH-sensitive diblock copolymers were also done at different pH conditions. The pH-sensitivity was further established by acid-based titration and DLS analysis.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.276-276
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• 2013

Time-Of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Atomic Force Microscopy (AFM) are the useful instruments to measure nanostructures of material surfaces. Surface pattern formation in blending homopolymer and diblock copolymer films was investigated as a function of film thickness and annealing conditions. In this study, surface structures of blending homopolymer [deuterated polystyrene (Mn 20,000), poly (methyl methacrylate) (Mn 18,000)] and diblock copolymer [Poly (deuteratedstyrene(d8)-b-methyl methacrylate) (Mn 19,500-18,100)] films were observed. The AFM result indicated that the nanostructures and film thickness depended on temperature, concentration and solvent. TOF-SIMS depth profiling was obtained for the lamellar morphology of symmetric dPS-b-PMMA which is found to orient parallel to the surface of the substrate. Elemental and molecular depth profiles measured in the negative ion mode by a Cs+ primary ion beam demonstrate variations in hydrogen, deuterium, carbon, oxygen, hydrocarbons and deuterated hydrocarbons within the diblock copolymer according to the depth.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.50.2-50.2
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• 2007

• Bulletin of the Korean Chemical Society
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• 제16권9호
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• pp.873-885
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• 1995

The local structural and thermodynamical properties of blends A-B/H of a diblock copolymer A-B and a homopolymer H are studied using the polymer reference interaction site model (RISM) integral equation theory with the mean-spherical approximation closure. The random phase approximation (RPA)-like static scattering function is derived and the interaction parameter is obtained to investigate the phase transition behaviors in A-B/H blends effectively. The dependences of the microscopic interaction parameter and the macrophase-microphase separation on temperature, molecular weight, block composition and segment size ratio of the diblock copolymer, density, and concentration of the added homopolymer, are investigated numerically within the framework of Gaussian chain statistics. The numerical calculations of site-site interchain pair correlation functions are performed to see the local structures for the model blends. The calculated phase diagrams for A-B/H blends from the polymer RISM theory are compared with results by the RPA model and transmission electron microscopy (TEM). Our extended formal version shows the different feature from RPA in the microscopic phase separation behavior, but shows the consistency with TEM qualitatively. Scaling relationships of scattering peak, interaction parameter, and temperature at the microphase separation are obtained for the molecular weight of diblock copolymer. They are compared with the recent data by small-angle neutron scattering measurements.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.296-296
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• 2006

Highly temperature stable mesoporous materials have excellent properties and potential applications. Here we show a novel poly(vinyl)silazane-block-polystyrene diblock copolymer, which was synthesized by controlled/living free radical polymerization with reversible addition fragmentation chain transfer (RAFT) route. The obtained diblock copolymer occurs the phaseseparation on the nanoscale to form ordered nanostructure, which is converted to mesoprorous ceramic after heating at 800oC. This route demonstrates the preparation of highly temperature stable mesoporous silicon carbon nitrides (SiCN) ceramic film directed from highly cross-linking poly(vinyl)silazane blocks with high ceramic yield, which is different from previous pathway.

• Macromolecular Research
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• 제13권4호
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• pp.344-351
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• 2005

pH-sensitive block copolymers were synthesized by coupling reaction of sulfamethazine and amphiphilic diblock copolymer, and their micellization-demicellization behavior was investigated. Sulfamethazine (SM), a derivative of sulfonamide, was introduced as a pH responsive moiety while methoxy poly(ethylene glycol)poly(D,L-lactide) (MPEG-PDLLA) and methoxy poly(ethylene glycol)-poly($D,L-lactide-co-{\varepsilon}-caprolactone$) (MPEG-PCLA) were used as biodegradable amphiphilic diblock copolymers. After the sulfamethazine was carboxylated by the reaction with succinic anhydride, the diblock copolymer was conjugated with sulfamethazine by coupling reaction in the presence of DCC. The critical micelle concentration (CMC) and mean diameter of the micelles were examined at various pH conditions through fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. For MPEG-PDLLA-SM and MPEG-PCLA-SM solutions, the pH-dependent micellization-demicellization was achieved within a narrow pH band, which was not observed in the MPEG-PDLLA and MPEG-PCLA solutions. The micelle showed a spherical morphology and had a very narrow size distribution. This pH-sensitive block copolymer shows potential as a site-targeted drug carrier.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.193-193
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• 2006

Fluorescent dyes were encapsulated in the nanometer-sized diblock copolymer micelles to control the fluorescence resonance energy transfer. Since acceptor molecules and donor molecules were effectively isolated in the independent micelles, the energy transfer between donors and acceptors was suppressed by the site isolation, leading to the simultaneous emission from both donor and acceptor molecules.

• 한국진공학회지
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• 제15권4호
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• pp.427-433
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• 2006

자발적인 미세상 분리에 의해 실린더형의 규칙적인 배열을 형성하는 고분자 공중합체와 알루미늄의 양극산화에 의해 실린더형 기공 배열이 형성되는 알루미나 템플레이트를 이용하여 다양한 물질의 나노점 배열을 형성하였다. 펄스형 레이저 기상 증착법을 이용하여 은, 니켈, 산화아연, 실리콘, 코발트 / 백금 나노점 배열을 얻었는데, 나노점의 크기와 배열은 템플레이트의 기공 크기와 배열을 보여주었다. 이러한 템플레이트 기법을 이용하면 나노점의 밀도는 고 분자 공중합체와 알루미나의 경우 각각 $6{\times}10^{11}/cm^2$ 와 $1{\times}10^{10}/cm^2$ 이다. 이중 에르븀이 도핑된 실리콘 나노점과 ZnO 나노점 배열은 PL 측정을 통하여 물질의 광학성질에 관해 알아보았다. 에르븀이 도핑된 실리콘 나노점 배열은 $1.54{\mu}m$에서 강한 빛을 내며 ZnO 나노점 배열은 380 nm 에서 강한 PL 세기를 나타낸다.