• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2007년도 추계학술발표대회 및
• /
• pp.72.1-72.1
• /
• 2007

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2007년도 추계학술발표대회 및
• /
• pp.48.2-48.2
• /
• 2007

• 한국유변학회:학술대회논문집
• /
• 한국유변학회 2001년도 춘계 학술발표회 논문집
• /
• pp.15-18
• /
• 2001

• Macromolecular Research
• /
• 제11권6호
• /
• pp.437-443
• /
• 2003

A series of alternating and alternating block copolycarbonates containing the constituent groups of polysulfone was synthesized through a multi-step solution condensation method. For the regulation of block length, monodisperse oligomers were prepared by using a large excess of the bisphenols and were subsequently incorporated into the copolymer chains. Separating the unreacted bisphenols from the oligomers by dissolution/precipitation steps took advantage of solubility differences. The structures of the monomers, oligomers, and copolymers were characterized and confirmed by GPC, NMR spectroscopy, mass spectrometry, and elemental analysis. Monodispersity of the oligomers, which is critical for control over the block length in the copolymers, was confirmed by GPC and mass spectrometry. Of the two constituent groups of the polysulfone, the sulfone linkage stiffens the polycarbonate copolymer chain, while the ether linkage softens it.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 추계학술대회
• /
• pp.327-330
• /
• 1996

Poly(L-leucine)(PLL)/poly(ethylene oxide)(PEO)/poly (L-leucine)(PLL) block copolymers were synthsized by polymerization of L-leucine N-carboxyanhydride with diamine-terminated PEO for possibility of wound dressing which may have several advantages such as 1) increase of solubility, 2) control of biodegradation, 3) absorption of body fluid. 4) non-immunogenic effect than PLL homopolymer wound dressing aleady commercialized. Water content increased with an increase of PEO content in the block copolymer due to the hydrophilicity of PEO. Release of silver sulfadiazine(AgSD) from AgSD loaded wound dressing increased with an increase of PEO content in the block copolymer. It was found that the number of Pseudomonas aeruginosa decrease with an increase of PEO content due to the fast release of antibacterial agents with an increase of PEO content in the block copolymer.

• Macromolecular Research
• /
• 제10권2호
• /
• pp.85-90
• /
• 2002

Poly (ethylene oxide)/polylatide/poly(ethylene oxide) (PEO/PL/PEO) tri-block copolymers, which each block is connected by ester bond, were synthesized by coupling reaction of PL with PEO in the presence of pyridine. PL/PEO/PL tri-block copolymer was synthesized by ring opening polymerization of L-lactide initiated by PEO in the presence of stannous octoate. Degradation behavior of the copolymers was investigated in a pH 7.4 phosphate buffer saline (PBS) at 37$\pm$1 $^{\circ}C$. Gel permeation chromatography (GPC) and $^1$H-nuclear magnetic resonance (NMR) were used to monitor the change of mass loss, molecular weight and composition of copolymers. In hydrolytic degradation, the PEO/PL/PEO tri-block copolymer with high PEO contents affected the increase of its mass loss, and resulted in the decrease of its molecular weight as well as PEO composition. However, when PL/PEO/PL and PEO/PL/PEO tri-block copolymers had similar PEO contents, PEO/PL/PEO decreased faster in molecular weight and PEO composition than PL/PEO/PL.

• 폴리머
• /
• 제26권5호
• /
• pp.582-588
• /
• 2002

DL-lactide의 단점을 개선할 목적으로 개환중합법으로 촉매로서 diethylzinc (ZnEt$_2$)를 사용하여, poly(ethylene oxide) (PEO)를 세그먼트로서 도입한 블록공중합체를 합성하였다. 그 결과 DL-lactide에 대한 PEO세그먼트의 첨가비가 30% 이상에서는 조성비가 급격히 증가하였으며, 이들 공중합체를 캐스트법에 의해 필름으로 제작하여 6$0^{\circ}C$에서 2.5배 연신하여 인장실험을 실시하였다. 모든 공중합체 필름은 PDLLA에 대한 PEO에스테르 첨가비의 증대에 따라 탄성율이 저하되는 것이 관찰되어 세그먼트 도입에 의한 유연성의 증대를 확인하였으며 유연성이 요구되는 의용재료로서의 기대를 높였다.

• 한국산학기술학회논문지
• /
• 제18권11호
• /
• pp.88-93
• /
• 2017

다양한 응용분야를 가진 국부적인 표면플라즈몬 공명 특성을 손쉽게 제어할 수 있는 기술 개발은 매우 중요하다. 또한, 금속 나노입자의 형태, 크기, 그리고 조합에 관한 세심한 조사는 공명특성과 금속 나노구조의 관계를 이해하는데 매우 유용하다. 본 논문은 블록공중합체 마이셀 박막필름으로부터 얻어진 금속나노입자 배열에 따른 국부적인 표면플라즈몬의 공명특성에 관한 연구이다. 우선 전통적인 방법의 블록공중합체 리소그라피를 통해 두 가지 다른, 점 형태 및 링 형태, 금 나노입자를 제조하였다. 그 다음 은거울 반응을 통하여 금 나노입자위에 은이 둘러 쌓이도록 금/은 이중금속 나노구조를 구현했다. 금속 나노 구조체 조절을 위해 에탄올 전처리, 은거울 반응 시간, 블록공중합체의 제거 유무 등의 공정변수를 변화시켰다. 초기 금 나노입자가 잘 제조된 경우 항상 금나노입자 표면에 적절히 은이 잘 형성되었고, 이는 UV-Vis 실험에서 각 금속나노 입자의 고유 플라즈몬 밴드인 금 525nm, 은 420nm에서 각각 나타났다. 하지만 최초 적은 양의 금 나노입자가 제조되었을 경우 은 도금 속도가 빨라져서, 초기 금 나노입자의 표면을 은이 완전히 덮었으며, 이는 UV-Vis 실험에서 금의 플라즈몬 밴드는 나타나지 않고, 은의 고유 플라즈몬 밴드만 420nm에서 나타났다. 블록공중합체로부터 미리 합성된 금나노입자 위에 은을 도금하는 방법은 국부적인 표면플라즈몬 특성을 면밀히 조사하는데 매우 유용하다.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.6.1-6.1
• /
• 2011

Nanoscale block copolymer (BCP) patterns have been pursued for applications in sub-30 nm nanolithography. BCP self-assembly processing is scalable and low cost, and is well-suited for integration with existing semiconductor fabrication techniques. However, one of the major technical challenges for BCP self-assembly is limited tunability in pattern geometry, dimension, and functionality. We suggest methods for extending the degree of tunability by choosing highly incompatible polymer blocks and utilizing solvent vapor treatment techniques. Siloxane BCPs have been developed as self-assembling resists due to many advantages such as high etch-selectivity, good etch-resistance, long-range ordering, and reduced line-edge roughness. The large incompatibility leads to extensive degree of pattern tunability since the effective volume fraction can be easily manipulated by solvent-based treatment techniques. Thus, control of the microdomain size, periodicity, and morphology is possible by changing the vapor pressure and the mixing ratio of selective solvents. This allows a range of different pattern geometry such as dots, lines and holes and critical dimension simply by changing the processing conditions of a given block copolymer without changing a polymer chain length. We demonstrate highly extensive tunability (critical dimension ~6~30 nm) of self-assembled patterns prepared by a siloxane BCP with extreme incompatibility.

• 한국수소및신에너지학회논문집
• /
• 제27권6호
• /
• pp.660-669
• /
• 2016

A fluorinated-sulfonated, hydrophobic-hydrophilic copolymer was planed subsequently synthesized using typical nucleophilic substitution polycondensation reaction. A novel AB and ABA (or BAB) block copolymers were synthesized using sBCPSBP (sulfonated 4,4'-bis[4-chlorophenyl)sulfonyl]-1,1'-biphenyl), DHN (1,5-dihydroxynaphthalene), DFBP (decafluorobiphenyl) and HFIP (4,4'-hexafluoroisopropylidenediphenol). All block copolymers were easily cast and made into clear films. The structure and synthesized copolymers and corresponding membranes were analyzed using GPC (gel permeation chromatography), $^1H$-NMR ($^1H$ nuclear magnetic resonance) and FT-IR (Fourier transform infrared). TGA (Thermogravimetric analysis) and DSC (differential scanning calorimetry) analysis showed that the prepared membranes were thermally stable, so that elevated temperature fuel cell operation would be possible. Hydrophobic/hydrophilic phase separation and clear ionic aggregate block morpology was confirmed in both triblock and diblock copolymer in AFM (atomic force microscopy), which may be highly related to their proton transport ability. A sulfonated BAB triblock copolymer membrane with an ion-exchange capacity (IEC) of 0.6 meq/g has a maximum ion conductivity of 40.3 mS/cm at $90^{\circ}C$ and 100% relative humidity.