• 전기화학회지
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• 제12권4호
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• pp.324-328
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• 2009

양극 (cathodes)과 음극 (anodes)이 서로 물리적으로 닿게되는 내부 단락 (internal short-circuit) 현상은 리튬이차전지 안전성 (safety) 이슈의 주요 원인으로 고려되고 있으며, 분리막 (separators)의 열 안정성 (thermal stability)에 의해 크게 영향을 받는 것으로 알려져 있다. 본 연구에서는 기존 폴리올레핀 (polyolefin) 계열 분리막에 비해 열 안정성이 현저히 개선된 세라믹 복합막 구조의 신규 분리막을 개발하여, 전지 내부 단락 발생을 억제하고자 하였다. 본 연구의 복합분리막은 알루미나 ($Al_2O_3$) 나노입자와 PVdF-HFP (polyvinylidene fluoride-hexafluoropropylene) 바인더로 구성된 세라믹 코팅층을, 폴리에틸렌 (polyethylene, PE) 분리막 양면에 도입시킴으로써 제조되었다. 세라믹 코팅층의 모폴로지는 코팅용액의 상전이 (phase inversion) 현상 제어를 통해 결정되었으며, 비용매 (물) 함량이 증가함에 따라 기공크기 및 기공구조가 보다 더 발달되었다. 이러한 세라믹 코팅층의 기공구조 변화는 복합분리막의 열 안정성 및 전기화학특성에 큰 영향을끼치는 것으로 관찰되었으며, 이를 상전이 현상 관점에서 체계적으로 해석하였다.

• 공업화학
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• 제28권6호
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• pp.691-695
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• 2017

본 연구에서는 알카라인 연료전지 환원극 가스확산층에 내열화학성이 우수한 초발수 성능을 부여하기 위하여 PDMS 코팅 공정을 최적화하였다. 성격이 상이한 두 개의 상용 가스확산층을 선택하였으며, 소재의 열적 안정성을 검토하여 코팅 온도를 최적화하고, PDMS 점도를 제어하여 코팅 균일성을 확보하고자 하였다. PDMS 전구체의 점도와 관계없이 $200^{\circ}C$ 부근에서 코팅하게 되면 모든 확산층 표면에서 높은 초발수 성능을 나타내었다. 가혹실험 조건에서 초발수 성능변화를 측정한 결과 1000 CS PDMS를 이용하여 28BC 가스확산층에 코팅한 경우가 가장 높은 내구성을 나타내었다.

• 대한치과보철학회지
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• 제45권6호
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• pp.795-804
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• 2007

Statement of problem. Nano-scale calcium-phosphate coating on the anodizing titanium surface using ion beam-assisted deposition (IBAD) has been recently introduced to improve the early osseointegration. However, not much is known about their surface characteristics that have influence on tissue-implant interaction. Purpose. This study was aimed to investigate microtopography, surface roughness, surface composition, and wettability of the titanium surface modified by the anodic oxidation and calcium phosphate coating using IBAD. Material and methods. Commercially pure titanium disks were used as substrates. The experiment was composed of four groups. Group MA surfaces represented machined surface. Group AN was anodized surface. Group CaP/AN was anodic oxidized and calcium phosphate coated surfaces. Group SLA surfaces were sandblasted and acid etched surfaces. The prepared titanium discs were examined as follows. The surface morphology of the discs was examined using SEM. The surface roughness was measured by a confocal laser scanning microscope. Phase components were analyzed using thin-film x-ray diffraction. Wettability analyses were performed by contact angle measurement with distilled water, formamide, bromonaphtalene and surface free energy calculation. Results. (1) The four groups showed specific microtopography respectively. Anodized and calcium phosphate coated specimens showed multiple micropores and tiny homogeneously distributed crystalline particles. (2) The order of surface roughness values were, from the lowest to the highest, machined group, anodized group, anodized and calcium phosphate deposited group, and sandblasted and acid etched group. (3) Anodized and calcium phosphate deposited group was found to have titanium and titanium anatase oxides and exhibited calcium phosphorous crystalline structures. (4) Surface wettability was increased in the order of calcium phosphate deposited group, machined group, anodized group, sandblasted and acid etched group. Conclusion. After ion beam-assisted deposition on anodized titanium, the microporous structure remained on the surface and many small calcium phosphorous crystals were formed on the porous surface. Nanoscale calcium phosphorous deposition induced roughness on the microporous surface but hydrophobicity was increased.

• 폴리머
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• 제37권1호
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• pp.22-27
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• 2013

본 연구에서는 기존의 이차전지용 폴리에틸렌(PE) 분리막에 poly(meta-phenylene isophthalamide) (Nomex)를 코팅함으로써 뛰어난 내열성을 가진 coated PE 분리막을 제조하였다. 다양한 Nomex 용액 조성과 PE 분리막 코팅 조건에 따라 제조한 분리막의 기계적 및 열적 특성을 열 노출 테스트와 TMA를 이용하여 측정하였고 제조된 코팅 분리막은 기존의 PE 분리막보다 향상된 열 수축률 및 기계적 성질을 보였다. 코팅 분리막의 전기화학적 성질은 이온전도도, 순환 전위-전류법, 충방전 사이클 테스트 등을 이용해 측정하였다.

• 멤브레인
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• 제23권2호
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• pp.136-143
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• 2013

최근 큰 각광을 받고 있는 표면개질소재 중 하나인 도파민은 알칼리 수용액상에서 자발적으로 반응이 진행되어 금속, 고분자 등 거의 모든 소재에 강하게 흡착되는 물질로 흡착 메커니즘 및 반응 후 최종구조에 관해 많은 논란이 있다. 기존의 도파민의 최종구조는 aryl-aryl 결합에 의한 고분자 구조가 제안되었지만, 본 연구에서는 구조분석을 통해 기존에 제안된 aryl-aryl 결합이 형성되지 않는 결과와 열적거동을 통해 고분자의 특징이 나타나지 않는 것을 확인하였으며, 기체투과거동을 통해 고분자와 같이 비다공성 코팅층을 형성하지 못하는 결과를 토대로, 도파민의 최종구조는 2차 결합에 의한 초분자 구조로 서로 응집되어 있는 것으로 판단된다.

• Korean Membrane Journal
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• 제1권1호
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• pp.86-92
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• 1999

The nanofiltration (NF) membranes based on poly(vinyl alcohol) (PVA) and sodium alginate (SA) were prespared. Homogeneous PVA/SA blend membranes were prepared by casting a PVA/SA (95/5 in wi%) mixture solution on an acryl plate followed by drying at a room temperature and by cros-slinking with glutaraldehyde (GA) for 20 minutes PVA/SA blend composite membranes were also prepared by coating a PVA/SA (95/5 in wi%) mixture solution on microporous polysulfone(PSF) supports. The PVA/SA active layer of the composite membrane was crosslinked at room temperature by using an membranes were characterized with a scanning electron microscopy (SEM) a fourier transform infrared spectroscopy (FTIR) and permeation tests. The permeation properties of the composite membrane were as follows: 1.3{{{{ {m }^{2 } }}}}/{{{{ {m }^{2 } }}}}day of flux and >95% of rejection at 200 psi for a 1000 ppm PEG600 solution.

• 한국막학회:학술대회논문집
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• 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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• pp.35-38
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• 1999

Nanofiltration (NF) composite membranes based of poly (vinyl alcohol) (PVA) and sodium alginate (SA) were prepared by coating PVA/SA (95/5 in wt %) mixture solutions on the microporous polysulfone (PS) supports, followed by the crosslinking with glutaraldehyed. The composite membranes prepared were characterized with a scanning electron microscopy (SEM), a fourier transform infrared spectroscopy(FTIR), an elecrtokinetic analyzer (EKA) and permeation tests.

• 한국표면공학회지
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• 제37권5호
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• pp.243-248
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• 2004

A palladium-nikel(Pd-Ni) alloy composite membrane has been fabricated on microporous nickel support formed with nickel powder. Plasma surface treatment process is introduced as pre-treatment process instead of HCI activation. Pd coating layer was prepared by dc magnetron sputtering deposition after $H_2$ plasma surface treatment. Palladium-nickel alloy composite layer had a fairly uniform and dense surface morphology. The membrane was characterized by permeation experiments with hydrogen and nitrogen gases at temperature of 773 K and pressure of 2.2psi. The hydrogen permeance was 6 ml/minㆍ$\textrm{cm}^2$ㆍatm and the selectivity was 120 for hydrogen/nitrogen($H_2$/$N_2$) mixing gases at 773 K.

• 청정기술
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• 제14권1호
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• pp.35-39
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• 2008

본 연구에서는 용매에 따른 고분자의 용해도 차이를 이용하여 슬라이드글라스 표면위에 초소수성 고분자막을 성공적으로 제조하였다. 폴리스타이렌 (PS)을 tetrahydrofuran (THF)에 녹인 후 다시 에탄올(EtOH)을 첨가하여 두 용매의 용해도 차이로 표면에 초소수성 성질을 갖게 제조하였다. 한편, EtOH 첨가, 코팅방법, 용액혼합 시간과 속도 및 다른 알콜들이 형성된 표면의 소수성에 미치는 영향들을 각각 조사하였다. 접촉 각 측정기를 사용하여 측정한 결과 $150^{\circ}$ 이상의 물 접촉각을 확인하였고, 광학현미경(optical microscopy)과 주사전자현미경(scanning electron microscope, SEM)으로 관찰한 표면 구조는 $5\;{\mu}m$ 이하의 입자들로 구성된 미세다공성 구조임이 확인되었다.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 제6회 하계 Workshop (98 한국막학회, 국립환경연구원 국제 Workshop, 수자원 보전과 막분리 공정)
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• pp.135-153
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• 1998

Nanofiltration (NF) is a recently introduced term in membrane separation. In 1988, Eriksson was one of the first authors using the word 'nanofiltration' explicitly. Some years before, FilmTech started to use this term for their NF50 membrane which was supposed to be a very loose reverse osmosis membrane or a very tight ultrafiltration membrane. Since then, this term has been introduced to indicate a specific boundary of membrane technology in between ultrafiltration and reverse osmosis. The application fields of the NF membranes are very broad as follows: Demeneralizing water, Cleaning up contaminated groundwater, Ultrapure water production, Treatment of effleunts containing heavy metals, Offshore oil platforms, Yeast production, Pulp and paper mills, Textile production, Electroless copper plating, Cheese whey production, Cyclodextrin production, Lactose production. The earliest NF membrane was made by Cadotte et al, using piperazine and trimesoyl chloride as monomers for the formation of polyamide active layer of the composite type membrane. They coated very thin interfacially potymerized polyamide on the surface of the microporous polysulfone supports. The NF membrane exhibited low rejections for monovalent anions (chloride) and high rejections for bivalent anions (sulphate). This membrane was called NS300. Some of the earliest NF membranes, like the NF40 membrane of FilmTech, the NTR7250 of Nitto-Denko and the UTC20 and UTC60 of Toray, are formed by a comparable synthesis route as the NS300 membrane. Commercially available NF membranes nowadays are as follows: ASP35 (Advanced Membrane Technology), MPF21; MPF32 (Kiryat Weizmann), UTC20; UTC60; UTC70; UTC90 (Toray), CTA-LP; TFCS (Fluid Systems), NF45; NF70 (FilmTec), BQ01; MX07; HG01; HG19; SX01; SX10 (Osmonics), 8040-LSY-PVDI (Hydranautics), NF CA30; NF PES 10 (Hoechst), WFN0505 (Stork Friesland). The typical ones among the commercially available NF membranes are polyamide composite membrane consisting of interfacially polymerized polyamide active layer and microporous support. While showing high water fluxes and high rejections of multivalent ions and small organic molecules, these membranes have relatively low chemical stability. These membranes have low chlorine tolerance and are unstable in acid or base solution. This chemical instability is appearing to be a big obstacle for their applications. To improve the chemical stability, we have tried, in this study, to prepare chemically stable NF membranes from PVA. The ionomers and interfacially polymerized polyamide were used for the modification of'the PVA membranes. For the detail study of the active layer, homogeneous NF membranes made only from active layer materials were prepared and for the high performance, composite type NF membranes were prepared by coating the active layer materials on microporous polysulfone supports.