• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.258-258
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• 2006

Electrospun fibers of poly(vinyl alcohol) (PVA) were successfully prepared and applied as drug carriers for transdermal drug delivery system. Sodium Salicylate (SS) was the model drug and it was incorporated in the PVA fibers by adding 20 % of SS in a PVA solution prior to electrospinning. Electrospinning of SS-containing PVA solution resulted in the formation of beaded fibers. In order to control the rate of SS release and decrease water solubility of PVA, the SS-loaded electrospun PVA mat was cross-linked by either glutaraldehyde or glyoxal vapor. The morphology, thermal behavior, swelling behavior, release characteristic, kinetics of drug release and also toxicity of the cross-linked sample were investigated.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.388.1-388.1
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• 2014

The performance of PVA(polyvinyl alchol) is better than another organic dielectric material. Therefore, PVA has been researched for organic and in-organic dielectric material. But research of changing PVA's dielectric constant and leakage current by increasing temperature and concentration was insigificant. We try to find pure PVA and cross-linked PVA's characteristic of dielectric by changing temperature and concentration. 5/10/15wt% PVA concentration (5% interval) was in progress, PVA at $100/150/200/250^{\circ}C$ ($50^{\circ}C$ interval) of experiments was conducted in relation to temperature. The higher the concentration, leakage currents decrease, and dielectric constant is increased. With regard to temperature, we could not see a big change of leakage current and dielectric constant of pure PVA until $200^{\circ}C$. However, we could see a tendency to increase significantly at $250^{\circ}C$. Also, leakage current and dielectric constant of cross-linked PVA gradually increased from at $100^{\circ}C$ to $200^{\circ}C$ and then sharply increased from at $250^{\circ}C$. We tried to find that PVA's inner bonds(hydroxyl group (OH-) lead to the results.

• 반도체디스플레이기술학회지
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• 제9권4호
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• pp.1-5
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• 2010

The PVA (poly-vinyl alcohol) insulators were spun coated onto ITO coated glass substrates with the capacitors of Glass/ITO/PVA/Al structure. The effects of PVA concentrations (3.0, 4.0 and 5.0 wt%) on the morphology and electrical properties of the films were investigated. As the concentration of PVA increased from 3.0 to 5.0 wt%, the leakage current of device decreased from 17.1 to 0.23 pA. From the AFM measurement, the RMS value decreased with increasing PVA concentration, showing the improvement of insulator film roughness. The capacitances of the films with PVA concentrations of 4.0 and 5.0 wt% were about 28.1 and 24.2 nF, respectively. The lowest leakage current of 1.77 PA was obtained at the film thickness of 117.5 nm for the device with fixed PVA concentration of 5.0 wt%.

• Macromolecular Research
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• 제16권3호
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• pp.189-193
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• 2008

Thermal cross-linking method of poly(vinyl alcohol) (PVA) using poly(acrylic acid) (PAA) was carried out on PVA/PAA hydrogels. The level of gelation was measured in the PVA/PAA hydrogels with various PAA contents. The swelling behavior at various pHs showed that the swelling kinetics and water contents of the PVA/PAA hydrogels reached equilibrium after 30 h, and the time to reach the equilibrium state decreased with increasing PAA content in the hydrogel. The water content increased with increasing pH of the buffer solution. The permeation and release of the drug were tested using indomethacin as a model drug. The permeated and released amounts of the drug increased with decreasing the PAA content because of the low free volume in the hydrogel due to the higher cross-linking density. The kinetic profile of drug release at various pHs showed that all samples reached the equilibrium state within the 5 h.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.445-448
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• 2006

Bias stress effect in pentacene organic thin-flim transistors with cross-linked PVA gate dielectric is analyzed. For negative gate bias stress, positive threshold voltage shift is observed. The injected charges from the gate electrode to the defect states of gate dielectric are regarded as the main origin of $V_T$ shift. The reduced bias stress effect using $SiO_2$ blocking layer confirms the assumed mechanism. It is also demonstrated that the inverter with $SiO_2$ blocking layer shows the negligible hysteresis owing to the reduced bias stress effect.

• 센서학회지
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• 제1권2호
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• pp.125-130
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• 1992

습도감지물질로서 PMMA박막을 사용하여 저항형 습도감지소자를 제조하고 그 특성을 조사하였다. PMMA에 DVB를 첨가하여 가교결합을 일으키고 여기에 PVA를 섞어 제조된 습도센서는 상대습도의 증가에 따라 저항의 변화를 나타내었으며, 흡착에 비해 탈착 시 약 3% 미만의 히스테리시스 특성을 나타내었다. 또한 제조된 소자는 좋은 장기안정도를 보였으며, 응답시간은 흡착시에는 약 7분, 탈착시에는 약 5분이었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.110-111
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• 2019

Concrete with high thixotropy has a lower plastic viscosity when pour in, thus demonstrating fluidity, and After poured, the viscosity can be restored again to ensure stable progress without additional liquidity and material separation. Therefore, in this study, a basic study of thixotropy of concrete was proceeded through cross-linked bond of PVA and Borax. Therefore, it is judgment that the higher the concentration of boron solutions, the higher the strength of the interconnections between PVA and boron.

• Journal of Information Display
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• 제6권2호
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• pp.16-18
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• 2005

Hybrid insulator pentacene thin film transistors (TFTs) are fabricated with thermally grown oxide and cross-linked polyvinylalcohol (PVA) including surface treatment by dilute ploymethylmethacrylate (PMMA) layer on $n^+$ doped silicon wafer. Through the optimization of $SiO_2$ layer thickness in hybrid insulator structure, carrier mobility is increased to more than 35 times than that of the TFT which has only a gate insulator of $SiO_2$ at the same electric field. The carrier mobility of $1.80cm^2$/V-s, subthreshold swing of 1.81 V/decade, and $I_{on}/I_{off}$ current ratio> $1.10{\times}10^5$ are obtained less than -30 V bias condition. The result is one of the best reported performances of pentacene TFTs with hybrid insulator including cross-linked PVA layer as a gate insulator at relatively low voltage operation.

• 멤브레인
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• 제10권3호
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• pp.148-154
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• 2000

본 연구에서는 sulfur-succinic acid의 가교제를 이용한 가교된 폴리비닐알코올(poly(vinyl alcohol), PVA) 가교막을 이용하여 MTBE-methanol 혼합액에 대하여 조업온도, 가교제의 조성에 따른 증기투과 공정의 투과 특성을 조사 하였다. 팽윤 실험을 통해 PVA/SSA 가교막에 대하여 가교제 조성에 따른 막의 구조와 PVA의 하이드록실기(-OH), SSA의 설폰기(-$SO_3$H)와 용매와의 수소결합의 두 가지 인자가 상호 보완적으로 작용하고 있음을 알 수 있었다. 투과 특성에 있어 SSA의 설폰기가 중요한 인자로 작용하였다. 예를 들면 7% SSA 막에 대해서는 수소결합의 효과보다는 가교도의 효과가 투과 특성에 중요한 요인으로 작용하며 5% SSA에 대해서는 수소결합의 효과가 중요하게 작용하였다. 증기투과 공정에 있어 막과 직접 접촉하는 증기상이 액상에 비하여 methanol의 농도가 낮아 PVA의 하이드록실기와 methanol과의 수소결합 확률이 감소함에 따라 투과 특성에 영향을 미친다. 결과적으로 7% SSA 막에 대하여 MTBE/mthanol=80/20 혼합액에 대하여 공급액의 온도 3$0^{\circ}C$에서 선택도 2187, 투과도 4.84g/$m^2$hr를 보여 주었다.

• 멤브레인
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• 제28권4호
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• pp.279-285
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• 2018

이소프로필알코올/물 혼합물은 가교된 폴리비닐알코올 복합막을 이용하여 투과특성평을 알아보았다. 검화도가 다른 3종 PVA를 이용하여 고분자의 농도와 GA 농도에 따라서 투과특성을 확인하였다. 복합막은 PVA 용액을 PAN 지지체 위에 캐스팅한 후, 열가교를 통해 제조하였다. PVA 농도가 증가할수록 투과도는 감소하지만 선택도는 증가하는 것을 확인하였다. PVA-3이 7 wt% 농도로 코팅된 복합막에서 $209g/m^2h$의 투과도를 가지고, 100 이상의 선택도를 가지는 것을 확인하였다. 침지형 분리막을 제조하여 feed tank 온도와 feed 용액의 IPA 농도에 따라서 투과실험을 확인하였다. 또한 IPA 수용액에 농축실험을 지속적으로 한 결과, 60시간 후에 IPA의 농도가 99%까지 증가하는 것을 확인하였다.