• Title/Summary/Keyword: PVP

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In Vitro Release of Acetaminophen from Mucoadhesive Microsphere Prepared by Poly(acrylic acid)/poly(vinyl pyrrolidone) Interpolymer Complex

  • Chun, Myung-Kwan;Cho, Chong-Su;Choi, Hoo-Kyun
    • Proceedings of the PSK Conference
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    • pp.231.1-231
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    • 2003
  • Mucoadhesive microsphere was prepared by interpo]ymer complexation of po]y(acrylic acid) (PAA) with po]y(vinyl pyrrolidone) (PVP) using solvent diffusion method. The loading efficiency of acetaminophen into the microsphere was 91.3 ${\pm}$ 6.5%. The release rate of acetaminophen from the PAA/PVP complex microspheres was slower than that from PVP microspheres at pH 2.0 and 6.8. The dissolution of microspheres made of the complex was significantly slower than those made of PVP due to H-bond between PVP and PAA. As a result, the release rate of acetaminophen from the complex microspheres was slower than that from PVP microspheres.

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Organic Thin Film Transistors with Cross-linked PVP Gate Dielectrics by Using Photo-initiator and PMF

  • Yun, Ho-Jin;Baek, Kyu-Ha;Park, Kun-Sik;Shin, Hong-Sik;Ham, Yong-Hyun;Lee, Ga-Won;Lee, Ki-Jun;Wang, Jin-Suk;Do, Lee-Mi
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.312-314
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    • 2009
  • We have fabricated pentacene based organic thin film transistors (OTFTs) with formulated poly[4-vinylphenol] (PVP) gate dielectrics. The gate dielectrics is composed of PVP, poly[melamine-coformaldehyde] (PMF) and photo-initiator [1-phenyl-2-hydroxy-2-methylpropane-1-one, Darocur1173]. By adding small amount (1 %) of photo-initiator, the cross-linking temperature is lowered to $115^{\circ}C$, which is lower than general thermal curing reaction temperature of cross-linked PVP (> $180^{\circ}C$). The hysteresis and the leakage current of the OTFTs are also decreased by adding the PMF and the photoinitiator in PVP gate dielectrics.

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Characteristics of Carbon Nano Fluid Added PVP (PVP가 첨가된 탄소나노유체의 특성에 대한 연구)

  • Seo, Hyang-Min;Park, Sung-Seek;Kim, Nam-Jin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.5
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    • pp.289-295
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    • 2010
  • In this study, the enhancement of the thermal conductivity of water in the presence of multi-walled carbon nanotubes, MWCNT, was investigated. Sodium Dodecyl Sulfate, SDS, and Polyvinylpyrrolidone, PVP, were employed as the dispersant. SDS or PVP was added in pure water. And then, MWCNT of 0.0005, 0.001, 0.002, 0.003, 0.004, 0.005, 0.01, and 0.02 vol% was dispersed respectively. The thermal conductivity and the viscosity were measured with a transient hot-wire instrument built for this study and the DV II+ Pro viscometer. The results showed that PVP had good thermal conductivity at 300 wt% and this was better than that of SDS 100 wt%, also, the viscosity of nano fluid added PVP rapidly increased until 0.02 vol%.

Disssolution Characteristics of Phenobarbital and Phenobarbital-PVP Coprecipitate (Phenobarbital 및 Phenobarbital-PVP 공침물(共沈物)의 용출(溶出)에 관한 연구(硏究))

  • Shin, Sang-Chul;Lee, Min-Hwa;Kim, Shin-Keun
    • Journal of Pharmaceutical Investigation
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    • v.8 no.2
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    • pp.11-17
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    • 1978
  • Phenobarbital의 용출속도(溶出速度)를 증가시키기 위하여 PVP와의 공침물(共沈物)을 형성(形成)한 후 일정(一定)한 표면적(表面積)하에서의 용출속도(溶出速度)를 비교검토(比較檢討)하였다. $37^{\circ}C$, 150r.p.m${\times}$에서의 rate constannt of dissolution, k,는 phenobarbital이 $8.75{\times}10^{-6}M/min$, 1 : 2 phenobarbital-PVP coprecipiate는 $5.35{\times}10^{-5}M/min$이었으며, activation energy of dissolution, Ea는 phenobarbital이 약 10,600cal/mole coprecipitate는 약 5,800cal/mol이었다. 그리고 X-ray diffraction study에 의(依)하면 페노바르비탈 단일물질(單一物質)이나, PVP와의 physical mixture에서는 페노바르비탈의 결정피크를 나타내었으나, PVP와의 공침물(共沈物)의 경우(境遇)에는 페노바르비탈의 결정피크를 인지(認知)할 수 없었다.

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Electrical Characteristics of Cu2O-PVP Nanofibers Fabricated by Electrospinning (전기방사법으로 제조된 Cu2O-PVP 나노사의 전기적 특성)

  • Kwak, Ki-Yeol;Cho, Kyoung-Ah;Yun, Jungg-Won;Kim, Sang-Sig
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.8
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    • pp.650-653
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    • 2009
  • Hybrid nanofibers made of $Cu_2O$ and polyvinyl pyrrolidone were fabricated by electrospinning on glass substrates. The current magnitude of the $Cu_2O$-PVP hybrid nanofibers is 10 times larger than that of pure PVP nanofibers. In addition, $Cu_2O$-PVP nanofibers possess high sensitivity to air at room temperature than pure PVP nanifibers.

The thickness effect on surface and electrical properties of PVP layer as insulator layer of OTFTs (OTFT 소자의 절연층으로써 두께에 따른 PVP 층의 표면 및 전기적 특성)

  • Seo, Choong-Seok;Park, Yong-Seob;Park, Jae-Wook;Kim, Hyung-Jin;Yun, Deok-Yong;Hong, Byung-You
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.245-245
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    • 2008
  • In this work, we describe the characterization of PVP films synthesized by spin-coater method and fabricate OTFTs of a bottom gate structure using pentacene as the active layer and polyvinylphenol (PVP) as the gate dielectric on Au gate electrode. We investigated the surface and electrical properties of PVP layer using an AFM method and MIM structure, and estimated the device properties of OTFTs including $I_D-V_D$, $I_D-V_G$, threshold voltage $V_T$, on/off ratio, and field effect mobility.

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Verification of Bonding Force between PVP Dielectric Layer and PDMS for Application of Flexible Capacitive-type Touch Sensor with Large Dynamic Range (넓은 다이내믹 레인지의 유연 촉각센서 적용을 위한 PVP 유전층과 PDMS 접착력 검증)

  • Won, Dong-Joon;Huh, Myoung;Kim, Joonwon
    • The Journal of Korea Robotics Society
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    • v.11 no.3
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    • pp.140-145
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    • 2016
  • In this paper, we fabricate arrayed-type flexible capacitive touch sensor using liquid metal (LM) droplets (4 mm spatial resolution). Poly-4-vinylphenol (PVP) layer is used as a dielectric layer on the electrode patterned Polyethylene naphthalate (PEN) film. Bonding tests between hydroxyl group (-OH) on the PVP film and polydimethylsiloxane (PDMS) are conducted in a various $O_2$ plasma treatment conditions. Through the tests, we can confirm that non-$O_2$ plasma treated PVP layer and $O_2$ plasma treated PDMS can make a chemical bond. To measure dynamic range of the device, one-cell experiments are conducted and we confirmed that the fabricated device has a large dynamic range (~60 pF).

Electrical Properties of PVP Gate Insulation Film on Polyethersulfone(PES) and Glass Substrates (Polyethersulfone(PES) 및 유리 기판위에 제작된 PVP 게이트 절연막의 전기적 특성)

  • Shin, Ik-Sup;Gong, Su-Cheol;Lim, Hun-Seoung;Park, Hyung-Ho;Chang, Ho-Jung
    • Journal of the Microelectronics and Packaging Society
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    • v.14 no.1
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    • pp.27-31
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    • 2007
  • The cpapcitors with MIM(metal-insulator-metal) structures using PVP gate insulation films were prepared for the application of flexible organic thin film transistors (OTFT). The co-polymer organic insulation films were synthesized by using PVP(poly-4-vinylphenol) as a solute and PGMEA(propylene glycol monomethyl ether acetate) as a solvent. The cross-linked PVP insulation films were also prepared by addition of poly(melamine-co-formaldehyde) as thermal hardener. The leakage current of the cross- linked PVP films was found to be about 1.3 nA on Al/PES(polyethersulfone) substrate, whereas, on ITO/ glass substrate was about 27.5 nA indicating improvement of the leakage current at Al/PES substrates. Also, the capacitances of all prepared samples on ITO/glass and Al/PES substrates w ere ranged from 1.0 to $1.2nF/cm^2$, showing very similar result with the calculated capacitance values.

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Humidity Sensor using Polyvinylpyrrolidone-Coated Mach-Zehnder Interferometer in Planar Lightwave Circuit (폴리비닐피롤리돈이 코팅된 마하젠더 간섭계 기반의 평판형 광도파로 습도센서)

  • Kim, Ju Ha;Kim, Myoung Jin;Jung, Eun Joo;Hwang, Sung Hwan;Lee, Woo Jin;Choi, Eun Seo;Rho, Byung Sup
    • Korean Journal of Optics and Photonics
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    • v.24 no.5
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    • pp.251-255
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    • 2013
  • In this paper, the characteristics of a humidity sensor implemented by Mach Zehnder Interferometer (MZI) in a Planar Lightwave Circuit (PLC) have been designed and demonstrated. The humidity outside is detected with polyvinylpyrrolidone (PVP) coated on the etched arm of the MZI. The length of the etched arm is 10 mm and the PVP was coated by dip-coating into the etched region. As the refractive index of the PVP changes with the surrounding humidity, the PVP-coated humidity sensor presented changes in the interferogram depending on RH (Relative Humidity) around the PLC. The measured results show that the proposed humidity sensor works successfully in the range of 30% to 80% of RH.

Light Scattering Effect of Incorporated PVP/Ag Nanoparticles on the Performance of Small-Molecule Organic Solar Cells

  • Heo, Il-Su;Park, Da-Som;Im, Sang-Gyu
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.221-221
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    • 2012
  • Small-molecule organic photovoltaic cells have recently attracted growing attention due to their potential for the low-cost fabrication of flexible and lightweight solar modules. The PVP/Ag nanoparticles were synthesized by the reaction of poly vinylpyrrolidone (PVP) and silver nitrate at $150^{\circ}C$. In the reaction, the size of the nanoparticles was controlled by relative mole fractions between PVP and Ag. The PVP/Ag nanoparticles with various sizes were then spin coated on the patterned ITO glass prior to the deposition of the PEDOT:PSS hole transport layer. The scattering of the incident light caused by these incorporated nanoparticles resulted in an increase in the path length of the light through the active layer and hence the enhancement of the light absorption. This scattering effect increased as the size of the nanoparticles increased, but it was offset by the decrease in total transmittance caused by the non-transparent nanoparticles. As a result, the maximum power conversion efficiency, 0.96% which was the value enhanced by 14% compared to the cell without incorporation of nanoparticles, was obtained when the mole fraction of PVP:Ag was 24:1 and the size of the nanoparticles was 20~40 nm.

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