• Journal of Adhesion and Interface
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• v.20 no.2
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• pp.66-70
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• 2019

The surface of hydrophobic polypropylene (PP) fibers (spun-bonded fabric) was treated by an atmospheric plasma treatment method. These pre-treated hydrophilic PP fabrics were dip-coated in the aqueous poly(N-vinyl pyrrolidone) (PVP) solution. PVP layers on the surface of PP fiber were crosslinked by an irradiation of electron beam. The thickness of PVP hydrogels coated on the surface was easily controlled by changing the concentration of PVP in coating solution. The stepwise surface treatment, PVP coating, and hydrogel formation via electron beam irradiation were analyzed by the measurement of contact angle, scanning electron microscopy, and optical microscopy.

• Journal of the Korean Vacuum Society
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• v.13 no.3
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• pp.99-102
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• 2004

In this work the electrical characteristics of organic thin film transistors with the surface-treated organic gate insulator have been studied. For the surface treatment of gate dielectric, Ar plasma was used. Pentacene and PVP were used as active and dielectric layers respectively. Pentacene was thermally evaporated in vacuum at a pressure of about $10^{-6}$ Torr and at a deposition rate of 0.5 $\AA$/sec. PVP was spin coated and cured at $100^{\circ}C$. before pentacene deposition. organic thin film transistors with surface-treated gate insulators have provided improved operation characteristics.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.55-55
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• 2011

실리카 지지체 위에 은 (silver) 나노 입자를 부착시키는 방법으로는 지지체 표면을 먼저 은입자와 친화성이 큰 amino(-NH2), mercapto(-SH), cyan(-CN) 등의 관능기로 표면처리 하는 방법이 일반적으로 사용된다. 구체적으로 설명하면 첫 단계로 지지체인 실리카입자의 표면을 아민으로 표면 처리 한다. 실리카 입자위에 부착된 아민관능기는 입자 생성의 단계에서 은 (silver) 나노 입자가 붙는 접촉점의 역할과 핵 생성 장소로서의 역할을 하게되고, 아민 관능기의 이런 역할로 실리카 입자 표면에 부착된 핵이 생장하여 입자가 됨으로써 최종적으로 은(silver) 나노 입자가 실리카 지지체위에 부착된 형태의 나노복합체가 형성된다. 분자량이 다른 PVP를 사용하여 제조한, NH2와 SH로 계면처리 된 은-실리카 나노복합체제조를 시도하였다. 사용되는 PVP의 분자량이 증가함에 따라 긴 고분자 사슬에 의하여 생성된 입체장애가 증가하게 되어, 은 핵의 성장에 대한 물리적 장벽이 증가하게 된다. 그러므로 고정화된 은 입자의 크기가 감소하게 된다. 이러한 형상은 NH2기 또는 SH기로 계면 처리된 실리카를 이용하여 제조된 은-실리카 나노복합체 입자들에서 모두 관찰되지만, SH기로 계면처리된 실리카를 사용할 경우 고정화된 은 입자의 수가 더욱 많고, 크기 역시 더욱 균일함을 알 수 있다.

• Polymer(Korea)
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• v.36 no.3
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• pp.302-308
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• 2012

The objective of this study is to investigate optimum reaction conditions for the grafting of poly($N$-vinyl- 2-pyrrolidone) (PVP) onto the surface of plasma-treated polypropylene film. The plasma treatment conditions were fixed as 200 W rf power, 6 LPM Ar flow rate, 30 sec treatment time, and 5 min exposure time after treatment. For graft copolymerization, we investigated the change of grafting degree with respect to reaction time, reaction temperature and $N$-vinyl-2-pyrrolidone concentration. Maximum grafting degree was obtained at the conditions of 6 h reaction time, $90^{\circ}C$ reaction temperature, and 40% $N$-vinyl-2-pyrrolidone concentration. The introduction of PVP was confirmed by ATR-FTIR, XPS, and SEM analysis.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.7-11
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• 2011

In this paper, we proposed a simple and high-yield printing process for source and drain electrodes of organic thin film transistor (OTFT). The surface energy of PVP (poly 4-vinylphenol) gate dielectric was decreased from 56 $mJ/m^2$ to 45 $mJ/m^2$ by adding fluoride of 3000ppm into it. Meanwhile the surface energy of source and drain (S/D) electrodes area on the PVP was increased to 87 $mJ/m^2$ by treating the areas, which was patterned by photolithography, with oxygen plasma, maximizing the surface energy difference from the other areas. A conductive polymer, G-PEDOT:PSS, was deposited on the S/D electrode areas by brushing painting process. With such a simple process we could obtain a high yield of above 90 % in $16{\times}16$ arrays of OTFTs. The performance of OTFTs with the fluoride-added PVP was similar to that of OTFTs with the ordinary PVP without fluoride, generating the mobility of 0.1 $cm^2/V.sec$, which was sufficient enough to drive electrophoretic display (EPD) sheet. The EPD panel employing the OTFT-backpane successfully demonstrated to display some patterns on it.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.624-632
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• 2008

In this research, we developed new PDMS-glass based microbiochip consisted of the micromixer and microreactor for DNA ligation. The micromixer was composed of a straight channel integrated with nozzles and pillars, and the microreactor was composed of a serpentine channel. We coated the PDMS chip surface with the 0.25wt.% PVP solution to prevent the bubble generation which was caused by the hydrophobicity of the PDMS. The new micomixer was passive type and the mixing was enhanced by a convective diffusion using the nozzle and pillar. The 10.33mm long micromixer showed the good mixing efficiency of 87.7% at 500 l/min flow rate. We could perform the DNA ligation successfully in the microbiochip, and the ligation time was shortened from 4 hours in conventional laboratory method to 5 min in the microbiochip.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.145-145
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• 2013

저가 공정으로 진행되는 전기 방사 기법을 이용하여 태양전지용 구리 섬유를 제작하였다. 전기 방사 용액은 PVP, 에탄올, 염화 구리의 혼합액을 사용하였고, 금속염의 농도와 인가전압 변화에 따라 다양한 직경의 섬유가 제작되었다. 또한, 무질서 하게 방사되는 섬유의 배열 제어를 위해 컬렉터 형상을 변화하였다. 컬렉터에 형성된 고분자-구리 복합섬유를 채취한 후 열처리와 환원 처리를 통하여 구리 섬유를 얻었다. 환원된 금속 섬유는 scanning electron scope(SEM)을 통해 형상을 관찰하였으며, 4단자법으로 섬유의 전기적 특성에 관하여 알아보았다.

• Analytical Science and Technology
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• v.30 no.6
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• pp.312-318
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• 2017

The shelf life of 1,2-indandione/zinc (1,2-IND/Zn) solution and polyvinylpyrrolidone (PVP) solution, which are known as reagents for developing latent fingermarks deposited on the surface of thermal paper, was studied. The standard latent fingermarks used for comparisons were artificial latent fingermarks printed on thermally sensitive and non-sensitive surfaces with the same intensity. Upon treatment of standard latent fingermarks with the pre-mixed 1,2-IND/Zn and PVP solutions, the fingermarks could be successfully developed until 3 days after the preparation of the mixture. However, from the third day after mixing the reagents, blackening was observed on the surface of the thermal paper, indicating deterioration of the reagent performance. The 1,2-IND/Zn and PVP solutions separately stored without mixing in advance were mixed immediately before use, and the development efficiency of the latent fingermarks deposited on the surface of thermal paper was observed. The performance of the PVP solution decreased after 20 days from the preparation of the reagent. It was also found that the shelf life of 1,2-IND/Zn and PVP mixture was determined by the PVP solution. The effect of oxygen and moisture on the degradation of PVP was investigated. It was found that the performance of the PVP solution deteriorated because of the influence of moisture, though it was not affected by oxygen.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1546-1548
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• 2002

In this paper, the electrical characteristics of pentacene thin film transistors(TFTs) with stacked and surface-treated gate insulators have been investigated. The semiconductor layer of pentacene was thermally evaporated onto the stacked gate insulators. For the gate insulating materials. PVP(PolyvinylPhenol) and polystyrene were spin-coated with two different stacking orders, PVP-polystyrene and polystyrene-PVP. Rapid solvent evaporation during the spin-coating processes of these insulating layers produces non-equilibrium phase morphologies accompanied by surface undulations on gate insulator interfaces. This non-equilibrium phase morphology affects the growth mode of the subsequent pentacene layer. Therefore, in order to smoothen the gate dielectric surfaces, gate dielectric surfaces were rubbed laterally along the direction from the drain to the source TFTs with with stacked and surface-treated gate insulators have provided improved operational characteristics.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.477-478
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• 2006

In this paper, we could improve the mobility with OTS treatment on PVP gate, and also reduce the off-state current, which was usually large after OTS treatment, by using cosolvent. Also we treated Hexamethyl-disilazane (HMDS) and Ozone on PVP. It gives large off-state currents and on-currents.