• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4221-4226
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• 2011

Honeycomb-patterned polyvinypyrrolidone (PVP) thin films coated with nanometer-sized silver particles were prepared using honeycomb-patterned polystyrene (PS) template films fabricated by casting a polystyrene solution under humid condition. Silver was first metallized on the patterned PS films via silver nitrate ($AgNO_3$) reduction using tetrathiafulvalene (TTF) and a small amount of PVP as the reductant and dispersing agent, respectively. The effects of $AgNO_3$, TTF, and PVP solution concentrations during the reduction process in acetonitrile were determined to obtain a uniform silver-coated honeycomb-patterned PS film. Second, the silver-metallized patterned porous PS films were filled with high PVP concentration solutions via the spincoating process. Silver-coated patterned PVP films were obtained by peeling off the PVP layer from the template PS film after drying. The results show that the honeycomb-patterned PVP films uniformly coated with silver particles are conveniently obtained using the silver-coated patterned PS template, although the direct fabrication of these films using water droplets under humid conditions was not feasible because of the water solubility of PVP.

• Polymer(Korea)
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• v.29 no.3
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• pp.266-270
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• 2005

Iron oxide nanoparticles were prepared by the thermal decomposition of iron pentacarbonyl (Fe(CO)$_5$) Poly(vinylpyrrolidone) (PVP) was used as surface-modifying agent to control the size of the iron oxide nanoparticles. The crystalline structure of PVP coated iron oxide nanoparticles was determined by XRD. The size of PVP coated iron oxide nanoparticles was determined by TEM and ELS. The particle sizes of PVP coated iron oxide nanoparticles were controlled by adjusting the molar ratio of PVP/Fe (CO)$_5$, solvent and molecular weight of PVP Particle sizes increased with increasing PVP content. Spherical $50\~100$ nm sized iron oxide nanoclusters were produced when dimethylformamide was used as a solvent. And well-defined 10 nm iron oxide nanoparticles were produced in Carbitol. The prepared PVP coated iron oxide nanoparticles exhibited a well-dispersed property in water. The results obtained in this study confirmed the feasibility of the PVP-coated iron oxide nanoparticles as a biomaterial for MRI contrast agent.

• 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 Pharmaceutical Investigation
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• v.32 no.3
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• pp.173-179
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• 2002

Solid dispersions of ipriflavone with PVP were prepared by a spray-drying method in order to improve the bioavailability. They were measured with scanning electron microscopy, differential scanning calorimetry, x-ray powder diffraction, and Fourier transform infrared spectroscopy to evaluate the physicochemical interaction between ipriflavone and PVP and study the correlation between these physicochemical characteristics and bioavailability. Ipriflavone exhibited crystallinity, whereas PVP was almost amorphous. The area of the endotherm $({\Delta}H)$ of freezer milled ipriflavone, freezer milled ipriflavone physically mixed with freezer milled PVP, and physically mixed ipriflavone with PVP was almost the same, whereas ${\Delta}H$ of the solid dispersed ipriflavone with PVP was much smaller than that of the other preparation types. Also, the crystallinity and the crystal size of ipriflavone in the solid dispersed ipriflavone with PVP were much smaller than those of the other preparation types. From the in vivo test, the AUC of the solid dispersed ipriflavone with PVP was approximately 10 times higher than that of the physically mixed ipriflavone with PVP. The solid dispersion using the spray-drying method with a water-soluble polymer, PVP, may be effective for the improvement of the bioavailability.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.617-622
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• 2001

A protein-polysaccharide fraction of a Korean wild mushroom Psathyrella velutina, PVP, was prepared and its antitumor immunomodulatory activity was investigated. When PVP was administered once daily for seven days from day 1 to day 7 into male ICR mice implanted with 1 $\times$ 10$^{5}$ cells of sarcom 180 tumor cells into the peritoneum on day 4, it inhibited the growth of sarcoma 180 cells by 92.8%. In XTT assay, PVP also exhorted in vitro anti-proliferation activity on U-937, a human monoblastoid cell line, as well as sarcoma 180 cells. PVP showed marked stimulatory activity on the immune system in that it induced the accumulation of PEC (the stimulation index, Sl=4.90 at 100 mg/kg), stimulated the BALB/c mouse splenic lymphocytes to form lymphoblasts (Sl=5.75 at 100$\mu\textrm{g}$/ml), and upergulated the expression of CD25 molecules. All these results strongly support that PVP exhorts its antitumor activity through stimulation of the immune system as well as anti-proliferative activity on the tumor cells.

• Membrane Journal
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• v.28 no.2
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• pp.113-120
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• 2018

Global warming due to indiscriminate carbon dioxide emissions has a profound impact on human life by causing abnormal climate change and ecosystem destruction. As a way to reduce carbon dioxide emissions, in this study, we presented a polymeric membrane prepared by blending a self-crosslinkable P(GMA-g-PPG)-co-POEM (SP) copolymer and commercial polymer polyvinylpyrrolidone (PVP). As the content of PVP increased, it was observed that the gas permeance decreased and $CO_2/N_2$ selectivity increased. At 30 wt% PVP content, the $CO_2$ permeance of the membrane decreased from 72.9 GPU of pure SP polymer to 12.6 GPU, while $CO_2/N_2$ selectivity improved by 79% from 28.1 to 50.4. It results from the hydrogen bonding between the SP copolymer and PVP, leading to more compact structure of the polymer chains, which was confirmed by FT-IR, TGA, XRD and SEM analysis. Therefore, we suggest that the permeance and selectivity of the membranes can be easily adjusted as desired by controlling the PVP content in the SP/PVP polymer blend.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.374.1-374.1
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• 2016

Copper and zinc are well known elements with antibacterial effect. So in this research, Cu and Zn (CZ) nanofibers (NFs) were fabricated by electrospinning method using polyvinylpyrrolidone (PVP) for adjusting viscosity. The CZ/PVP precursor solutions were prepared with copper sulfate pentahydrate, and zinc acetate dihydrate. Distilled water was used for solvent and PVP was used to regulate the viscosity of precursor solution. The CZ/PVP NF composites were obtained by electrospinning method using the precursor solution. The average diameter of obtained CZ/PVP NFs was determined by optical microscopy using Motic image plus 2.0 program and was found to be 490 nm. The chemical environment of the obtained CZ/PVP NF composites was investigated with X-ray photoelectron spectroscopy (XPS). After heating the obtained CZ/PVP NF composites at 353 K, the solvent was removed. The characteristic C 1s, Cu 2p, and Zn 2p core level XPS peaks were observed. After calcination the CZ/PVP NF composites at 873 K in Ar environment for 5 hrs, PVP was decomposed at this temperature and CZ NF was obtained. This was confirmed by decreasing the intensity of C 1s.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.501-505
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• 2003

SrZrO$_3$ resistive oxides on Ag tapes were prepared by the sol-gel and dip coating method to investigate the effect of PVP content and drying condition on microstructure of the films. Although the film thickness increased with the addition of PVP, the amount of PVP and heat treatment were not effective to reduction of formation of microcracks at the films. However, lower drying temperature and longer drying time were beneficial to control the microcracks of the SrZrO$_3$ films, indicating that the microcracking of the films was governed primarily by the drying condition.

• Archives of Pharmacal Research
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• v.2 no.1
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• pp.49-64
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• 1979

In an atempt to elucidate further physicochemical properties of furosemide-PVP coprecipitates, extensive investigations such as TLC, UV,IR, NMR, X-ray diffraction, TGA and DTA studies were carried out for the furosemide test systems. X-ray diffraction studies revealed that the pure furosemide and the furosemide contained within a physical mixture were crystalline in nature. However, there was no crystallinity evident in the 1:5 furosemide-PVP 40,000 coprecipitate system, even after standing for two years. The various ratio furosemide-PVP 40,000 coprecipitate systems revealed that the coprecipitate containing a greater amount of PVP 40,000 than that of furosemide showed a crystalline state of furosemide and that the minimum amounts of PVP to make amorphous form of furosemide was 1:1 ratio of furosemide to PVP. From the furosemide-PVP coprecipitate systems with PVP of different molecular weights of 10,000, 40,000 and 360,000, all the 1:1 ratio coprecipitates did not exhibit any crystallinity of furosemide, whereas all the 2:1 ratio coprecipitates showed a presence of crystalline furosemide. All the coprecipitated preparations with PEG 4,000 and with PEG 6,000 showed the diffraction peaks indicating the presence of crystalline furosemide. The comparison of infrared spectra of the physical mixture and the coprecipitate showed an interaction such as association between the functional groups of furosemide and PVP in the molecular level, whereas the studies by TLC, UV and NMR showed its dissociation in methanol solution. The weight losses in TGA curves showed all the same patterns. However, a little different transition form in DTA thermograms was shown between the physical mixture and the coprecipitate, indicating the different thermal property.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.83-88
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• 2005

유기 절연층을 갖는 유기 박막트랜지스터 (organic TFT)를 제작하여 소자 성능을 조사하였다. 유기 절연층의 형성에서는 polyvinyl 계열의 PVP(poly-4-vinylphenol)와 PVT(polyvinyltoluene)를 용질로, PGMEA (propylene glycol mononethyl ether acetate)를 용매로 사용하였다. 또한, 열경화성 수지인 poly(melamine-co-formaldehyde)를 경화제로 사용하여 유기 절연층의 cross-link 를 시도하였다. MIM 구조로 유기 절연층의 특정을 측정한 결과, PVT는 PVP에 비해 절연 특성이 떨어지는 경향을 보였다. 게이트 절연막의 제작에서 PVP를 cobpolymer 방식과 cross-linked 방식으로 실험 해 본 결과, cross-link 방식에서 낮은 누설전류 특성을 나타내었다. OTFT 제작에서는 PVP를 용질로, poly(melanine-co-formaldehyde)를 경화제로 사용한 cross-linked PVP 를 게이트 절연막으로 이용하였다. PVP copolymer($20\;wt\%$)에 $10\;wt\%$ poly(melamine- co-formaldehyde)를 혼합한 cross-linked PVP 를 게이트 절연막으로 사용하여 top contact 구조의 OTFT를 제작한 결과 약 $0.23\;cm^2/Vs$의 정공 이동도와 약 $0.4{\times}10^4$의 평균 전류점멸비를 나타내었다.