• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.187-190
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• 2005

Silk fibroin (SF) films were prepared using various plasticizers and their physical properties were determined. Polyethylene glycol (PEG)-SF and polypropylene glycol (PPG)-SF films had tensile strengths (TS) of 23.71 MPa and 24.51 MPa, respectively, whereas the glycerol (G)-SF film had the lowest TS of 14.24 MPa. G-SF film had the highest $\%$ elongation, compared to PPG-SF and PEG-SF films. Water vapor permeability (WVP) of SF films varied with addition of plasticizers, and PEG-SF film had the lowest WVP. There was no significant difference in Hunter L value among treatments, but PEG-SF film had higher Hunter a and b values. These results suggest that SF film could be applied to food packaging and that the addition of plasticizers should improve the physical properties of SF film.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.312-316
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• 2013

Caffeine is a thermogenic agent that can be used in weight loss products. In order to achieve a sustained release of caffeine, silk fibroin (SF) film was uses as carrier. It has been shown that the loading method of caffeine into SF film affected the uniform distribution of caffeine in the SF film. When caffeine was added directly into SF solution, gelation has been occurred immediately and prevented the uniform distribution of caffeine. On the other hand, caffeine was dissolved in methanol in order to load the caffeine in SF film and crystallize the SF film at the same time. However, due to the fast evaporation of methanol, caffeine was recrystallized on the surface of SF film rather than penetrating into the film. Finally, caffeine was loaded into pre-crystallized SF film and uniform distribution of caffeine could be achieved. There was an initial burst of caffeine during the first 15 min, but after that a sustained release was achieved.

• Analytical Science and Technology
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• v.27 no.1
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• pp.27-33
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• 2014

This study described about preparation of the cross-linked silk fibroin (SF) film by ${\gamma}$-irradiation of the casted SF film, which is fabricated from aqueous solution regenerated via fibers of cocoons and their application as supports for human cell culture. The properties of cross-linked SF film were evaluated by FT-IR spectroscopy, contact angle, solubility to water, thermal analysis, surface area analyzer, and morphology via scanning electron microscopy (SEM). The cross-linked SF films were not dissolved in water and exhibited the rough surface morphology, large surface area, and good thermal properties. The human fibroblast cell (CCD-986sk) and embryo kidney-ft cell were well growed on the surface of cross-linked SF film supports prepared by ${\gamma}$-irradiation. The cross-linked SF film prepared by ${\gamma}$-irradiation can be used as biomaterials for human cell culture.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1203-1206
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• 2008

Silk fibroin (SF) film containing catechin was prepared and the antimicrobial activity as well as physical property of the film was examined. Tensile strength of the SF film decreased with increasing concentration of catechin, and water vapor permeability of the film decreased. The film's antimicrobial activity against Escherichia coli O157:H7 increased with increasing catechin concentration. Sausage samples were inoculated with E. coli 0157:H7 and Listeria monocytogenes, and the sausage packaged with the SF film containing catechin had a decrease in the populations of E. coli O157:H7 and L. monocytogenes by 0.83 and 0.85 log CFU/g after 12 days of storage, respectively, compared to the control. In addition, the sausage had a better quality than the control regarding lipid oxidation. Our results indicate that sausages can be packed with the SF film containing catechin to extend shelf life.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2120-2122
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• 1999

$SF_6$ gas has been widely used the gas insulated transmission line, gas insulated transformer and gas insulated substation and Polyester film used as the turn insulation with other material. $SF_6$ gas has been actively studied in domestic and foreign countries. In general, when dielectric surface electric field exceed any electric field strength on air, corona discharge is occurred from the dielectric surface. This paper presents the insulation strength of turn insulation of $SF_6$-PET film studied under application of AC voltage, constitute of the plane to plane with PET Film. The results obtained in experimental are summarized that Partial Discharge Initial Voltage(PDIV) of turn insulation depend on gas pressure, but Breakdown Voltage(BDV) did not depend on gas pressure.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.163-170
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• 2002

In this paper, silk fibroin (SF)/polyurethane (PU) blend films were fabricated to develop a new biomaterial for biomedical applications. These blend films were prepared using formic acid as a cosolvent, and structural characteristics and properties of blend films were investigated. FTIR results suggested that there was no specific interaction between SF and PU, implying molecular immiscibility in SF/PU blend films. Furthermore, it was revealed by XRD method that the crystalline region of blend components was not perturbed by counterpart polymers. The degree of phase separation of SF/PU blend films was diminished by increasing PU content in blend. Especially, the blend with 70% content of PU showed no evidence of macro-phase separation in SEM observation. However, SF/PU blend (70/30) was revealed to be phase-separated in a lower dimension confirmed by DMTA measurement. TGA result showed that thermal decomposition temperature of blend film was slightly decreased compared to those of SF and PU polymer itself, Though mechanical properties of SF/PU blend films were not good enough due to the solvent, blood compatibility of PU can be enhanced markedly by mixing with SF for SF/PU blend film.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.264-264
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• 2011

Poly [(N, N'-oxydiphenylene) pyromellitimide], polyimide (PI) film은 기계적 강도가 매우 우수하고 열적, 화학적 안정성이 뛰어난 재료로서 전자제품의 소형화, 경령화, 고성능화를 위한 차세대 flexible electronic device에 적용하기 위하여 많은 연구가 진행되고 있다. 그러나 PI의 특성상, 매우 낮은 표면에너지로 인해 금속과의 접촉력이 좋지 않은 단점을 가지고 있다. 본 연구에서는, 금속박막과 PI film 과의 접촉력을 증가시키기 위해 remote-type modified dielectric barrier discharge (DBD) module을 이용하여 대기압 플라즈마 표면처리를 하였다. 실험에 사용된 gas composition은 각각 $N_2$/ He/ $SF_6$, $N_2$/ He/ $O_2$, $N_2$/ He/ $SF_6$/ $O_2$, $N_2$/ He/ $SF_6$/ $O_2$ 이다. $N_2$/ He/ $SF_6$/ $O_2$ gas composition을 이용하여 PI 표면을 플라즈마 처리한 경우, C=O 결합이 PI film 위에 생성됨으로써, 접촉각이 매우 낮게 형성됨을 관찰할 수 있었다. 이와는 반대로 $N_2$/ He/ $SF_6$ gas composition 을 사용하였을 경우에는 C-Fx 화학적 결합이 생성되기 때문에 가장 높은 접촉각이 형성됨을 관찰할 수 있었다. 특히, $N_2$ (40 slm)/ He (1 slm)/ $SF_6$ (1.2 slm) gas composition에 $O_2$ gas를 0.2 slm부터 1.0 slm까지 변화시켜가며 PI film 표면을 처리한 결과, $O_2$ gas를 0.9 slm 첨가하였을 때, 가장 낮은 $9.3^{\circ}$의 접촉각을 얻을 수 있었다. 이는 0.9 slm의 $O_2$ gas를 첨가하였을 때, 가장 많은 양의 $O_2$ radical이 생성되기 때문에 많은 양의 C=O 결합이 생성되기 때문이다. 최적화된 $N_2$ (40 slm)/ He (1 slm)/ $SF_6$ (1.2 slm)/ $O_2$ (0.9 slm) gas composition 조건에서 Ag film과 PI film과의 접촉력을 관찰할 결과, 111 gf/mm를 얻을 수 있었다.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.63-67
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• 2001

Up to now, most studies about Pt-etching have been focused on physical sputtering mechanism with Cl-based plasma, while only a limited results are available for etching characteristics with fluorine-based plasma. In this study, etch characteristics of Pt thin film with $Cl_2$/Ar and $SF_{6}$/Ar Ar gas chemistries have been studied with ECR plasma etching system. It is confirmed that $SF_{6}$/Ar Ar plasma chemistry could make volatile etch-products through the reaction with Pt thin film. Also the improvement in etch rate, etch profile and surface roughness is obtained due to the formation of volatile platinum fluoride compounds.

• International Journal of Industrial Entomology and Biomaterials
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• v.30 no.2
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• pp.75-80
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• 2015

The wet spinning of silk solution has attracted researchers' attention because of 1) unique properties of silk as a biomedical material and 2) easy control of the structure and properties of the regenerated silk fiber. Recently, studies have reported that different silkworm varieties produce silk with differences in the molecular weight (MW) and other mechanical properties of the regenerated silk fibroin (SF) film. In this study, we look at the effect of different Bombyx mori varieties on the wet spinning of SF. Although five regenerated SFs from different silkworm varieties have different MWs and solution viscosity, the wet spinnability and post drawing performance of regenerated SFs were not different. This result is due to low variability in the MW of the regenerated SF samples from the different silkworm varieties. In addition, unlike regenerated SF films, the mechanical properties of wet spun regenerated SF filament were not affected by silkworm variety. This result suggests that the mechanical properties of wet spun SF filament are less affected by MW than those of SF film are.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.291-297
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• 1999

The plasma etching of tungsten thin films has been studied with $SF_6$ gas in RIE system. The etch rate of ${\alpha}$-phase W film with $SF_6$ gas plasma has been showed to depend strongly on process parameters ($SF_6$, $SF_6-N_2$ gas). Effect of $N_2$ addition and etching selectivity between W film and photoresist have also been studied in detail. Etching profiles between W film and photoresist were investigated by SEM. The compounds on W surface after $SF_6-N_2$ gas plasma treatment were examined by XPS and the concentration of F ions was detected by OES during plasma on.