• 센서학회지
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• 제17권4호
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• pp.281-288
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• 2008

Polyacrylonitrile(PAN)/metal oxide(MO) nanocomposite mats with a thickness of 0.12 mm were electrospun by adding 0 to 10 wt% of MO nanoparticles ($Fe_2O_3$, ZnO, $SnO_2$, $Sb_2O_3-SnO_2$) into PAN. Pt electrode was patterned on $Al_2O_3$ substrate by DC sputtering and then the PAN(/MO) mats on the Pt patterned $Al_2O_3$ were electrically wired to investigate the $CO_2$ gas sensing properties. As the MO content rose, the fiber diameter decreased due to the presence of lumps caused by the presence of MOs in the fiber. The PAN/2% ZnO mat revealed a faster response time of 93 s and a relatively short recovery of 54 s with a ${\Delta}R$ of 0.031 M${\Omega}$ at a $CO_2$ concentration of 200 ppm. The difference in sensitivity was not observed significantly for the PAN/MO fiber mats in the $CO_2$ concentration range of 100 to 500 ppm. It can be concluded that an appropriate amount of MO nanoparticles in the PAN backbone leads to improvement of the $CO_2$ gas sensing properties.

• 한국의류학회지
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• 제41권1호
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• pp.131-140
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• 2017

Uniform nanofibers of polyurethane with different content of Juniperus Chinensis extracts (JCE) were successfully prepared by the electrospinning method. We investigated physiochemical properties of prepared compound nanoweb according to various concentrations of Juniperus Chinensis extracts using a Fourier transform infrared (FT-IR) spectrometer, X-ray diffractometer (XRD), thermogravimeter (TGA), and differential scanning calorimeter (DSC). The antibacterial activity of the JCE loaded PU nanofiber was conducted using the disk diffusion test against Gram-positive and Gram-negative bacteria. JCE was induced in the infrared spectra in the absorption band of PU/JCE nanowebs at $3,300cm^{-1}$, $2,960cm^{-1}$, $1,400-1,600cm^{-1}$, and $1,050cm^{-1}$. Thermal stability decreased with increasing JCE content in the PU/JCE nanowebs. The DSC curve of the PU nanoweb shows an endotherm peak at $420^{\circ}C$; in addition, the peak also became smaller and broader with increasing JCE content. The diffraction intensities of PU observed at 2 theta of $20^{\circ}$ decreased with the increasing amount of JCE in the compound nanoweb. In addition, the crystal intensities of the compound nanowebs also decreased along with the JCE content. Structural analysis indicates that JCE and PU are miscible. Juniperus Chinensis incorporated PU nanofibers demonstrated excellent antibacterial properties against both Gram-positive and Gram-negative bacteria.

• 한국화재소방학회논문지
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• 제30권6호
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• pp.9-13
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• 2016

본 논문에서는 내산화성 및 난연성이 향상된 폴리우레탄 나노섬유를 전기방사법 및 수산화알루미늄 내첨을 통해 제조하였다. 전기방사 조건은 인가전압: 20 kV, 폴리머 용액 유량: 1.2 ml/h, 롤러 속도: 120 rpm 및 롤러와 주사기 팁의 거리: 15 cm의 공정변수에서 최적의 조건을 확인하였다. 폴리우레탄 섬유의 내산화성 및 난연성을 향상시키기 위하여, 수산화알루미늄을 전기방사 시 내첨하였다. 제조된 샘플의 열적 특성을 평가하기 위하여 열중량분석기(thermogravimetric analysis, Shimadzu, TGA-50H)를 사용하였다. 또한 관련 분석을 통해 고분자 분해 온도(polymer decomposition temperature), 적분열분해 진행온도(integral procedure decomposition temperature), 최종 분해 온도(final decomposition temperature) 및 열분해 후 잔여량 등을 분석하였다. 그리고 분해 반응의 속도론적 고찰을 위해 Horowitz-Metzger 적분식을 통해 활성화 에너지를 해석하였다. 수산화알루미늄의 내첨에 의해, 분해 활성화 에너지가 50% 이상 증가함을 확인하였다. 이는 수산화알루미늄이 $300{\sim}500^{\circ}C$에서 열분해함에 따라 수화반응에 의해 폴리우레탄 나노섬유의 열분해 저항성이 커지기 때문인 것으로 파악된다.

• 센서학회지
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• 제25권3호
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• pp.223-228
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• 2016

In this work, we prepared porous WO3 nanofibers (NFs) functionalized by bio-inspired catalytic $Cr_2O_3$ and $Co_3O_4$ nanoparticles as highly sensitive and selective $H_2S$ gas sensing layers. Highly porous 3-dimensional (3D) NFs networks decorated by well-dispersed catalyst NPs exhibited superior $H_2S$ gas response ($R_{air}/R_{gas}$ = 46 at 5 ppm) in high humidity environment (95 %RH). In particular, the sensors showed outstanding $H_2S$ selectivity against other interfering analytes (such as acetone, toluene, CO, $H_2$, ethanol). Exhaled breath sensors using $Cr_2O_3$ and $Co_3O_4$ catalysts-loaded $WO_3$ NFs are highly promising for the accurate detection of halitosis.

• 센서학회지
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• 제23권3호
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• pp.211-215
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• 2014

The Pt-, Ni- and Cr-decorated tubular $SnO_2$ nanofibers for gas sensors were prepared by the electrospinning of polyvinylpyrrolidone (PVP) nanofibers containing Pt, Ni, and Cr precursors, the sputtering of $SnO_2$ on the electrospun PVP nanofibers, and the removal of sacrificial PVP parts by heat treatment at $600^{\circ}C$ for 2 h. Pt-decorated tubular $SnO_2$ nanofibers showed high response ($R_a/R_g=210.5$, $R_g$: resistance in gas, $R_a$: resistance in air) to 5 ppm $C_2H_5OH$ at $350^{\circ}C$ with negligible cross-responses to other interference gases (5 ppm trimethylamine, $NH_3$, HCHO, p-xylene, toluene and benzene). Cr-decorated tubular $SnO_2$nanofibers showed the selective detection of p-xylene at $400^{\circ}C$. In contrast, no significant selectivity to a specific gas was found in Ni-decorated tubular $SnO_2$ nanofibers. The selective and sensitive detection of gases using Pt-decorated and Cr-decorated tubular $SnO_2$ nanofibers were discussed in relation to the catalytic promotion of gas sensing reaction.

• Macromolecular Research
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• 제17권11호
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• pp.850-855
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• 2009

Keratin is an important protein used in wound healing and tissue recovery. In this study, keratin was modified chemically with iodoacetic acid (IAA) to enhance its solubility in organic solvent. Poly(hydroxybutylate-co-hydroxyvalerate) (PHBV) and modified keratin were dissolved in hexafluoroisopropanol (HFIP) and electrospun to produce nanofibrous mats. The resulting mats were surface-characterized by ATR-FTIR, field-emission scanning electron microscopy (FE-SEM) and electron spectroscopy for chemical analysis (ESCA). The pure m-keratin mat was cross-linked with glutaraldehyde vapor to make it insoluble in water. The biodegradation test in vitro showed that the mats could be biodegraded by PHB depolymerase and trypsin aqueous solution. The results of the cell adhesion experiment showed that the NIH 3T3 cells adhered more to the PHBV/m-keratin nanofibrous mats than the PHBV film. The BrdU assay showed that the keratin and PHBV/m-keratin nanofibrous mats could accelerate the proliferation of fibroblast cells compared to the PHBV nanofibrous mats.

• 폴리머
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• 제32권5호
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• pp.409-414
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• 2008

전기방사법으로 이온염을 함유하는 TFE/증류수 혼합용매를 이용하여 젤라틴 나노섬유를 제조하였으며, 얻어진 나노섬유의 평균직경은 $110{\sim}125\;nm$였다. 이온염의 농도가 증가할수록 비드의 발생이 줄어들고 균일한 나노섬유 제조가 가능하였다. 이는 이온염의 첨가에 의한 젤라틴 용액의 점도 및 전도도가 증가함에 기인하는 것으로 확인되었다. 특히 일가이온보다 이가이온을 사용할 경우 점도 및 전도도의 증가에 더 효과적이었으며 이들 이온염은 분자간 소수성 상호작용뿐만 아니라 젤라틴 분자의 입체구조 정렬에도 영향을 주었다. 그러나 이온염 농도에 따른 나노섬유의 직경변화는 관찰되지 않았다. 제조된 나노섬유를 이용한 XRD분석 결과 이온염의 농도가 증가할수록 젤라틴 분자의 재결정화에 의해 나노섬유의 결정화도가 높아졌다.

• 한국분말재료학회지
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• 제28권3호
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• pp.259-266
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• 2021

The (Ga_1-xZn_x)(N_1-xO_x) solid solution is attracting extensive attention for photocatalytic water splitting and wastewater treatment owing to its narrow and controllable band gap. To optimize the photocatalytic performance of the solid solution, the key points are to decrease its band gap and recombination rate. In this study, (Ga_1-xZn_x)(N_1-xO_x) nanofibers with various Zn fractions are prepared by electrospinning followed by calcination and nitridation. The effect of the composition and crystallinity of electrospun oxide nanofibers on the morphology and optical properties of the obtained solid-solution nanofibers are systematically investigated. The results show that the final shape of the (Ga_1-xZn_x) (N_1-xO_x) material is greatly affected by the crystallinity of the oxide nanofibers before nitridation. The photocatalytic properties of (Ga_1-xZn_x)(N_1-xO_x) with different Ga:Zn atomic ratios are investigated by studying the degradation of rhodamine B under visible light irradiation.

• 한국진공학회지
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• 제22권3호
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• pp.156-161
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• 2013

연속적인 1차원의 나노섬유를 제작하는데 빠르고 효과적인 방법인 전기방사법을 이용하여 Ag 나노섬유로 이루어진 투명전극을 제작하고 그 특성을 측정하였다. 전기방사를 통해 제조된 Ag 나노섬유는 큰 종횡비를 갖게 되며 열처리를 통해 생성된 섬유사이의 fused junction이 접촉저항을 낮추어 전기적 특성을 향상시킨다. Ag/고분자 용액을 졸-겔 방법을 이용하여 제조한 후 glass 기판위에 방사시켜 Ag/고분자 나노섬유 구조체를 제작하고 $200{\sim}500^{\circ}C$, 2시간 열처리하여 고분자가 일정부분 제거되고 전도성이 향상된 Ag 나노섬유 투명전극을 제조하였다. Ag 나노섬유의 모폴로지를 FE-SEM을 통해 확인하였고 Ag 나노섬유 투명전극의 투과도와 면저항을 UV-vis-NIR spectroscopy와 I-V특성 측정장치를 사용하여 측정하였다. 투과도 83%에서 면저항 $250{\Omega}/sq$의 투명전극을 제작하였으며 전도성필름에 적합한 수준이다. Ag 나노섬유로 이루어진 투명 전극은 전기적, 광학적, 기계적 특성이 우수하여 차세대 유연 디스플레이에 적용 가능성을 보여준다.

• 전기화학회지
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• 제5권3호
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• pp.117-124
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• 2002

PAN(polyacrylonitrile)을 DMF(dimethylformamide) 용매에 용해하여 정전방사법에 의해 평균 직경 400 nm의 나노섬유 웹을 제조하였다. 제조된 나노섬유 웹은 산화 안정화, 활성화 공정을 거쳐 활성화 탄소 나노섬유를 제조하여, 전기화학적 특성과 비축전 용량을 측73하였다. 활성화 탄소 나노섬유의 비표면적은 $1230m^2/g-800m^2/g$으로 일반 활성탄소 섬유의 거동과는 다르게 활성화 온도가 증가할수록 감소하는 경향을 나타냈으며, 활성화 에너지 값은 29.2kJ/mol로 활성화 온도에 크게 영향을 받지 않고, 급격한 반응이 일어남을 알 수 있었다. 비축전 용량은 활성화 온도가 $700^{\circ}C,\;750^{\circ}C,\;800^{\circ}C$의 경우 27 F/g, 25 F/g, 22 F/g으로 활성화 온도가 증가할수록 비표면적에 비례하여 낮아지는 경향을 나타냈다.