• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.238-243
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• 2018

A nanofiber was fabricated with carbon nanotubes for transparent electrodes. It was prepared with a composite solution of bio-molecules polycaprolactone (PCL) and multiwalled carbon nanotubes (MWCNTs) by electrospinning on a glass substrate, following which its electrical characteristics were investigated. The content of MWCNTs was varied during electrospinning, while that of PCL was fixed. Further, a nanometer-thick thin film of silver was deposited on the nanofiber layer using a thermal evaporator to improve the electrical characteristics; the sheet resistance significantly reduced after this deposition. The results showed that this carbon nanotube nanofiber has potential applications in biotechnology and as a flexible transparent display material.

• 폴리머
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• 제38권4호
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• pp.518-524
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• 2014

용융전기방사법은 유기용매를 사용하지 않아 용액전기방사법에 비하여 친환경 기술로 관심을 받고 있다. 그러나 용융전기방사법으로 제작된 섬유의 직경은 수 마이크론에서 수십 마이크론에 이르고 있어 그 응용성에 제한을 받고 있다. 본 연구에서는 자체 제작한 용융전기방사 장비를 사용하여 용융점도에 따른 방사섬유의 직경의 변화를 체계적으로 연구하였다. 장비가 허용하는 온도 범위에서 방사 가능한 용융점도를 갖도록 저밀도 폴리에틸렌에 폴리에틸렌모노알콜과 폴리에틸렌 왁스를 혼합하여 실험에 사용하였다. 이 고분자 혼합물들을 사용하여 용융점도의 변화에 따라 수 마이크론에서 수십 마이크론까지의 크기를 가진 고른 표면의 섬유를 제조할 수 있었다. 또한 산화된 폴리에틸렌 왁스를 혼합물에 사용하여 고분자의 극성에 따른 직경의 변화를 관찰하였다. 부가적으로 인가 전압과 방사 거리 등이 방사섬유의 직경에 미치는 영향을 조사하였다.

• 폴리머
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• 제36권2호
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• pp.124-130
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• 2012

본 연구의 목적은 전기방사법을 사용하여 poly(L-lactide-$co$-${\varepsilon}$-caprolactone) (PLCL)과 marine collagen (MC)이 혼합된 나노섬유를 제조하는 것이다. 전기방사된 나노섬유의 직경과 형태는 여러 공정 변수에 의해서 변화되는데, PLCL과 MC의 혼합비, 노즐과 콜렉터와의 거리, 노즐의 직경, 용액의 방출 속도 그리고 전기장의 세기 변화에 따라 나노파이버의 직경을 주사전자현미경을 통해서 분석하였다. 또한 제조된 나노파이버의 표면변화를 확인하기 위해 물과의 접촉각을 측정하였으며, 나노파이버의 세포 친화성을 평가하기 위해 MG-63을 이용하여 생존율과 흡착형태를 주사전자현미경과 형광현미경을 통해서 관찰하였다. 이와 같은 연구 결과, 방사거리, MC의 함량, 전기장의 세기가 증가할수록 제조된 나노파이버의 평균직경은 감소하는 경향을 나타냈다. 또한 MC의 함량이 증가할수록 나노파이버의 친수성이 증가하였고 세포독성은 관찰되지 않았다. 이에 따라 해양유래 생물에서 추출한 콜라겐은 조직공학용 소재에 새롭게 사용될 수 있을 것으로 예상된다.

• 멤브레인
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• 제16권1호
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• pp.1-8
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• 2006

나노섬유란 $1{\mu}m$ 이하의 섬유를 의미하며 멜트블로운(Melt blown), 복합방사, 분할방사, 전기방사 등의 방법으로 제조된다. 나노섬유는 초극세 섬유로서 섬유의 생성과 동시에 3차원의 네트워크로 융착되어 적층된 형태의 다공성 웹은 초박막, 초경량이며 기존 섬유에 비해 부피 대비 표면적비가 지극히 높고, 높은 기공도를 지니고 있다. 이러한 특성으로 인해 가스나 액체로부터 미세입자를 분리하는 고효율 초기능성 필터 소재로 활용될 수 있으며, 나노섬유로 구성된 필터는 여과 효율이 높고 공극율이 매우 높아 필터에서 발생하는 압력강하가 적다. 또한 공정의 적용이 용이하여 기존의 부직포 등의 소재에 코팅이 가능하므로, 나노섬유 필터는 기존 부직포 필터 시장의 대부분을 대체할 것으로 기대되어 진다. 본 총설에서는 나노섬유 필터의 연구개발 동향과 공업적 제조기술의 문제점 및 향후 시장성에 대해서 고찰하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.2.1-2.1
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• 2011

Biomedical applications of electrospun nanofibrous meshes have been receive tremendous attentions because of their unique structures and versatilities as novel biomaterials. Incorporation of growth factors in fibrous meshes can be performed by surface-modification and encapsulation. Those growth factors stimulate differentiation and proliferation of specific types of cells and thus lead tissue regenerations of specific cell types. Topographical cues of electrospun nanofibrous meshes also increase differentiation of specific cell types according to alignments of fibrous structures. Wound healing treatments of diabetic ulcers were performed using nanofibrous meshes encapsulating multiple growth factors. Aligned nanofibrous meshes and those with random configuration were compared for differentiating mesenchymal stem cells into neuronal cells. Thus, nanofibrous meshes can be applied to novel drug delivery carriers and matrix for promoting cellular proliferation.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.1.1-1.1
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• 2011

Electrospinning has known to be very effective tool for production of versatile one-dimensional (1D) nanostructured materials such as nanofibers, nanorod, and nanotubes and for easily assembly to two-, three-dimensional(2D, 3D) nanostructures such as thin film, membrane, and nonwoven web, etc. We have studied on the electrospinning technology for novel energy storage and conversion materials such as advanced separator, dye sensitized solar cell, supercapacitor, etc. High heat-resistive nanofibrous membrane as a new separator for future lithium ion polymer battery was prepared by electrospinning of PVdF based composite solution. The novel nanofibrous composite nonwovens have tensile strength of above 50 MPa and modulus of above 1.3 GPa. The internal structure of the electrospun composite nanofiber with a diameter of few hundreds nanometer were composed of core-shell nanostructure. And also electrospun $TiO_2$ nanorod/nanosphere based dye-sensitized solar cells with high efficiency are successfully prepared. Some battery performance will be introduced.

• 한국정밀공학회지
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• 제29권3호
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• pp.339-345
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• 2012

Electrospun meshed poly-caprolactone PCL was patterned by femtosecond laser with linear grooves. As parametric variables, focus spot size, pulse energy, and scanning speed were varied to determine the affects on groove size and the characteristics of the electrospun fiber at the edges of these grooves. The femtosecond laser was seen to be an effective means for flexibly structuring the surface of ES PCL scaffolds and the width of the ablated grooves was well controlled by laser energy and focus spot size. The ablation threshold was measured to be $14.9J/cm^2$ which is a little higher than other polymers. These affects were attributed to optical multiple reflections inside nano-fibers. By the laser-induced plasma at higher pulse energies, some melting of fibers was observed.

• 한국전기전자재료학회논문지
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• 제28권4호
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• pp.252-256
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• 2015

In this study, we propose a novel fabrication of an oxide-based lateral thermoelectric pn couple and investigate the characteristics of the thermoelectric couple. Electrospun ZnO and $LaSrCoO_3$ nanofibers are used as n- and p-legs of the couple, respectively. The Seebeck coefficients of the n- and p-type nanofibers and the pn couple are $-98.1{\mu}V/K$, $42.4{\mu}V/K$, and $118.8{\mu}V/K$, respectively. The thermoelectric couple generates an output voltage of $484.7{\mu}V$ at a temperature difference of 4.1 K.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.219.2-219.2
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• 2011

The oxyfluorination effects of electrospun carbon nanofibers (OFACFs) were investigated for $CO_2$ storage. Carbon nanofibers were prepared form poly acrylonitrile / N,N-dimethylformamide solution through electrospinning method and heat treatment. Chemical activation of carbon nanofibers were carried out in order to improve the pore structure. And the surface modification of activated carbon nanofibers was conducted by oxyfluorination to improve the $CO_2$ storage on effect of introduced functional groups. The samples were labeled CF (electrospun carbon nanofiber), ACF (activated carbon nanofibers), OFACF-1 ($F_2:O_2$ = 3:7), OFACF-2 ($F_2:O_2$ = 5:5) and OFACF-3 ($F_2:O_2$ = 7:3). The functional group of OFACFs was investigated by x-ray photoelectron spectroscopy analysis. The specific surface area, pore volume and pore size of OFACFs were calculated and pore shape was estimated by the BET equation. Through the adsorption isotherm, the specific surface area and pore volume significantly decreased by oxyfluorination.

• Macromolecular Research
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• 제13권1호
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• pp.73-79
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• 2005

Poly(L-lactic acid-co-succinic acid-co-l,4-butane diol) (PLASB) was synthesized by direct condensation copolymerization of L-lactic acid (LA), succinic acid (SA), and 1,4-butanediol (BD) in the bulk using titanium(IV) butoxide as a catalyst. The weight-average molecular weight ofPLASB was $2.1{\times}10^{5}$ when the contents of SA and BD were each 0.5 mol/100 mol of LA. Electrospinning was used to fabricate porous membranes from this newly synthesized bioabsorbable PLASB dissolved in mixed solvents of methylene chloride and dimethylformamide. Scanning electron microscopy (SEM) images indicated that the fiber diameters and nanostructured morphologies of the electrospun membranes depended on the processing parameters, such as the solvent ratioand the polymer concentration. By adjusting both the solvent mixture ratio and the polymer concentration, we could fabricate uniform nanofiber non-woven membranes. Cell proliferation on the electrospun porous PLASB membranes was evaluated using mouse fibroblast cells; we compare these results with those of the cell responses on bulk PLASB films.