• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.221-222
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• 2013

• 센서학회지
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• 제23권6호
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• pp.383-387
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• 2014

Electrically conductive polypyrrole-polyvinylpyrrolidone (PPy-PVP) nanofiber mats with a core-shell structure have been successfully fabricated by a two-step process: the formation of FeCl3-containing PVP nanofiber mat by electrospinning, and the vapor-phase polymerization (VPP) of pyrrole monomer on the mat in a sealed chamber at room temperature. Surface morphology and chemical composition of the PPy-PVP mat were characterized by SEM, EDX and FTIR analyses. The as-prepared nonwoven mat was composed of PPy-PVP nanofibers with an average diameter of 300 nm. The sheet conductivity of the nanofiber mat was measured to be approximately 0.01 S/cm by a four-point probe. We have also investigated gas-sensing properties of PPy-PVP nanofiber mat upon exposure to methanol vapor. The PPy-PVP nanofiber sensors were observed to have excellent methanol-sensing performance. The nanofiber-based core-shell nanostructure could give an opportunity to fabricate a highly sensitive and fast response sensor due to its high surfaceto-volume ratio.

• 센서학회지
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• 제23권1호
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• pp.42-45
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• 2014

Recently, tremendous application utilizing electrospun nanofibers have been actively reported due to its several advantages, such as high surface to volume ratio, simple fabrication and high-throughput manufacturing. In this paper, we developed highly sensitive and consistent nanofiber humidity sensor by electrospinning. The humidity sensor was fabricated by rapid electrospinning (~2 sec) $TiO_2$/PVP/LiCl mixed solution on the micro-interdigitated electrode. In order to evaluate the humidity sensing performances, we measured current response using DC bias voltage under various relative humidity levels. The results show fast response / recovery time and marginal hysteresis as well as long-term stability. In addition, with the aid of micro-interdigitated electrode, we can reduce a total resistance of the sensor and increase the total reaction area of nanofibers across the electrodes resulting in high sensitivity and enhanced current level. Therefore, we expect that the electrospun nanofiber array for humidity sensor can be feasible and promising for diverse humidity sensing application.

• BMB Reports
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• 제49권1호
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• pp.26-36
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• 2016

Emerging trends for cardiac tissue engineering are focused on increasing the biocompatibility and tissue regeneration ability of artificial heart tissue by incorporating various cell sources and bioactive molecules. Although primary cardiomyocytes can be successfully implanted, clinical applications are restricted due to their low survival rates and poor proliferation. To develop successful cardiovascular tissue regeneration systems, new technologies must be introduced to improve myocardial regeneration. Electrospinning is a simple, versatile technique for fabricating nanofibers. Here, we discuss various biodegradable polymers (natural, synthetic, and combinatorial polymers) that can be used for fiber fabrication. We also describe a series of fiber modification methods that can increase cell survival, proliferation, and migration and provide supporting mechanical properties by mimicking micro-environment structures, such as the extracellular matrix (ECM). In addition, the applications and types of nanofiber-based scaffolds for myocardial regeneration are described. Finally, fusion research methods combined with stem cells and scaffolds to improve biocompatibility are discussed. [BMB Reports 2016; 49(1): 26-36]

• 대한기계학회논문집A
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• 제38권8호
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• pp.875-880
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• 2014

최근에, 3 차원 인공지지체와 나노섬유는 골 조직 재생을 위해 개발되고 있다. 본 연구에서는, 나노-마이크로 정밀 분사 시스템을 이용하여 하이브리드 인공지지체를 제작하였다. 하이브리드 인공지지체는 마이크로 인공지지체와 나노섬유가 결합하여 제작되었으며, 마이크로 인공지지체와 나노섬유를 얻기 위해 자유 형상 제작 기술과 전기방사 기법이 사용되었다. 마이크로 인공지지체는 정밀한 공극을 고려하여 CAD/CAM 데이터 따라 자유 형상 제작 기술에 의해 제작되었으며, 제작 공정은 $100^{\circ}C$의 온도, 평균 650 kPa의 압력, 그리고 250 mm/sec의 Z 축 이송속도가 적용되었다. 그리고 전기방사법을 통하여 나노섬유를 제작함에 있어서 본 시스템에 적용한 공정 조건은, 5 kV의 전압, 0.1 ml/min의 유량, 그리고 1 mm의 노즐 팁과 콜렉터와의 거리로 설정하였다. 제작된 하이브리드 인공지지체는 MG-63 세포를 이용하여 세포 증식 실험을 진행하였다.

• Composites Research
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• 제26권1호
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• pp.14-20
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• 2013

CNT를 포함하는 전기방사된 PVDF를 작동기 제조의 소재로 사용하였다. 기계적, 전기적특성과 함께 작동기 성능을 평가하기 위해 전기화학적 환경 내에서 전기화학 및 작동기 거동을 조사하였다. 전기방사된 시트의 특징 중 하나인 유연함을 가지며 분산이 잘 되어 접촉면이 많은 이점이 있기 때문에 작동기 제작방법으로 적합하다고 생각되었다. 전기방사는 여러 가지 요인들로 방사형태가 각각 다르게 나타났다. 본 연구에서는 콜렉터를 드럼형태를 사용하여 방사된 나노섬유의 방향성을 가지게 하였으며 형태를 확인하기 위해 전자현미경을 통해 나노섬유가 정렬된 형상을 확인하였다. 전자침 X-ray 미세분석기를 사용하여 PVDF내에 CNT가 함침 되어 나노섬유가 정렬 된 상태를 확인하였으며, 이러한 형태가 미치는 기계적, 전기적 물성에 영향을 평가하기 위해 인장시험을 통해 인장강도와 전기 저항도를 측정하였다. 정렬된 방향의 나노섬유 시트가 정렬의 직각 방향의 시트보다 상대적으로 기계적 그리고 전기적 물성이 좋게 나타났다. 전기방사된 CNT/PVDF 나노섬유 시트가 작동기로 사용 되었을 때 캐스팅으로 제작된 PVDF 시트의 작동기보다 좋은 효율을 확인하기 위해 전기화학적 환경 내에서 작동기 시험을 진행하여, 작동기 효율과 전기적 용량을 측정하였다. 전기방사된 CNT/PVDF 나노섬유 시트는 CNT와 PVDF간의 접촉면이 많기 때문에, 우수한 작동성을 나타내었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.51.1-51.1
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• 2011

An electrospun Poly (lactice-co-glycolide acid) (PLGA) and Gelatin nanofiber tube was fabricated for potential intestinal stent application. Mechanical properties of tube were evaluated by tensile strength and burst strength tests. Physical and chemical properties were evaluated by contact angle measurement, swelling rates and porosity measurements. Biodegradability was investigated by immersion in simulated body fluid (SBF). Biocompatibility was investigated in vitro by cytotoxicity and proliferation studies by MTT assay, confocal microscopy and western blot using IEC-18 (Rat intestinal epithelial cell). After intestinal stent was implanted into rat bowel for periods from 7 to 10days, it was then analyzed using micro-computed tomography (Micro CT) and X-ray techniques. Futhermore, histological analysis was performed by hematoxylin-eosin (H&E) stain.

• 멤브레인
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• 제31권6호
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• pp.426-433
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• 2021

본 연구에서는 polyketone (PK)을 이용하여 전기방사 조건에 따른 섬유 형상의 특성 변화와 유수분리 가능성을 확인해 보았다. 고습과 저습 조건에서는 마이크론 직경의 섬유가 형성되었으며, 특히 고습에서는 섬유의 표면이 거칠게 변한 것이 확인되었다. 섬유 직경을 micro에서 nano로 변경하기 위하여 방사용액에 염을 추가하였으며, 그 결과 섬유 직경이 약 90% 감소하는 것을 확인할 수 있었다. 제조된 rPK-LNC와 PK-H로 유수분리 특성을 확인하기 위해 oil/water 에멀션으로 중력 조건에서 유수분리를 진행하였으며 total organic carbon (TOC)와 탁도를 측정하여 특성을 분석하였다. 제거율 확인결과 탁도가 TOC와 동일한 경향성을 나타내는 것이 확인되었다. 따라서 본 연구에서는 고분자의 방사조건과 염의 유무에 따른 분리막의 섬유 형상과 물리적 특성변화와 이를 이용한 유수분리 특성에 대해 연구하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.69-72
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• 2007

Cellulose is a beneficial material that has low cost, lightweight, high compatibility and biodegradability. Recently electroactive paper (EAPap) on cellulose base was discovered as a smart material and actuator through ion migration and piezoelectric effect. Furthermore cellulose has a potentiality to apply the display material, because of its high reflectivity, flexibility and high transmittance. The various shapes and height patterns of the Cellulose acetate (CA) solution, such as circle and honeycomb patterns, were fabricated and observed by field emission scanning electron microscope (FESEM, S4300 Hitachi). The resulting pattern showed uniform size in the large area without defect. After stretching the CA film with saponification process in the sodium methoxide in methanol solution, Most of the compositions become one directional ordered nanofibers below 50nm.

• 센서학회지
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• 제22권2호
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• pp.100-104
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• 2013

A superhydrophobic mesh is a unique structure that blocks water, while allowing gases, sound waves, and energy to pass through the holes in the mesh. This mesh is used in various devices, such as gas- and energy-permeable waterproof membranes for underwater sensors and electronic devices. However, it is difficult to fabricate micro- and nano-structures on three-dimensional surfaces, such as the cylindrical surface of a wire mesh. In this research, we successfully produced a superhydrophobic water-repellent mesh with a high contact angle (> $150^{\circ}$) for nanofibrous structures. Conducting polymer (CP) composite nanofibers were evenly coated on a stainless steel mesh surface, to create a superhydrophobic mesh with a pore size of $100{\mu}m$. The nanofiber structure could be controlled by the deposition time. As the deposition time increased, a high-density, hierarchical nanofiber structure was deposited on the mesh. The mesh surface was then coated with Teflon, to reduce the surface energy. The fabricated mesh had a static water contact angle of $163^{\circ}$, and a water-pressure resistance of 1.92 kPa.