• Membrane and Water Treatment
• /
• 제10권6호
• /
• pp.417-429
• /
• 2019

Poly Sulfone nanofibers were electrospun to fabricate membranes of different characteristics. To fabricate the fiber mats, polymer concentration, flowrate, and current density were determined as the most influencing factors affecting the overall performance of the membranes and studied through Response Surface Methodology. The Box-Behnken Design method (three factors at three levels) was used to design, analyze, and optimize the parameters to achieve the best possible performance of the electrospun membranes in forward osmosis process. Also, internal concentration polarization that characterizes the efficiency of the forward osmosis membranes was determined to better assess the overall performance of the fabricated electrospun membranes. Water flux to reverse salt flux was considered as the main response to assess the performance of the membranes. As confirmed experimentally, best membrane performance with the minimal structural parameter value could be achieved when predicted optimal values were used to fabricate the membranes through electrospinning process.

• 멤브레인
• /
• 제20권1호
• /
• pp.40-46
• /
• 2010

본 연구에서는 내열성 고분자인 폴리에테르술폰을 이용하여 전기방사의 방법으로 섬유 형태의 다공성 막을 제조하였다. 여기에 Nafion 용액을 함침 시켜 고분자 전해질 연료전지용 막을 제조하였다. 열중량 분석을 통해, 현재 고분자 전해질 막으로 상용화되어 널리 쓰이고 있는 Nafion 212보다 더 높은 열적 안정성을 갖는 것을 확인하였다. 주사전자현미경 측정을 통하여, 다공성의 폴리에테르술폰 막에 Nafion 용액이 수소이온 전도체로서 잘 함침 되어 있음을 확인할 수 있었다. AC impedance 측정 결과, $100^{\circ}C$ 이하의 온도범위에는 수소 이온 전도도가 $10^{-2}$ S/cm로 나왔으며, $100^{\circ}C$ 이상의 범위에서는 $10^{-3}$ S/cm의 값을 나타냈다. 0.6 V, $90^{\circ}C$의 조건에서 389 mA/$cm^2$의 전류밀도를 나타내었다. Nafion 212 상용 막이 $75^{\circ}C$에서 최대 성능을 나타내는데 반해, Nafion 용액을 함침시킨 폴리에테르술폰 막은 $90^{\circ}C$에서 최대 성능을 갖는 것으로 나타났다.

• 한국수소및신에너지학회논문집
• /
• 제33권2호
• /
• pp.164-175
• /
• 2022

In this work, sulfonated poly (ether ether ketone) (SPEEK) composite membranes including strontium zirconate (SrZrO₃) were fabricated by the electrospinning method. Fourier-transform infrared spectroscopic analysis and X-ray diffraction analysis were used to identify the chemical structure and the crystallinity of SrZrO₃ and electrospun composite membranes. The thermal stability of the pure SPEEK and SPEEK/SrZrO₃ electrospun composite membranes were investigated by using thermogravimetric analysis. The physicochemical properties and proton conductivity were enhanced with the addition of different weight ratio of SrZrO₃ nanofiller (2, 4 and 6 wt%) in SPEEK polymer. The optimized SPEEK/SrZrO₃-4 electrospun membrane containing 4 wt% of SrZrO₃ showed a high proton conductivity compared to other electrospun SPEEK/SrZrO₃ composite membranes. The results indicate that electrospun composite membranes incorporating these perovskite nanofillers should be explored as potential candidates for use in proton exchange membrane fuel cells.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2008년도 춘계 총회 및 학술발표회
• /
• pp.261-263
• /
• 2008

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

• 전기화학회지
• /
• 제19권1호
• /
• pp.9-13
• /
• 2016

Electrospun poly(ether sulfone) (PES) membrane impregnated with Nafion (PES-N) have been developed for high-temperature polymer-electrolyte membrane fuel cell (HT-PEMFC). The PES-N obtains highly thermal stability up to $430^{\circ}C$, which is higher than that of the commercial Nafion 212. The PES-N membrane shows a good proton conductivity of about $10^{-2}S\;cm^{-1}$ in a temperature range from $75^{\circ}C$ to $120^{\circ}C$. The membrane-electrode assembly (MEA) with the PES-N membrane exhibits a current density of $1.697A\;cm^{-2}$ at $75^{\circ}C$, and $0.813A\;cm^{-2}$ at $110^{\circ}C$ when the applied voltage is 0.6 V, whereas the MEA with the Nafion 212 membrane shows the current density of $0.647Acm^{-2}$ at $110^{\circ}C$. The results suggest that the PES-N can be a good candidate for a polymer electrolyte membrane of the HT-PEMFC.

• 한국수소및신에너지학회논문집
• /
• 제22권5호
• /
• pp.569-578
• /
• 2011

The $SiO_2$ membranes for polymer electrolyte membrane fuel cell (PEMFC) are preapared by electrospinning method. It leads to high porosity and surface area of membrane to accommodate the proton conducting materials. The composite membrane was prepared by impregnating of Nafion ionomer into the pores of electrospun $SiO_2$ membranes. The $SiO_2$:heteropolyacid (HPA) nano-particles as a inorganic proton conductor were prepared by microemulsion process and the particles are added to the Nafion ionomer. The characterization of the membranes was confirmed by field emission scanning electron microscope (FE-SEM), thermogravimetry analysis (TGA), and single cell performance test for PEMFC. The Nafion impregnated electrospun $SiO_2$ membrane showed good thermal stability, satisfactory mechanical properties and high proton conductivity. The addition of the $SiO_2$:HPA nano-particle improved proton conductivity of the composite membrane, which allow further extension for operation temperature in low humidity environments. The composite membrane exhibited a promising properties for the application in high temperature PEMFC.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제36권6호
• /
• pp.239-246
• /
• 2014

Many kinds of membrane have been used for the guided bone regeneration (GBR) technique. However, most membranes do not fulfill all requirements for the ideal membrane for the GBR technique. Among them, collagen membrane has been most widely used. However, its high price and weak tensile strength in wet condition are limitations for wide clinical application. Synthetic polymers have also been used for the GBR technique. Recently, silk based membrane has been considered as a membrane for the GBR technique. Despite many promising preclinical data for use of a silk membrane, clinical data regarding the silk membrane has been limited. However, silk based material has been used clinically as vessel-tie material and an electrospun silk membrane was applied successfully to patients. No adverse effect related to the silk suture has been reported. Considering that silk membrane can be provided to patients at a cheap price, its clinical application should be encouraged.

• 한국결정성장학회지
• /
• 제24권1호
• /
• pp.33-40
• /
• 2014

전기방사법(Electrospinning technique)을 이용하여 PVdF-HFP(Poly vinylidene fluoride-co-hexafluoropropylene) 멤브레인을 제조하고, 그 멤브레인 표면위에 DLC(Diamond-like carbon) 코팅공정을 적용하여 멤브레인의 표면변화 및 접촉각 변화를 조사하였다. Ar 플라즈마 처리시간 및 처리조건에 따라 PVdF-HFP 멤브레인 파이버 표면이 주름(wrinkles)형태로 변화 하였다. 이러한 Ar 플라즈마 처리가 된 PVdF-HFP 멤브레인은 초친수성(super-hydrophilic) 특성으로 변했지만, 초친수성 PVdF-HFP 멤브레인에 DLC 코팅공정을 적용하면 반대로 초소수성(super-hydrophobic) 특성으로 변화되었다. 이러한 특성을 가진 표면을 접촉각 측정과 XPS, FE-SEM 측정으로 분석하였다. 따라서 화학적 조성과 표면 형상에 의해 접촉각 특성을 가지는 것으로 확인하였다.

• 멤브레인
• /
• 제32권2호
• /
• pp.133-139
• /
• 2022

화석연료의 사용에 따른 지구 온난화 및 기상 이변으로 인하여 온실가스 저감 문제가 대두되고 있으며, 그에 따라 에너지 소모 없이 셀프 쿨링이 가능한 소재에 대한 연구가 활발히 진행되고 있다. 그 중에서도 실크는 천연 쿨링 소재로 알려져 있으나, 기존의 혼합 공정에서는 실크를 화학적으로 분말화 시키기 때문에 복사 냉각 효과가 사라지는 문제점이 있어, 복사냉각을 위한 필름 또는 코팅제 형태로 제조하는데 어려움을 겪고 있다. 본 연구에서는 실크 피브로인의 고유구조를 훼손하지 않는 물리적 분쇄 공정을 거친 실크 분말을 사용하여 다양한 형태의 막을 제조하고, 코팅제로서의 적용가능성을 살펴보고자 연구를 수행하였다. 이를 위해 실크 피브로인 분말이 도입된 전기방사 복합막 및 평막 형태의 복합막을 제조하였으며, 용액의 점도가 막 제조 및 제조된 막의 물성에 큰 영향을 미치는 것을 관찰하였다.