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 중 력 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.

Volatile organic compounds (VOCs) are a source of air pollution and are harmful to both human health and the environment. In this study, we fabricated polyurethane/rare earth (PU/RE) composite nanofibrous membranes via electrospinning with the aim of removing VOCs from air. The morphological structure of PU/RE nanofibrous mats were investigated using FE-SEM, EDX, and XRD experimental analyses. A certain amount of RE (up to 50 wt% compared to PU pellets) particles could be loaded on/into PU fibers. The PU nanofiber containing 50 wt% RE powder had the smallest fiber diameter of 356 nm; it also showed the highest VOCs absorption capacity compared with other composite membranes, having an absorption capacity about 3 times greater than pure PU nanofibers. In addition, all of the PU/RE nanofibrous membranes readily absorbed styrene the most, followed by xylene, toluene, benzene and chloroform. Therefore, the PU/RE nanofibrous membrane can play an important role in removing VOCs from the air, and its development prospects are impressive because they are emerging materials.

연구에서는, 전기방사법을 이용하여 산화철-산화그래핀(Fe3O4/GO, metallic graphene oxide; MGO)이 도입된 PVdF/MGO 복합나노섬유(PMG)를 제조하였으며, 이를 활용하여 비소제거에 대한 특성 평가를 진행하였다. MGO의 경우 In-situ-wet chemical 방법으로 제조하였으며, FT-IR, XRD분석을 진행하여, 형태와 구조를 확인하였다. 나노섬유 분리막의 기 계적 강도 개선을 위하여 열처리과정을 진행하였으며, 제조된 분리막의 우수한 기계적 강도 개선 효과를 확인할 수 있었다. 그러나, PMG 막의 경우, 도입된 MGO의 함량이 증가할수록 기계적 강도가 감소되는 경향성을 보여주었으며, 기공크기 분석 결과로부터, 0.3~0.45 μm의 기공크기를 가진 다공성 분리막이 제조되었음을 확인할 수 있었다. 수처리용 분리막으로의 활용 가능성 조사를 위해, 수투과도 분석을 실시하였다. 특히, PMG2.0 샘플의 경우 0.3 bar 조건에서, PVdF 나노섬유막(91 kg/m2h)에 비해 약 70% 향상된 결과값(153 kg/m2h)을 나타내었다. 또한, 비소 흡착실험 결과로부터, PMG 막의 경우, 비소3 가와 5가에 최대 81%, 68%의 높은 제거율을 보여주었으며, 흡착등온선 분석으로부터, 제조된 PMG 막의 경우 비소3가, 5가 모두 Freundlich 흡착거동을 따른다는 것을 확인하였다. 위 모든 결과로부터, PVdF/MGO 복합 나노섬유 분리막은 비소제거 및 수처리용 분리막으로 충분히 활용할 수 있을 것으로 판단된다.

Poly(meta-phenylene isophthalamide)(m-Aramid)는 우수한 강도, 내화학성, 내열성이 우수하다는 특성을 지니고 있다. 이러한 특성을 섬유 직경이 수십에서 수백나노의 멤브레인(Membrane)을 제조할 수 있는 전기방사법을 이용하면 미세한 구멍(Pore)을 가지게 되어 수처리 분야에 사용하기 적합하다. 본 연구에서는 m-Aramid 용액을 전기방사법을 이용하여 멤브레인을 제조하였다. 여러 섬유 평균직경의 나노섬유상 멤브레인을 제조하고, 중금속 흡착능을 지닌 보혜마이트(Boehmite)를 도입하여, 섬유 평균 직경에 따른 수투과유량(Flux)와 입자제거 효율 및 중금속 흡착성능을 평가하였다.

Zein/Poria cocos extract nanofibers were prepared based on the electrospinning of aqueous solutions with different Poria cocos extract concentrations (0, 5, 10, and 15 wt.%). The electrospinning parameters, including the polymer contents, voltage, and tip-to-collector distance (TCD), were optimized for the fabrication process. The resulting electrospun materials were all characterized using field-emission scanningelectron microscopy (FE-SEM). The diameters of the electrospun zein nanofibers were found to increase when increasing the zein concentration.

Sb-doped SnO2(ATO) thin films were prepared using electrospinning. To investigate the optimum properties of the electrospun ATO thin films, the deposition numbers of the ATO nanofibers(NFs) were controlled to levels of 1, 2, 4, and 6. Together with the different levels of deposition number, the structural, chemical, morphological, electrical, and optical properties of the nanofibers were investigated. As the deposition number of the ATO NFs increased, the thickness of the ATO thin films increased and the film surfaces were gradually densified, which affected the electrical properties of the ATO thin films. 6 levels of the ATO thin film exhibited superior electrical properties due to the improved carrier concentration and Hall mobility resulting from the increased thickness and surface densification. Also, the thickness of the samples had an effect on the optical properties of the ATO thin films. The ATO thin films with 6 deposited levels displayed the lowest transmittance and highest haze. Therefore, the figure of merit(FOM) considering the electrical and optical properties showed the best value for ATO thin films with 4 deposited levels.

We synthesized Fe-doped TiO2/α-Fe2O3 core-shell nanowires(NWs) by means of a co-electrospinning method anddemonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of thesamples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectronspectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained aftercalcination at 500oC exhibited core/shell NWs consisting of TiO2 in the core region and α-Fe2O3 in the shell region. In addition,the XPS results confirmed the formation of Fe-doped TiO2 by the doping effect of Fe3+ ions into the TiO2 lattice, which canaffect the ferromagnetic properties in the core region. For comparison, pure α-Fe2O3 NWs were also fabricated using anelectrospinning method. With regard to the magnetic properties, the Fe-doped TiO2/α-Fe2O3 core-shell NWs exhibited improvedsaturation magnetization(Ms) of approximately ~2.96emu/g, which is approximately 6.1 times larger than that of pure α-Fe2O3NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the TiO2lattice, the size effect of the Fe2O3 nanoparticles, and the structural effect of the core-shell nanostructures.

Flake-like LiCoO2 nanopowders were fabricated using electrospinning. To investigate their formation mech-anism, field-emssion scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carriedout. Among various parameters of electrospinning, we controlled the molar concentration of the precursor and the PVPpolymer. When the molar concentration of lithium and cobalt was 0.45 M, the morphology of LiCoO2 nanopowders wasirregular and round. For 1.27 M molar concentration, the LiCoO2 nanopowders formed with flake-like morphology. Forthe PVP polymer, the molar concentration was set to 0.011 mM, 0.026 mM, and 0.043 mM. Irregular LiCoO2 nanop-owders were formed at low concentration (0.011 mM), while flake-like LiCoO2 were formed at high concentration(0.026 mM and 0.043 mM). Thus, optimized molar concentration of the precursor and the PVP polymer may be relatedto the successful formation of flake-like LiCoO2 nanopowders. As a results, the synthesized LiCoO2 nanopowder can beused as the electrode material of Li-ion batteries.

Well-distributed SnO2-Sn-Ag3Sn nanoparticles embedded in carbon nanofibers were fabricated using a co-electrospinning method, which is set up with two coaxial capillaries. Their formation mechanisms were successfully demonstrated. The structural, morphological, and chemical compositional properties were investigated by field-emission scanning electron spectroscopy (FESEM), bright-field transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In particular, to obtain well-distributed SnO2 and Sn and Ag3Sn nanoparticles in carbon nanofibers, the relative molar ratios of the Ag precursor to the Sn precursor including 7 wt% polyacrylonitrile (PAN) were controlled at 0.1, 0.2, and 0.3. The FESEM, bright-field TEM, XRD, and XPS results show that the nanoparticles consisting of SnO2-Sn-Ag3Sn phases were in the range of ~4 nm-6 nm for sample A, ~5 nm-15 nm for sample B, ~9 nm-22 nm for sample C. In particular, for sample A, the nanoparticles were uniformly grown in the carbon nanofibers. Furthermore, when the amount of the Ag precursor and the Sn precursor was increased, the inorganic nanofibers consisting of the SnO2-Sn-Ag3Sn nanoparticles were formed due to the decreased amount of the carbon nanofibers. Thus, well-distributed nanoparticles embedded in the carbon nanofibers were successfully synthesized at the optimum molar ratio (0.1) of the Ag precursor to the Sn precursor after calcination of 800˚C.

We report on the NO gas sensing properties of non-directional ZnO nanofibers synthesized using a typical electrospinning technique. These non-directional ZnO nanofibers were electrospun on an SiO2/Si substrate from a solution containing poly vinyl alcohol (PVA) and zinc nitrate hexahydrate dissolved in distilled water. Calcination processing of the ZnO/PVA composite nanofibers resulted in a random network of polycrystalline ZnO nanofibers of 50 nm to 100 nm in diameter. The diameter of the nanofibers was found to depend primarily on the solution viscosity; a proper viscosity was maintained by adding PVA to fabricate uniform ZnO nanofibers. Microstructural measurements using scanning electron microscopy revealed that our synthesized ZnO nanofibers after calcination had coarser surface morphology than those before calcination, indicating that the calcination processing was sufficient to remove organic contents. From the gas sensing response measurements for various NO gas concentrations in dry air at several working temperatures, it was found that gas sensors based on electrospun ZnO nanofibers showed quite good responses, exhibiting a maximum sensitivity to NO gas in dry air at an operating temperature of 200˚C. In particular, the non-directional electrospun ZnO nanofiber gas sensors were found to have a good NO gas detection limit of sub-ppm levels in dry air. These results illustrate that non-directional electrospun ZnO nanofibers are promising for use in low-cost, high-performance practical NO gas sensors.

Metal nanowires can be coated on various substrates to create transparent conducting films that can potentially replace the dominant transparent conductor, indium tin oxide, in displays, solar cells, organic light-emitting diodes, and electrochromic windows. One issue with these metal nanowire based transparent conductive films is that the resistance between the nanowires is still high because of their low aspect ratio. Here, we demonstrate high-performance transparent conductive films with silver nanofiber networks synthesized by a low-cost and scalable electrospinning process followed by two-step sequential thermal treatments. First, the PVP/AgNO3 precursor nanofibers, which have an average diameter of 208 nm and are several thousands of micrometers in length, were synthesized by the electrospinning process. The thermal behavior and the phase and morphology evolution in the thermal treatment processes were systematically investigated to determine the thermal treatment atmosphere and temperature. PVP/AgNO3 nanofibers were transformed stepwise into PVP/Ag and Ag nanofibers by two-step sequential thermal treatments (i.e., 150˚C in H2 for 0.5 h and 300˚C in Ar for 3 h); however, the fibrous shape was perfectly maintained. The silver nanofibers have ultrahigh aspect ratios of up to 10000 and a small average diameter of 142 nm; they also have fused crossing points with ultra-low junction resistances, which result in high transmittance at low sheet resistance.

nanotubes were successfully synthesized using an electrospinning technique followed by calcination in air. The nanotubes were the single phase nature of and consisted of approximately 14 nm nanocrystals. SEM and TEM characterizations demonstrated that uniform hollow fibers with an average outer diameter of around 124 nm and wall thickness of around 25 nm were successfully obtained. As anode materials for lithium ion batteries, the nanotubes exhibited excellent cyclability and reversible capacity of up to 25 cycles at as compared to nanoparticles with a capacity of . Such excellent performance of the nanotube was related to the one-dimensional hollow structure which acted as a buffer zone during the volume contraction and expansion of Sn.

Functional nanomaterial is expected to have improved capacities on various fields. Especially, metal nanoparticles dispersed in polymer matrix and metal nanofiber, one of the functional nanomaterials, are able to achieve improvement of property in the electric and other related fields. In this study, the fabrication of metal (Ag) nanoparticle dispersed nanofibers were attempted. The Ag nanoparticle dispersed polymer nanofiber and Ag nanofiber were fabricated by electrospinning method using electric force. First, PVP/ nanofibers were synthesized by electrospinning in voltage with the starting materials (Ag-nitrate) added polymer (PVP; poly (vinylpyrrolidone)). Then Ag nanoparticle dispersed polymer nanofibers were fabricated to reduce hydrogen reduction at for 3hr. And Ag nanofibers were synthesized by the decomposited of PVP at for 3hr. The nanofibers were analyzed by XRD, TGA, FE-SEM and TEM. The experimental results showed that the Ag nanofibers could be applied in many fields as an advanced material.

Polyethersulfone (PES)와 Bovine Serum Albumin (BSA) 용액으로 전기방사법을 이용하여 단백질 친화막을 제조하였다. 방사운전조건(방사용액의 농도, 전압, 방사속도, 방사거리)을 다양하게 조절하여 나노섬유의 크기를 관찰하였으며, 최적의 친화막 제조 조건을 확인할 수 있었다. XPS와 FT-IR로써 PES와 BSA의 결합을 확인하였으며, PES-BSA 나노섬유의 최적 방사 온도와 습도는 20~22℃와 45~55% 임을 알 수 있었다. 또한 PES 함량이 증가할수록 섬유의 크기가 증가하고, BSA의 경우 나노섬유의 크기에 큰 영향이 없음을 알았다. PES 7 wt%, BSA 0.7 wt%. Hexafluropropanol (HFP) 92.3 wt%의 용액을 이용하여 전압 10.0 kV, 방사거리 10 cm, 방사속도 1.0 mL/hr의 조건에서 방사한 경우 균일한 크기의 PES-BSA 나노섬유가 얻어졌다.

Ethyl (4-(2,3-dihydro- 1H-indene-5-carboxyamido) benzoate)는 노화방지 효과가 있으나 난 용성 및 결정화 특성을 가지고 있어 제형화 및 2차 가공을 통해 입자내 활성성분을 담지시키는데 어려움이 있으 며, 3,5,7-trihydroxy-4’-methoxy-8-prenylflavone는 플라보노이드(flavonoid)류의 일종으로 미백기능 을 가지고 있으나 복합제형에 사용할 경우 제형의 착색을 일으키는 물질 중 하나이다. 본 연구에서는 전기방사법 을 이용하여 유용성/난용성 생리활성성분인 ethyl (4-(2,3-dihydro-1H-indene-5-carboxyamido) benzoate) 와 3,5,7-trihydroxy-4’-methoxy-8-prenylflavone 성분을 각각 poly (methyl methacrylate)와 polycaprolactone 고분자 입자 내에 담지 시키고 이를 화장품 제형에 적용했을 때 나타나는 효과에 대해서 기술 하였다. 입자내 활성성분을 담지시킨 고분자 입자를 제조하는 과정에는 고분자의 농도, 노즐의 구조, 그리고 고 분자와 생리활성 성분의 상용성이 중요한 역할을 하였다. 아울러 3,5,7-trihydroxy-4’-methoxy-8-prenylflavone가 캡슐화된 polycaprolactone 고분자 입자를 금속산화물이 포함된 화장품 제형과 혼합하였을 경우, 고분자 입자는 캡슐화 되지 않은 flavonoid가 제형에 포함되었을 경우 나타나는 착색현상을 방지하는 데 효과적 일 수 있다는 결과를 확인하였다.