• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.68-73
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• 2017

The removal of particulate matter ranging from $0.01{\mu}m{\sim}10{\mu}m$ can be performed by using membrane filters composed of fibers. Electrospinning techniques offer the production of very thin fibers with a uniform fiber diameter over conventional techniques including template synthesis, melt-blown, phase separation, etc. Air filtration will be improved with electrospun membranes due to the open pore structures, high porosity, and large surface area of the membranes. In the present study, filtration efficiency increased with pore size decrease and fiber density increase induced by carbon nanotube and the increased CA (cellulose acetate) concentration during electrospinning process.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.41.2-41.2
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• 2009

Electrospinning of Polyvinylalcohol (PVA), Gelatin (GE), and PVA/GE blend solutions in acetic acid were investigated to fabricate biodegradable for tissue engineering. The morphology of the electrospun nanofibers was investigated with a field emission scanning electron microscope. The fibers have average diameters in the range 50-150 nm. The miscibility of PVA/GE blend fibers was examined by differential scanning calorimetry.The PVA and GE were immiscible in the as-spun nanofibrous structure. X-ray diffraction (XRD) determined the crystallinity of the membrane and tensile strength for evaluation physical properties. An in vitro study of PVA/GE blend nanofibers was conducted. To assay the cytocompatibility and cell behavior on the PVA/GE blend nanofibrous scaffolds, cell attachment and spreading of fibroblasts seeded on the scaffolds were studied. Our results indicate that thePVA/GE blend nanofibrous matrix, particularly the one that contained 20% PVA and 80% GE could be a good candidate for tissue engineering scaffolds, because it has an excellent cell attachment and spreading for fibroblast cell.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.51.2-51.2
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• 2011

A novel electrospun nanofiber membrane was fabricated using combined poly (vinylphosphonic acid) (PVPA) and polyvinyl alcohol (PVA) intended for bone tissue engineering applications. PVPA is a proton-conducting polymer used as primer for bone implants and dental cements to prevent corrosion and brush abrasion. The phosphonate groups of PVPA have the ability to crosslink and attach itself to the hydroxyapatite surface facilitating faster integration of the biomaterial to the bone matrix. PVA was combined with PVPA to provide hydrophilicity, biocompatibility and improve its spinnability. To improve its mechanical strength, PVPA/PVA and neat PVA mixtures were combined to produce a multilayer scaffold. The physical and chemical properties of the of the fabricated matrix was investigated by SEM and TEM morphological analyses, tensile strength test, XRD, FT-IR spectra, swelling behavior and biodegradation rates, porosity and contact angle measurements. Biocompatibility was also examined in vitro by cytotoxicity and cell proliferation studies with MTT assay and cell adhesion behavior by SEM and confocal microscopy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.2
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• pp.21-27
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• 2014

Recently, various biochip environments have been presented. In this study, a novel transparent film with porous membrane windows, which is an essential component in a co-cultured biochip environment, is fabricated using spin-coating, 3D printing, and electrospinning processes. In detail, a transparent polystyrene film was fabricated by means of the spin-coating process followed bywindow cutting, after which apolycaprolactone-chloroform solution was deposited along the window edge to introduce an adhesion layer between the PS film and the PCL nanofibers. Nanofibers were electrospun into the window region using a direct-write electrospinning method. Consequently, it was demonstrated that the fabricated window film could be used in a co-culture biochip environment.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.229.1-229.1
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• 2003

Recently, the barrier membranes have been applied for regenerating bone surrounding peri-implant defects in guided bone regeneration(GBR). GBR membrane should provide mechanical support sufficient to withstand in vivo forces and maintain wound space for bone regeneration. The ability to exclude unwanted tissues of cells(connective tissue and epithelium) is needed. In addition large surface area is conductive to tissue ingrowth. The search for ideal materials that biocompatible, bioresorbable and can support the growth and phenotypic expression of osteoblasts is a major challenge in the biomedical application for the repair of bone defects. (omitted)

• Membrane Journal
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• v.29 no.3
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• pp.123-129
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• 2019

Environmental pollution caused by the presence of heavy metal ion from growing industrialization or from leaching is increasing area of concern. There are several area of water purifications but among them adsorption on the functionalized polymer fibers is efficient and cost-effective method. Polyacrylonitrile (PAN) is exciting polymer due to the presence of excessive functional group which can be easily transformed for metal ion adsorption. PAN can be easily electrospun to prepare nanofiber that have higher surface area leading to better metal ion removal. Composite PAN fiber is yet another type of polymer covered in this review for waste water treatment.

• Membrane Journal
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• v.33 no.2
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• pp.70-76
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• 2023

Heavy water (D₂O) can induce various biochemical changes in comparison with light water (H₂O). In order to reduce excessive energy consumption, which is a disadvantage of the existing separation process, we conduct the forward osmosis with electrospun polyamide membranes. NaCl and phosphoric acid were used as draw solutions. FT-IR spectroscopy was used to quantify the concentration of heavy water. It was observed that phosphoric acid could concentrate heavy water through a forward osmosis process and its special interaction with hydrogen/deuterium (H/D) was spectrophotometrically confirmed.

• Macromolecular Research
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• v.16 no.3
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• pp.212-217
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• 2008

PVDF ($Kynar^{(R)}$ 761) nanofibers were made by electrospinning with an external voltage of 6-10 kV, a traveling distance of 7-15 cm and a flow rate of 0.4-1 mL/h. Although the mean diameter of the fibers has not changed significantly, the conditions affected the change in diameter distribution. This was attributed to interactions, both attraction and repulsion, between the positive charges on the polymer solutions and the electrically grounded collector. Higher voltages and traveling distance increased the level of attraction between the positive charge on the polymer solution and the electrically grounded collector, resulting in a narrow diameter distribution, In addition, a high flow rate allowed a high population of uniformly charged solutions to travel to the grounded collector, which resulted in a narrow diameter distribution. The optimum conditions for electrospinning of PVDF in DMAc/acetone (3/7 by wt) were a collector voltage of 6 kV, a syringe tip to collector of 7 cm, a flux rate of 0.4 mL/h and 10 kV, 10 cm, 1 mL/h, Since PVDF is widely used as a filtration membrane, it was electrospun on a PET support with a rotating drum as a grounded collector. Surprisingly, some straight nanofibers were separated from the randomly deposited nanofibers. The straight nanofiber area was transparent, while the randomly deposited nanofiber area was opaque. Both straight nanofibers and aligned nanotibers could be obtained by manipulating the PET drum collector. These phenomena were not observed when the support was changed to an Al sheet. This suggests that a pseudo dual collector was generated on the PET sheet. No negative charge was created because the PET sheet was not a conductive material. However, less charge was created when the sheet was not perfectly attached to the metal drum. Hence, the nanotibers jumped from one grounded site to the nearest one, yielding a straight nanofiber.

• Journal of Electrochemical Science and Technology
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• v.6 no.1
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• pp.26-33
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• 2015

In this study, cell performance and thermal stability of lithium-ion cells with a polyimide (PI) separator are investigated. In comparison to conventional polyethylene (PE) separator, the PI separator exhibits distinct advantage in microporous structure, leading to superior reliability of the cell. The cells with PI separator exhibit good cell performances as same as the cells with PE separator, but their reliability was superior to the cell with PE separator. Especially in the hot-box test at 150 and 180℃, PI separator showed a contraction percentage close to 0% at 150℃, while the PE separator showed a contraction percentage greater than 10% in both width and length. Therefore, the PI separator can be the promising candidate for separators of the next generation of lithium-ion battery.

• Macromolecular Research
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• v.16 no.3
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• pp.204-211
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• 2008

A platinum-catalyzed polyelectrolyte porous membrane was prepared by solid-state compression of electrospun polystyrene (PS) fibers and in-situ metallization of counter-balanced ionic metal sources on the polymer surface. Using this ion-exchange metal-polymer composite system, fiber entangled pores were formed in the interstitial space of the fibers, which were surrounded by sulfonic acid sites ($SO_3^-$) to give a cation-selective polyelectrolyte porous bed with an ion exchange capacity ($I_{EC}$) of 3.0 meq/g and an ionic conductivity of 0.09 S/cm. The Pt loading was estimated to be 16.32 wt% from the $SO_3^-$ ions on the surface of the sulfonated PS fibers, which interact with the cationic platinum complex, $Pt(NH_3)_4^{2+}$, at a ratio of 3:1 based on steric hindrance and the arrangement of interacting ions. This is in good agreement with the Pt loading of 15.82 wt% measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The Pt-loaded sulfonated PS media showed an ionic conductivity of 0.32 S/cm. The in-situ metallized platinum provided a nano-sized and strongly-bound catalyst in robust porous media, which highlights its potential use in various electrochemical and catalytic systems.