Swelling Behavior and Drug Release of Poly(vinyl alcohol) Hydrogel Cross-Linked with Poly(acrylic acid)

Hongsik Byun,Byungpyo Hong,Sang Yong Nam,Sun Young Jung,Ji Won Rbim,Sang Bong Lee,Go Young Moon 한국고분자학회 2008 Macromolecular Research Vol.16 No.3

Polymer particles filled with multiple colloidal silica via <i>in situ</i> sol-gel process and their thermal property

Byun, Hongsik,Hu, Jiayun,Pakawanit, Phakkhananan,Srisombat, Laongnuan,Kim, Jun-Hyun IOP 2017 Nanotechnology Vol.28 No.2

<P>The <I>in situ</I> formation of dielectric silica (SiO<SUB>2</SUB>) particles was carried out in the presence of temperature-responsive poly(<I>N</I>-isopropylacrylamide) particles. Unlike the typical sol-gel method used to prepare various SiO<SUB>2</SUB> particles, the highly uniform growth of SiO<SUB>2</SUB> particles was achieved within the cross-linked polymer particles (i.e., the polymer particles were filled with the SiO<SUB>2</SUB> particles) simply by utilizing interfacial interactions, including the van der Waals attractive force and hydrogen bonding in nanoscale environments. The structural and morphological features as well as the thermal behaviors of these composites were thoroughly examined by electron microscopes, dynamic light scattering, and thermal analyzers. In particular, the thermal properties of these composites were completely different from the bare polymer, SiO<SUB>2</SUB> particles, and their mixtures, which clearly suggested the successful incorporation of multiple SiO<SUB>2</SUB> particles within the cross-linked polymer particles. Similarly, titanium oxide (TiO<SUB>2</SUB>) particles were easily embedded within the polymer particle template which exhibited improved overall properties. As a whole, understanding <I>in situ</I> formation of nanoscale inorganic particles within polymer particle templates can allow for designing novel composite materials possessing enhanced chemical and physical properties.</P>

Membrane Morphology: Phase Inversion to Electrospinning

N. Chanunpanich,Hongsik Byun,Inn-Kyu Kang 한국막학회 2005 멤브레인 Vol.15 No.2

Recently, membrane can be prepared by two methods, phase inversion and electrospinning techniques. Phase inversion technique is a conventional but commercially preparation membrane. The most versatile of preparation in this technique is immersion of the cast film into nonsolvent bath, causing dense top layer with a finger-like pattern in the sub layer membrane. The membrane pore size getting from phase inversion is in the range of micro or submicrometer. As a result, it can be used as microfiltration and ultrafiltration applications. A new technique, electrospinning, is introduced for membrane preparation. Nonwoven nanofibrous mat or nanofibrous membrane is obtained. In this technique, electrostatic charge is introduced to the solution jet, causing a thin fiber with high surface area; hence it can be used in the applications where high surface area-to-volume or length-to-diameter ratios are required. Moreover, the pore size can be controlled by controlling the time of electrospinning. Hence, it can be used as a filter for filtering microparticles as well as nanoparticles.

The Current Membrane Industrial Situation in China and Introduction of “China Membrane Valley”

Jian Hou,Hongsik Byun,Sungil Jeon 한국막학회 2020 한국막학회 총회 및 학술발표회 Vol.2020 No.11

Membrane Morphology: Phase Inversion to Electrospinning

Chanunpanich N.,Byun Hongsik,Kang Inn-Kyu The Membrane Society of Korea 2005 멤브레인 Vol.15 No.2

Recently, membrane can be prepared by two methods, phase inversion and electrospinning techniques. Phase inversion technique is a conventional but commercially preparation membrane. The most versatile of preparation in this technique is immersion of the cast film into nonsolvent bath, causing dense top layer with a finger-like pattern in the sub layer membrane. The membrane pore size getting from phase inversion is in the range of micro or submicrometer. As a result, it can be used as microfiltration and ultrafiltration applications. A new technique, electrospinning, is introduced for membrane preparation. Nonwoven nanofibrous mat or nanofibrous membrane is obtained. In this technique, electrostatic charge is introduced to the solution jet, causing a thin fiber with high surface area; hence it can be used in the applications where high surface area-to-volume or length-to-diameter ratios are required. Moreover, the pore size can be controlled by controlling the time of electrospinning. Hence, it can be used as a filter for filtering microparticles as well as nanoparticles.

Preparation of electrospun polyketone membranes

Chanju Park,Hongsik Byun 한국막학회 2020 한국막학회 총회 및 학술발표회 Vol.2020 No.11

A simple template-free ‘sputtering deposition and selective etching’ process for nanoporous thin films and its application to dye-sensitized solar cells

Nahm, Changwoo,Choi, Hongsik,Kim, Jongmin,Byun, Sujin,Kang, Suji,Hwang, Taehyun,Hejin Park, Helen,Ko, Jaejung,Park, Byungwoo IOP Pub 2013 Nanotechnology Vol.24 No.36

<P>A facile and straightforward method is suggested to synthesize nanoporous-TiO<SUB>2</SUB> thin films for dye-sensitized solar cells (DSSCs). Silver/TiO<SUB>2</SUB> co-sputtering led to the formation of nanocomposite films which consisted of silver nanoclusters with surrounding TiO<SUB>2</SUB> matrices, and metal particles were subsequently etched by just immersing in nitric acid. Nanoporous-TiO<SUB>2</SUB> DSSCs fabricated by this simple and effective process showed power-conversion efficiencies of up to 3.4% at a thickness of only 1.8 μm, which is much superior to that of conventional nanoparticulate-TiO<SUB>2</SUB> DSSCs with similar thickness.</P>

전기방사법을 이용한 PVdF/Fe3O4-GO(MGO) 복합 분리막 제조 및 비소 제거 특성평가

Wongi Jang,Jian Hou,Hongsik Byun,Jae Yong Lee 한국막학회 2016 멤브레인 Vol.26 No.6

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. In this study, the PVdF/MGO composite nanofiber membranes (PMGs) introducing Iron oxide-Graphene oxide (Fe3O4/GO, Metallic graphene oxide; MGO) was prepared via electrospinng method and its arsenic removal characteristics were investigated. The thermal treatment was carried out to improve the mechanical strength of nanofiber membranes and then the results showed that of outstanding improvement effect. However, in case of PMGs, the decreasing tendency of mechanical strength was indicated as increasing MGO contents. From the results of pore-size analysis, it was confirmed that the porous structured membranes with 0.3 to 0.45 μm were prepared. For the water treatment application, the water flux measurement was carried out. In particular, PMG2.0 sample showed about 70% improved water flux results (153 kg/m2h) compared to that of pure PVdF nanofiber membrane (91 kg/m2h) under the 0.3 bar condition. In addition, the PMGs have indicated the high removal rates of both As(III) and As(V) (up to 81% and 68%, respectively). Based on the adsorption isotherm analysis, the adsorption of As(III) and As(V) ions were both more suitable for the Freundlich. From all of results, it was concluded that PVdF/MGO composite nanofiber membranes could be utilized as a water treatment membrane and for the Arsenic removal applications.

Preparation of polyvinylidene fluoride nanofiber membrane and its antibacterial characteristics with nanosilver or graphene oxide.

Hong, Byungpyo,Jung, Hyemin,Byun, Hongsik American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.9

<P>Polyvinylidene fluoride (PVdF) (Kynar 761) nanofibers were prepared by electrospinning at an external voltage of 6-10 kV, a traveling distance of 7-15 cm and flow rate of 0.4-1 ml/hr. Although the diameter of the fiber was not significantly changed, the electrospinning conditions affected the overall distribution of diameter. This is probably due to the interactions, both attraction and repulsion, of positive charges on polymer solutions and the electrically grounded collector. Especially, the effect of voltage on the distribution of diameter was investigated in this study. The final PVdF nanofiber membrane showed narrow pore-size distribution and high water flux compared with the commercial MF membrane. PVdF nanofiber membranes incorporated nanosilver or graphene oxide were also prepared as nanosilver and graphene have an antibacterial activity. It was found that more than 200 ppm of silver nanoparticles in the PVdF nanofiber had 99.9% of growth inhibition of Staphylococcus aureus and Klebsiella pneumonia. It was also found that 0.2 wt% of graphene oxide in the PVdF electrospinning solution had 99.6% of disinfection property to E-Coli.</P>

리튬이차전지 전해액의 고온 안정성을 위한 PVA-CN 첨가제 합성 및 평가

후건(Jian Hou),장원기(Wongi Jang),변홍식(Hongsik Byun) 한국고분자학회 2018 폴리머 Vol.42 No.5

현재 리튬이차전지에는 이온전도도나 전기화학적 안정성이 좋은 액체 전해액을 사용하고 있으나, 고온 열적 안정성에 문제가 노출되고 있다. 본 연구에서는 전해액의 열 안정성을 향상시키기 위해 리튬이차전지 전해액용 cyanoethyl polyvinyl alcohol(PVA-CN) 첨가제를 합성하였으며, 합성은 polyvinyl alcohol(PVA) 원료를 용해하는 공정(Step 1)과 PVA-CN을 합성하는 공정(Step 2)으로 나누어서 진행하였다. 합성된 PVA-CN 첨가제의 열적 안정성을 확인하기 위하여 TGA 측정을 진행하였다. 전기적 특성평가에서 PVA-CN이 첨가된 전해액의 이온전도도가 기존 상용의 전해액보다 약 6% 감소하였다. 하지만, PVA-CN 첨가된 전해액을 활용한 리튬이차전지는 고온에서 swelling 특성이 매우 우수한 결과, 즉 29%의 swelling 감소 효과를 보여주었으며, 리튬이차전지의 가장 큰 사고 원인인 고온 swelling 문제를 해결할 수 있다는 결과를 얻었다. Currently liquid electrolyte having good ion-conductivity and high electrochemical stability has been used for the lithium secondary battery. But it has been reported there was a serious problem in the high temperature stability. In this study, the development of PVA-CN cyanoethyl polyvinyl alcohol additive which is used in lithium secondary battery electrolyte was carried out with two steps; the first step was the dissolution of PVA raw materials, and the second step was the synthesis of PVA-CN. The thermal property of the prepared PVA-CN was quantitatively analyzed using TGA. The significantly improved thermal stability of the electrolytes containing PVA-CN additives was also confirmed by monitoring swelling behavior of the membranes at high temperature, i.e. 29% less swelling effect, although they exhibited slightly lower ion conductivity, about 6% lower than commercially available electrolytes. This finding clearly suggests the possibility of preventing the swelling issue at high temperature which is the main cause of dangerous accidents from secondary battery systems.