• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.738-742
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• 2012

Here, we develop a new nanofilter device for the rapid and efficient separation of nanoparticles and biomolecules, exploiting the use of AAO mebrane with ordered nanopores in the range from 20 nm to 200 nm. Briefly, the chip comprises of a series of the upper and lower PDMS channels containing embedded inlet and outlet ports, and $50{\mu}m$ width microfluidic channel, and AAO membrane to be made the filtering zone. After assembling these components, the acrylate plastic plates were used to fix the device on the top and bottom side. When introducing the samples into the inlet ports of the upper PDMS channel, we were able to separate and concentrate the nanoparticles and target molecules at the filtering zone, and to elute the solutions containing the unwanted materials toward the lower PDMS channels normal to the direction of AAO membrane. To demonstrate the usefulness of the device we apply it to the SERS detection of nucleic acid sequences associated with Dengue virus serotype 2. We report a limit of detection for Dengue sequences of 300 nM and show excellent enhancement of Raman signals from the filter zone of the nanofilter device.

• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.191-196
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• 2017

One-phase method to prevent the initial formation of Ag(I) thiolate layered materal from the mixture of $AgNO_3$ and thiols was previously developed to generate TP (Thiolate-Protected)-nanosilver. In this modified method, $AgNO_3$ is added to the mixtures of $NaBH_4$ and thiols in ethanol. This method was so successful that it was applied to synthesize TP-nanogold and nanoplatinum. The synthesis and characterization of these nanoparticles by ultraviolet-visible (UV-vis) absorption spectra, transmission electron microscopy (TEM) pictures, X-ray powder differaction (XRD) patterns and infrared(IR) spectra are described. The results show that colloidal nanoparticles are spherical or oval shape and the mean sizes for TP-nanogold and nanoplatinum are about 3~7 nm and below 2 nm, respectively. The conformation of polymethylene [$-(CH_2)_7-$] sequence in octanethiolate attached to nanogold was elucidated as trans.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.170-176
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• 2006

A spark discharge aerosol generator using air as a carrier gas has successfully been applied to silver nanoparticle production. The spark discharge between two silver electrodes, which was periodically obtained by discharging the capacitor, produced sufficient high temperatures to evaporate a small fraction of the silver electrodes. The silver vapor was subsequently supersaturated by rapid cooling and condensed to silver nanoparticles by nucleation and condensation. The morphology of the generated particles observed by transmission electron microscope was spherical. The element composition of the nanoparticles was silver, which was determined by energy dispersive X-ray spectroscopy. The crystal phase of the particles spark-generated under air atmosphere was composed of silver and silver oxides phase, which was determined by Xray diffraction analysis. While the nanoparticles generated under nitrogen atmosphere had only silver phase. This XRD data indicates that some fraction of the evaporated silver vapor could be oxidized in air atmosphere by the reaction with oxygen. A stable operation of the spark discharge generator has been achieved. The size and concentration of the particles can be easily controlled by altering the repetition frequency, capacitance, gap distance and flow rate of the spark discharge system.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.56-56
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• 2011

알코올 환원법(alcohol reducing process)은 화학적 환원제가 필요하지 않은 화학합성법으로 메탄올, 에탄올, 프로판올, 이소프로판올, 부탄올 등 C1-C4의 알코올류, 에틸렌 글라이콜, 디에틸렌 글라이콜, 프로필렌 글라이콜과 같은 글리콜류 등이 용매이자 환원제로써 사용된다. 전형적으로 금속 전구체를 상기의 알코올류나 글리콜류에 용해 또는 분산시킨 후 그 용액을 환류 조건하에서 가열하게 되면 금속 이온과 용매간의 산화, 환원반응에 의하여 금속이온이 금속원자로 환원되며, 환원된 금속 입자들은 핵 행성과 성장 과정을 거쳐서 입자를 형성하게 된다. 본 연구에서는 알코올환원법을 이용하여 나노크기의 은입자제조를 시도하였고, 이를 PET 칩과의 마스터배치 제조을 시도하였으며, 이의 항균성능을 연구 고찰하였다. 30 ~ 80 nm의 은파우더를 제조할 수 있었으며, 우수한 항균성능을 갖는 Ag/PET 마스터배치를 제조할 수 있었다. 이를 활용하여 나노은입자기반의 항균섬유을 제조하여 이를 활용한 기모경편성물 제조의 기초데이타로 활용이 가능하리라고 사료된다.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1100-1105
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• 2020

We investigated the driving force and the required charges for spontaneous reduction of metal nanoparticles (NPs) on a scotch tape induced by mechanochemical activation. The charges were analyzed based on anodic stripping voltammetry (ASV) of silver, which is proportional to the number of charge identities on the tape. The results supported that the driving force is mechanochemical radicals rather than ions in the light of the high charge density on the tape.

• Polymer(Korea)
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• v.36 no.5
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• pp.586-592
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• 2012

Iron oxides ($Fe_3O_4$) are metabolically secreted after endocytosed by cells, indicating no cytotoxicity. Therefore, they are widely used as a contrast agent before photographing of magnetic resonance imaging. In this study, iron oxide nanoparticles are synthesized by the co-precipitation method and subsequently immobilized with a homing peptide (AP), which specifically interacts with interleukin-4 receptor located on the membrane of endothelial and bladder cancer cells. The size of AP-immobilized iron oxide particle is about 39 nm. Intracellular uptake of the AP-immobilized iron oxide nanoparticles was investigated using bladder cancer cells and fibroblasts as the control. As the result, the nanoparticles are specificially uptaken by bladder cancer cells. However, the nanoparticles are not specificially uptaken by fibroblast. It could be said that the AP-immobilized iron oxide nanoparticles have a potential to be used as a contrast agent for early diagnosis of cancer.

• Composites Research
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• v.36 no.4
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• pp.275-280
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• 2023

Because polymer-based composites are lightweight and have excellent properties, their demand is growing rapidly as a way to fulfill properties that are difficult to achieve with a single material. As a result, there has been a lot of research on polymer nanocomposites, which are made by dispersing particles with a size of 1-100 nm in a polymer matrix. In addition, many nanocomposites using thermoplastic resins as matrix materials are being studied. In this study, poly(ethylene terephthalate) (PET)-based nanocomposites containing organic nanoclays modified with cetyltrimethylammonium bromide (CTAB) as interlayer materials were prepared. Among various nanoclays, vermiculite (VMT) has been studied to increase the mechanical and thermal properties of polymeric materials due to its low cost, abundant reserves and unique properties. However, the strong interlayer bonding of VMT has limited its utilization due to its poor exfoliation and dispersion performance within polymer matrices. In this study, the mechanical properties of the VMT content were confirmed by tensile tests, the dispersion of VMT particles in the PET matrix was evaluated by TEM cross-sectional images, and the nitrogen gas barrier properties were evaluated.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.475-476
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• 2007

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.345-349
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• 2008

• Particle and aerosol research
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• v.6 no.3
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• pp.107-121
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• 2010

The number of nanotechnology based consumer products are growing rapidly. Thus, the customer likely to be exposed to such products continues to increase as the applications expand. This article describes the international and Korea's policies on the EHS(Environment, Safety and Health) issues of nanotechnologies. The strategic plan and coordination of OECD and ISO were summarized. This article also examines several new findings of Korean researchers as well as current and future challenges in the aerosol application study of EHS issues on the nanotechnologies.