이전 연구에서 올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparicles (AgNPs)(전구체AgBF4)/pbenzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지 되는 것이 확인되었다. 하지만 전구체인 AgBF4의 가격이 고가이기 때문에, 본 연구에서는 가격 측면에서 경쟁력이 있는 AgNO3를 Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과 이미 존재하고 있는 NO3 -가 AgNPs를 감싸고 있기 때문에 분리 성능이 나오지 않는 것으로 관찰되었다. 이번 연구에서는 AgNO3를 Ag nanoparticles의 전구체로 사용하여도 높은 성능을 내기 위해 전자수용체 7,7,8,8-tetracyanoquinodimethane (TCNQ)를 사용하여 PEO, polyvinyl alcohol (PVA), polyether block amide-1657 (PEBAX-1657) 고분자 복합막을 제조한 결과, 고분자와 전자수용체의 영향과는 무관하게 분리 성능을 내지 못하는 것으로 분석되었으며, 이는 분리성능에 전구체의 음이온이 결정적 역할을 하는 것으로 분석되었다.

An imprinted potentiometric sensor was developed for direct and selective determination of gabapentin. Sensor is based on carbon paste electrode adapted by graphene oxide that is decorated with silver nanoparticles and mixed with molecularly imprinted polymers nanoparticles using gabapentin as a template molecule. The synthesized nanoparticles were characterized by Fourier transmission infrared spectroscopy, transmission electron microscopy and X-ray diffraction. Under optimal experimental conditions, the studied sensor exhibited high selectivity and sensitivity with LOD of 4.8×10–11 mol L–1. It provided a wide linearity range from 1×10–10 to 1×10–3 mol L–1and high stability for more than 3 mo. The sensor was effectively used for the determination of gabapentin in pharmaceutical tablets and spiked plasma samples.

We perform density functional theory calculations to study the CO and O2 adsorption chemistry of Pt@X core@shell bimetallic nanoparticles (X = Pd, Rh, Ru, Au, or Ag). To prevent CO-poisoning of Pt nanoparticles, we introduce a Pt@X core-shell nanoparticle model that is composed of exposed surface sites of Pt and facets of X alloying element. We find that Pt@Pd, Pt@Rh, Pt@Ru, and Pt@Ag nanoparticles spatially bind CO and O2, separately, on Pt and X, respectively. Particularly, Pt@Ag nanoparticles show the most well-balanced CO and O2 binding energy values, which are required for facile CO oxidation. On the other hand, the O2 binding energies of Pt@Pd, Pt@Ru, and Pt@Rh nanoparticles are too strong to catalyze further CO oxidation because of the strong oxygen affinity of Pd, Ru, and Rh. The Au shell of Pt@Au nanoparticles preferentially bond CO rather than O2. From a catalysis design perspective, we believe that Pt@Ag is a better-performing Ptbased CO-tolerant CO oxidation catalyst.

The coupling of two semiconducting materials is an efficient method to improve photocatalytic activity via the suppression of recombination of electron-hole pairs. In particular, the coupling between two different phases of TiO2, i.e., anatase and rutile, is particularly attractive for photocatalytic activity improvement of rutile TiO2 because these coupled TiO2 powders can retain the benefits of TiO2, one of the best photocatalysts. In this study, anatase TiO2 nanoparticles are synthesized and coupled on the surface of rutile TiO2 powders using a microemulsion method and heat treatment. Triton X-100, as a surfactant, is used to suppress the aggregation of anatase TiO2 nanoparticles and disperse anatase TiO2 nanoparticles uniformly on the surface of rutile TiO2 powders. Rutile TiO2 powders coupled with anatase TiO2 nanoparticles are successfully prepared. Additionally, we compare the photocatalytic activity of these rutile-anatase coupled TiO2 powders under ultraviolet (UV) light and demonstrate that the reason for the improvement of photocatalytic activity is microstructural.

In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M HNO3, a reaction temperature of 75℃, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, NaBH4 and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

Cost-effective functional phosphor nanoparticles are prepared by introducing low-cost SiO2 spheres to rareearth phosphor (YVO4:Eu3+, YVO4:Er3+, and YVO4:Nd3+) shells using a sol-gel synthetic method. These functional nanoparticles are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and general photoluminescence spectra. The SiO2 sphere occupying the interior of the conventional phosphor is advantageous in significantly reducing the cost of expensive rare-earth phosphor nanoparticles. The sol-gel process facilitates the core–shell structure formation; the rare-earth shell phosphor has strong interactions with chelating agents on the surfaces of SiO2 nanoparticles and thus forms layers of several nanometers in thickness. The photoluminescence wavelength is simply tuned by replacing the active materials of Eu3+, Er3+, and Nd3+. Moreover, the photoluminescent properties of the core–shell nanoparticles can be optimized by manipulating the specific contents of active materials in the phosphors. Our simple approach substitutes low-cost SiO2 for expensive rare-earth-based phosphor materials to realize cost-effective phosphor nanoparticles for various applications.

The demand for energy storage devices capable of operating at high temperatures is increasing. In order to operate at high temperatures, a device must have excellent thermal stability and no risk of explosion. Ionic liquids are electrolytes that satisfy the above conditions, and studies on improving their performance have attracted great interest. Here, we report the results of a study on the fabrication of a supercapacitor that has a composite electrolyte prepared by dispersing fumed silica in an ionic liquid. The fumed silica filler exhibits improved ionic conductivity and lower interfacial resistance. In particular, the silica nanoparticles with diameters of 10 nm exhibit better electrochemical properties than fillers of other diameters and have excellent device performance of 33 times higher than the pristine ionic liquid at high temperatures. This study can be used to improve the electrolytes of electrochemical devices, such as the next generation battery or lithium ion battery.

본 연구에서는 CeO2 표면에 Ti(SO4)2의 가수 분해를 이용하여 TiO2를 성장시켜 코어-쉘 구조를 가지는 세라믹 나노입자를 합성 하였다. CeO2/TiO2 코어-쉘 합성에서는 CeO2:TiO2의 몰비, 반응 시간, 반응 온도, CeO2 슬러리 농도, Ti(SO4)2의 pH 조절을 통하여 코어-쉘 구조를 가지는 최적의 합성 조건을 찾았다. CeO2:TiO2의 최적의 몰비는 1:0.2~1.1, 최적의 반응 시간은 24 시간, 최적의 CeO2 슬러리 농도는 1%, 최적의 반응 온도는 50℃임을 알 수 있었다. NH4OH 수용액을 이용하여 Ti(SO4)2 의 pH를 1로 맞추어 CeO2 슬러리에 적하하면 10%의 농도를 가지는 CeO2 슬러리에서도 CeO2/TiO2 코어-쉘 나노 입자를 합성할 수 있었다. 80℃이상의 높은 온도에서 반응을 시키면 CeO2/TiO2 코어-쉘 구조가 아닌 독립된 TiO2 나노 입자를 형성함을 알 수 있었다. 최적의 반응 온도는 50℃로서 가장 좋은 구조의 CeO2/TiO2 코어-쉘이 합성되었다.

본 연구에서는 수용성 도료의 내후성 및 내광성을 향상 시키고 광택도 및 비극성수지와의 결합을 조절하기 위해 수용성 도료와 표면 개질된 금속 산화물 나노입자를 혼합하여 물성 변화 특성을 연구하였다. SiO2, TiO2를 실란커플링 제로 표면개질 하여 수용성 도료에 혼합하였으며, 볼밀을 이용하여 금속산화물 나노입자를 수용성 도료에 분산 시켰다. (3-Glycidoxypropyl) trimethoxysilane (GPS)로 표면 개질된 금속 산화물 나노입자를 VOC(Volatile Organic Compounds), 저장 안정성 평가 및 광택을 측정하였다.

최근, 실리카는 코팅제 및 복합체의 충전제로 많이 사용되고 있으며 상용성을 증가시키기 위하여, 실리카 표면의 실라놀기를 커플링제와 반응시켜 특정한 작용기를 도입하는 표면 처리가 사용되고 있다. 본 연구에서는 초임계이산화탄 소를 용매로 사용하여 실리카 나노 파티클을 실란커플링제로 표면 개질 하는 반응을 연구하였다. 실란커플링제로 3-(trimethoxysilyl)propylmethacrylate (MPS), (3-Glycidoxypropyl) trimethoxysilane (GPS), (3-aminopropyl)trimethoxysilane (APS) 세 가지 종류를 사용하였다. TGA 측정 시 감소된 양은 실리카의 표면 개질된 실란커플링제의 비율로 볼 수 있다. MPS로 개질된 실리카는 6시간 반응 시 6%, 12시간 반응 시 7%, 24시간 반응 시 9% 감소하였다. APS로 개질된 실리카는 6, 12 및 24시간 반응 시 15% 감소를 보였다. GPS로 개질된 실리카는 6시간 반응 시 6%, 12시간 반응 시 10%, 24시간 반응 시 30% 감소되었다. 가수 분해 된 GPS의 수산기가 실리카 표면의 에폭 사이드 그룹과 반응 할 수 있기 때문에 반응 시간이 길어질수록 GPS 비율이 증가합니다.

표면 플라즈마 처리된 Cu nanoparticle (NPs)로 제작된 Organic photovoltaic (OPV)소자는 일잔 OPV 소자보 다 높은 효율성을 보여준다. Nps는 다양한 합성법으로 제조되어 29 nm의 지름을 가진 입자형태를 갖추었다. 이러한 Nps는 P3HT:PCBM과 결합하여 OPV 활성층으로 사용되었는데 적층방법으로 spin과 bar 코팅 방식을 사용하였다. 제작된 소자의 효율 평가에서 스핀코팅으로 제작된 P3HT:PCBM과 Nps가 결합된 P3HT:PCBM 이 각각 1.01과 4.39%로 Np의 효과로 인한 효율 증가를 볼 수 있었다. 바코팅 프로세스를 (8, 20, 50 um 갭)를 사용하였을 경우 20 um 갭의 바코터에서 스핀코터와 같은 두께의 활성층 두께를 보였다. 제작된 활성층은 바코터 그루브 특성으로 인해 트렌치 패턴이 형성되어 빛 흡수를 약화시켜 효율성을 저하시켰다.

본 연구에서는 SiO2 나노파티클-전도성 고분자 PEDOT:PSS 복합 구조 기반의 유기발광다이오 드용 내부 광추출 구조를 간단한 용액 공정으로 제작하였다. 또한, 다양한 농도의 SiO2 나노파티클을 PEDOT:PSS에 분산하여 그 구조를 확인하였고, 상부/하부 버퍼레이어의 도입이 내부 광추출 구조 형성에 미치는 영향에 관하여 알아보았다.

Due to the globalization of food supply have been growing, there have been a great demands for food safety and quality assuarance for on-site detection. On-site detetction isuue is the process should be fast, simple, user-friendly and require minimal equipments. Herein, we developed a Radial chromatography (RC) biosensor integrated with the immuno-gold nanoparticles-coated magnetic nanoparticle (AuNPs@Fe3O4) for specific separation and detection of the target bacteria, E. coli O157:H7, in sample. The immuno-AuNPs@Fe3O4 specifically binds to E.coli O157:H7 creating AuNP@Fe3O4-E.coli complexes and captured bacteria were concentrated by magnet. The complex can be identified with inner ring derived from the difference of mobility of free AuNPs@Fe3O4 on the RC sensor. Our results show that AuNPs@Fe3O4 based RC sensor has high sensitivity to the target bacteria over non-target bacteria with a detection limit of 103 CFU/ml. Our system offers a rapid and sensitive means of detecting E.coli O157:H7 with naked eyes, which can be applied to the field diagnosis.

Purpose: This research was conducted to produce the functional hydrogel ophthalmic lens containing nanoparticles. Methods: Carbon nanoparticles and PEGMEMA were used as additives for the basic combination containing HEMA, MA, and MMA, and the material was copolymerized with EGDMA as the cross-linking agent and AIBN as the initiator. The hydrogel lens was produced by a cast-mold method, and the materials were thermally polymerized at 100° C for an hour. The polymerized lens sample was hydrated in a 0.9% saline for 24 hours before the optical and physical characteristics of the lens were measured. Results: The refractive index, water content, contact angle, light transmittance, and tensile strength were measured to evaluate the physical and optical characteristics of the hydrogel lens. The results showed that the refractive index, water content, contact angle, UV-B light transmittance, UV-A light transmittance, visible light transmittance and tensile strength of the hydrogel lens polymer was 1.4019~1.4281, 43.05~51.18%, 31.95~68.61°, 21.69~58.11%, 35.59~84.26%, 45.85~88.06% and 0.0657~0.1649kgf, respectively. It showed an increase of refractive index and tensile strength while decreased in contact angle and light transmittance. Conclusions: This material can be used for ophthalmic lenses with high performance of wettability, ultraviolet ray blocking effect, and tensile strength. Furthermore, the visible light transmissibility was significantly increased at PEG 10%.

본 연구에서는 PVDF 분리막의 표면의 소수성을 향상시키기 위해 소수성 SiO2 나노 입자를 표면에 고정시키고, 표면에서 나노 입자가 막증류법에 미치는 영향을 확인하고자 한다. 소수성 나노 입자를 부착하는 물리적인 방법으로서 dip-coating 방법을 이용하였다. 나아가 물리적인 방법이 가지는 문제점인 약한 부착력을 해결하기 위해, 표면에 화학적으로 고정시키기 위한 방법으로 PVDF 표면에 OH기를 생성시켜 SiO2 입자의 OH기와의 탈수 반응을 이용하여 고정시켜준다. 이후 SiO2의 소수성 개질을 통해 막 표면의 소수성을 높여 주어 실험을 진행하였다. 앞선 두 가지 부착 방법을 통해 소수성 나노 입자가 PVDF 표면에 부착함에 따른 영향과 부착 방법에 따른 영향을 확인하였다.

Tin dioxide nanoparticles are prepared using a newly developed synthesis method of plasma-assisted electrolysis. A high voltage is applied to the tin metal plate to apply a high pressure and temperature to the synthesized oxide layer on the metal surface, producing nanoparticles in a low concentration of sulfuric acid. The particle size, morphology, and size distribution is controlled by the concentration of electrolytes and frequency of the power supply. The as-prepared powder of tin dioxide nanoparticles is used to fabricate a gas sensor to investigate the potential application. The particle-based gas sensor exhibits a short response and recovery time. There is sensitivity to the reduction gas for the gas flowing at rates of 50, 250, and 500 ppm of H2S gas.

Gd2O3:Eu3+ red phosphors were prepared by template method from crystalline cellulose impregnated by metal salt. The crystallite size and photoluminescence(PL) property of Gd2O3:Eu3+ red phosphors were controlled by varying the calcination temperature and Eu3+ mol ratio. The nano dispersion of Gd2O3:Eu3+ was also conducted with a bead mill wet process. Dependent on the time of bead milling, Gd2O3:Eu3+ nanosol of around 100 nm (median particle size : D50) was produced. As the bead milling process proceeded, the luminescent efficiency decreased due to the low crystallinity of the Gd2O3:Eu3+ nanoparticles. In spite of the low PL property of Gd2O3:Eu3+ nanosol, it was observed that the photoluminescent property was recovered after re-calcination. In addition, in the dispersed nanosol treated at 85 oC, a self assembly phenomenon between particles appeared, and the particles changed from spherical to rod-shaped. These results indicate that particle growth occurs due to mutual assembly of Gd(OH)3 particles, which is the hydration of Gd2O3 particles, in aqueous solvent at 85 oC.

We report on a simple and robust route to the spontaneous assembly of well-ordered magnetic nanoparticle superstructures by irreversible evaporation of a sessile single droplet of a mixture of a ferrofluid (FF) and a nonmagnetic fluid (NF). The resulting assembled superstructures are seen to form well-packed, vertically arranged columns with diameters of 5~0.7 μm, interparticle spacings of 9~2 μm, and heights of 1.3~3 μm. The assembled superstructures are strongly dependent on both the magnitude of magnetic field and the mixing ratio of the mixture. As the magnitude of the externally applied magnetic field and the mixing ratio of the mixture increase gradually, the size and interspacing of the magnetic nanoparticle aggregations decrease. Without an externally applied magnetic field, featureless patterns are observed for the γ-Fe3O4 nanoparticle aggregations. The proposed approach may lead to a versatile, cost-effective, fast, and scalable fabrication process based on the field-induced self-assembly of magnetic nanoparticles.

The structural formation of inorganic nanoparticles dispersed in polymer matrices is a key technology for producing advanced nanocomposites with a unique combination of optical, electrical, and mechanical properties. Barium titanate (BaTiO3) nanoparticles are attractive for increasing the refractive index and dielectric constant of polymer nanocomposites. Current synthesis processes for BaTiO3 nanoparticles require expensive precursors or organic solvents, complicated steps, and long reaction times. In this study, we demonstrate a simple and continuous approach for synthesizing BaTiO3 nanoparticles based on a salt-assisted ultrasonic spray pyrolysis method. This process allows the synthesis of BaTiO3 nanoparticles with diameters of 20-50 nm and a highly crystalline tetragonal structure. The optical properties and photocatalytic activities of the nanoparticles show that they are suitable for use as fillers in various nanocomposites.