• 한국재료학회지
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• 제28권1호
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• pp.1-5
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• 2018

Gas detection is necessary for various reasons, including the prevention of gas leakages and the creation of necessary environmental conditions. Among the gas detection methods, leakage of gas can be confirmed using materials that undergo color changes that are easily distinguished by the naked eye. Metal nanoparticles (NPs) experience variations in their absorption wavelengths under the localized surface plasmon effect (LSPR) with mechanical stresses, which change the distance between NPs. In this study, we attempted to detect the presence of gas utilizing the LSPR-related color change of a chain of Au NPs. The assembly of Au NPs, arranged in a chain shape, experienced a color change from dark blue to purple with a change in the distance between the NPs by applying a physical force, i.e., compression, stretching, and gas pressure. As the force of compression and the degree of stretching increased, the absorption wavelength shifted from doublet peaks at 650 and 550 nm to a singlet peak at 550 nm. Further, applying gas pressure caused an identical color change. With this result, we propose a method that could be applied to all gases that require detection based on gas pressure.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3735-3739
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• 2012

We have developed magnetically controllable gold nanoparticles by synthesizing superparamagnetic $Fe_3O_4$ core/gold shell nanoparticles. The core/shell particles have the capability of forming gold 1D chains in the presence of an external magnetic field. Here we demonstrate dynamic and reversible self-assembly of the gold 1D chain structures in an aqueous solution without any templates or physical or chemical attachment. The spatial configuration of gold chains can be arbitrarily manipulated by controlling the direction of a magnetic field. This technique can provide arbitrary manipulation of gold 1D chains for fabrication purpose. To demonstrate this capability, we present a technique for immobilization of the gold particle chains on a glass substrate.

• Journal of the Optical Society of Korea
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• 제11권2호
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• pp.76-81
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• 2007

The compound refractive X-ray lens (CRL) for focusing hard X-rays is investigated to determine the parameters such as the focal length, the focal spot size, and spatial distribution at the focal spot using a simple theoretical calculations and CRLs fabricated by the self-assembly method. The number of individual compound lenses are defined for the given focal length of 1 m. The X-ray energy of 1 to 40 keV is used in the calculations. The CRL for focusing hard X-rays which generated from the X-ray tube is fabricated by nanoparticle-polymer composite in the form of circular concaves. The self-assembly method is applied to form the nanoaluminum-poly (methly meth-acrylate) composite and carbon-polymer composite CRL lenses. Aluminum nanoparticles of 100 nm and carbon microparticles are diffused in the polymer solution then the high gravity up to 6000G is applied in it to form the concave lens shape. X-ray energy at 8 keV is used for characterization of the composite CRLs. The FWHM of intensity for the fabricated nanoaluminium composite CRL system, N=10 is measured as 1.8 mm, which would give about $70{\mu}m$ in FWHM at 1 m of the focal length.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.112-117
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• 2021

본 연구에서는 생물학적 공유결합인 다이타이로신 결합을 모방하여 비가역적 공유결합을 기반으로 한 펩타이드의 자기조립 방법을 연구하였다. 고밀도의 다이타이로신 결합을 달성하기 위해 Tyr-Tyr-Leu-Tyr-Tyr (YYLYY) 의 서열을 갖는 펩타이드 단량체를 선택하였다. 다이타이로신 결합으로 자기조립 된 펩타이드 나노입자는 가시광선 하에서 Ru(BPY)3Cl2 촉매를 사용하여 단일공정 광가교를 통해 합성되었다. 펩타이드 나노 입자의 크기에 대한 각 성분의 농도 효과는 동적 광산란, UV-Vis 분광법 및 투과 전자 현미경을 사용하여 확인하였다. 이를 통해 130 nm~350 nm범위의 펩타이드 나노입자의 크기별 최적의 합성 조건을 제시하였다.

• ETRI Journal
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• 제26권3호
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• pp.252-256
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• 2004

We formed silver nanocrystallites by the thermal decomposition of a $Ag^{+1}$-oleate complex, which was prepared by a reaction with $AgNO_{3}$ and sodium oleate in a water solution. The resulting monodispersed silver nanocrystallites were produced by controlling the temperature (290$^{\circ}$C). Transmission electron microscopic (TEM) images of the particles showed a 2-dimensional assembly of the particles with a diameter of $9.5{\pm}0.7nm$, demonstrating the uniformity of these nanocrystallites. An energy-dispersive X-ray (EDX) spectrum and X-ray diffraction (XRD) peaks of the nanocrystallites showed the highly crystalline nature of the silver structure. We analyzed the decomposition of the $Ag^{+1}$-oleate complex using a Thermo Gravimetric Analyzer (TGA) and observed the crystallization process using XRD.

• 세라미스트
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• 제21권3호
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• pp.283-292
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• 2018

Here, we introduce various type of inorganic nanostructure synthesized with functional nanoparticles and silica. From two decades ago, functional inorganic nanoparticles have been synthesized and highlighted, now we moved to next level of wet-chemical synthesis. By integrating functional nanoparticles with silica, we were able to synthesize multi-functional nanostructure, which expand the applications of nanoparticles to catalyst, drug carrier, sensors. In this context, silica has been spotlighted due to its versatility. Silica has highly biocompatible, relatively transparent and stable under harsh conditions. Thus it can be used as good supporter to synthesize complex multi-functional nanostructure when mixed with other functional nanoparticles. A various shape of complex nanostructures have been synthesized including core-shell type, yolk-shell type and janus type etc. In this paper, we have described the purposes of synthesizing silica noncomplex and various case studies for biomedical applications and self-assembly.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1539-1542
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• 2005

Self-assembled monolayers (SAMs) formed by the adsorption of alkanethiols, $HS(CH_2)_nX$, where X is an organic functional group, onto gold surfaces have attracted widespread interest as templates for the fabrication of molecular and biomolecular microstructures. Previously photopatterning has been thought of as being restricted to the micron scale, because of the wellknown diffraction limit. So, we have explored a novel approach to nanofabrication by utilizing a femtosecond laser coupled to a near-field scanning optical microscope (NSOM).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1048-1051
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• 2003

주사탐침현미경 (Scanning Probe Microsope, SPM)을 이용하여 직접 패터닝을 함으로써 hexanedithiol 분자의 임의 패턴을 금 표면에 형성하였다. 또한, hexanedithiol 분자는 양단에 thiol 그룹이 존재하여 금과 안정화 화학결합을 이룰 수 있으므로, 금 표면과결합을 이루고 있지 않는 상단의 thiol 그룹에 금 나노 입자를 고정함으로써 나노입자의 패턴을 제작하였다. SPM을 이용한 직접 패터닝 방법은 분자활성을 유지한 채로 임의 패턴을 수십 nm의 선폭으로 구현하는 것이 가능하므로, 나노입자 배열뿐만 아니라, 생화학물질의 패터닝을 통한 바이오 기술연구, 레지스트용 분자 패터닝과 시각 및 흡착 등의 계속적인 공정을 통한 다양한 나노구조 제작 등에 폭넓게 활용될 수 있다.

• Korea-Australia Rheology Journal
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• 제20권3호
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• pp.153-164
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• 2008

Modeling and experiments of three electrospinning systems have been presented and they are i) axisymmetric instabilities in electrospinning of various polymeric solutions, ii) non-isothermal modeling of polymer melt electrospinning, and iii) control of nanoparticle distribution and location via confined self-assembly of block copolymers during electrospinning. It has been demonstrated that predicted simulations are in good agreement with corresponding electro spinning experiments, and theoretical analysis provides fundamental understanding of phenomena that take place during electrospinning of various polymeric liquids.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.475-476
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• 2006

Self-assembled monolayers (SAMs) formed by the adsorption of alkanethiols, HS(CH2)nX, where X is an organic functional group, onto gold surfaces have attracted widespread interest as templates for the fabrication of molecular and biomolecular microstructures. Previously photopatterning has been thought of as being restricted to the micron scale, because of the well-known diffraction limit. So, we have explored a novel approach to nanofabrication by utilizing a femtosecond laser.