• 한국염색가공학회지
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• 제21권6호
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• pp.39-45
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• 2009

The importance of nano gold particles has been increased in the field of bio physics and medicine, recently. In this regard, the study aims to analyze how the harmless nano gold particles can be transformed by respective variables. In this study, electrospun PU nano-webs were impregnated with aqueous $HAuCl_4$ solution and UV light was irradiated on the webs. Au-ions were reduced to nano particles by photocatalytic reduction and these nano gold particles were characterized by SEM, UV-vis, Zetasizer, Spectrophotometer, EDS. $HAuCl_4$ solution concentration and UV irradiation time have heen examined to change the amount of absorption. Nano gold particles size and UV-Vis absorbances were increased with $HAuCl_4$ solution concentration and UV irradiation time.

• 대한화장품학회지
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• 제22권2호
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• pp.52-69
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• 1996

Nano-Sized TiO$_2$ particles with diameter between 2 and 5 nm are synthesized in Water/Triton X-100/n-Hexane microemulsion. Particles show the amorphous structure and partially hydroxide form. The optical absorbance of particles appears at 250nm and band edge at 340nm. Gold metal is deposited on the surface of TiO$_2$ particles by reduction reaction of Au(III) ion with sodium hypophosphite. The size of gold-deposited particles is 20nm, and the optical absorbance appears at 270nm and at 550nm. So particles show the red color. The dense precipitation is formed by aggregation in the TiO$_2$ nano-sized particles of about 5nm size. But the bulky precipitation is formed by agglomeration phenomena in the gold-deposited particles of 20nm size. And also gold-deposited particles is easily dispersed by being re-dispersed in PEG/Water solution. This study has compared those things measuring the SPF characteristics of the cosmetics made of the synthesized particles. If the particle size is controlled appropriately, then the SPF value will be higher, or more colorless cosmetics will be made.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.237-242
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• 2013

This experiment was conducted for the purpose of developing such a sensor that can quickly sense dopamine concentration by using chitosan-gold nanoshell. Chitosan nano particles were reacted with gold nano particles so as to synthesize chitosan-gold nanoshell, and the size of the synthesized product was about 150 nm. When dopamine was reacted with chitosan-gold nanoshell, the size of it was not definitely changed, but dopamine was well reacted with chitosan-gold nanoshell, and it generated SERS (surface-enhanced Raman scattering), which led to a clear difference in the intensity of Raman scattering within the range of dopamine concentration (1 mM-10 mM). When Raman scattering was intensity marked on chitosan-gold nanoshell by employing a calibration curve according to dopamine concentration, a straight line whose margin of error was narrow was earned.

• 센서학회지
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• 제18권3호
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• pp.226-233
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• 2009

In this study, the optical properties of localized surface plasmon resonance sensor using optical fiber was analyzed as the variation of a size and surface density of gold nano particles on the etched optical fiber surface. It is shown that a size and surface density of gold nano particles on optical fiber surface are controlled by $Na_3$ citrate quantity and pH of gold colloid solution. To measure the sensitivity, peak wavelength of absorbance spectrum was detected as the reflective index of the solution. The sensor sensitivity is linearly dependent on the size and surface densities of gold nano particles from the results of optical experiments.

• Elastomers and Composites
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• 제34권1호
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• pp.45-52
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• 1999

본 논문에서는 미세 상분리된 블럭 공중합체 박막의 특이상에서 금 입자들이 어떻게 자기응집(self assemble) 되고 잘 배열된 패턴을 형성하는지를 살펴보았다. 본 연구에서는 원통형 모폴로지를 갖는 PS-PB-PS 삼블럭 공중합체(30wt% PS) 박막(${\sim}100nm$)을 0.1wt% 톨루엔 용액으로부터 캐스팅하여 고분자 박막 형판(template)으로 사용하였다. 각각의 상이한 용매 증발조건으로부터 PB matrix내에 수평배열 PS cylinder와 수직 PS cylinder를 함께 갖는 막이 얻어졌다. 블럭 공중합체박막의 표면 및 bulk 몰폴로지를 살펴보기 위하여 단면투과전자현미경(TEM)을 사용하였다. Nano-scale 패턴을 얻기 위하여는 소량의 금입자를 블럭 공중합체 박막상에 증발시켰다. 캐스팅된 상태 그 대로의 박막형판이 사용되어질때 금입자들은 표면 장력이 적은 PB상에 우선적으로 자기응집(self as-semble)하여 비교적 잘 배열된 nano-scale의 패턴을 형성하였다. 그러나 열처리(annealing)에 의하여 표면장력이 적은 PB-rich충이 형성된 후에는 금입자의 자기응집에 의한 패턴은 관찰되지 않았다.

• 대한기계학회논문집A
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• 제28권7호
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• pp.999-1005
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• 2004

A new stamp fabrication technique for the soft lithography has been developed in the range of several microns by means of a nano-replication printing (nRP) process. In the nRP process, a figure or a pattern can be replicated directly from a two-tone bitmap figure with nano-scale details. A photopolymerizable resin was polymerized by the two-photon absorption which was induced by a femtosecond laser. After the polymerization of master patterns, a gold metal layer (about 30 ㎚ thickness) was deposited on the fabricated master patterns for the purpose of preventing a join between the patterns and the PDMS, then the master patterns were transferred in order to fabricate a stamp by using the PDMS (poly-dimethylsiloxane). In the transferring process, a few of gold particles, which were isolated from the master patterns, remained on the PDMS stamp. A gold selective etchant, the potassium iodine (KI) was employed to remove the needless gold particles without any damage to the PDMS stamp. Through this work, the effectiveness of the nRP process with the PDMS molding was evaluated to make the PDMS stamp with the resolution of around 200 ㎚.

• 한국재료학회지
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• 제21권10호
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• pp.525-531
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• 2011

Two dimensional (2D) arrays of noble metal nanoparticles are widely used in the sensing of nanoscale biological and chemical events. Research in this area has sparked considerable interest in many fields owing to the novel optical properties, e.g., the localized surface plasmon resonance, of these metallic nanoarrays. In this paper, we report successes in fabricating 2D arrays of gold nano-islands using nanosphere lithography. The reproducibility and the effectiveness of the nano-patterning method are tested by means of spin coating and capillary force deposition. We found that the capillary force deposition method was more effective for nanospheres with diameters greater than 600 nm, whereas the spin coating method works better for nanospheres with diameters less than 600 nm. The optimal deposition parameters for both methods were reported, showing about 80% reproducibility. In addition, we characterize gold nano-island arrays both geometrically with AFM as well as optically with UV-VIS spectrometry. The AFM images revealed that the obtained nano-arrays formed a hexagonal pattern of truncated tetrahedron nano-islands. The experimental and theoretical values of the geometric parameters were compared. The 2D gold nano-arrays showed strong LSPR in the absorption spectra. As the nano-islands increased in size, the LSPR absorption bands became red-shifted. Linear dependence of the plasmon absorption maximum on the size of the gold nano-islands was identified through the increment in the plasmon absorption maximum rate for a one nanometer increase in the characteristic length of the nano-islands. We found that the 2D gold nano-arrays showed nearly seven-fold higher sensitivity of the absorption spectrum to the size of the nano-islands as compared to colloidal gold nano-particles.

• 센서학회지
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• 제17권2호
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• pp.95-99
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• 2008

Various etching methods of optical fiber and formation of metal nano particles on the optical fiber have been proposed for fabrication of fiber optic localized surface plasmon resonance (FO LSPR) biosensors. Different types of etched optical fiber are possible by removing the cladding of optical fiber using HF (hydrofluoric acid) solution and BHF (buffered hydrofluoric acid) solution, which results in improved surface roughness when BHF solution is used. Localized surface plasmon can be formed and measured by formation of silver and gold nano particles on the etched optical fiber. The characteristics of the etched optical fiber and metal nano particles on the etched surface of the optical fiber play a key role in dictating the sensitivity of the LSPR sensors, so that the proposed results can be expected to be applied for related research on fiber optic based biosensors.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2007년도 학술발표회 논문집
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• pp.537-538
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• 2007

• Environmental Engineering Research
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• 제16권2호
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• pp.81-90
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• 2011

Different weight percentages of Ag, Pt, and Au doped nano $TiO_2$ were synthesized using the acetic acid hydrolyzed sol-gel method. The crystallite phase, surface morphology combined with elemental composition and light absorption properties of the doped nano $TiO_2$ were comprehensively examined using X-ray diffraction (XRD), $N_2$ sorption analysis, transmission electron microscopic (TEM), energy dispersive X-ray, and DRS UV-vis analysis. The doping of noble metals stabilized the anatase phase, without conversion to rutile phase. The formation of gold nano particles in Au doped nano $TiO_2$ was confirmed from the XRD patterns for gold. The specific surface area was found to be in the range 50 to 85 $m^2$/g. TEM images confirmed the formation a hexagonal plate like morphology of nano $TiO_2$. The photocatalytic activity of doped nano $TiO_2$ was evaluated using 4-chlorophenol as the model pollutant. Au doped (0.5 wt %) nano $TiO_2$ was found to exhibit higher photocatalytic activity than the other noble metal doped nano $TiO_2$, pure nano $TiO_2$ and commercial $TiO_2$ (Degussa P-25). This enhanced photocatalytic activity was due to the cathodic influence of gold in suppressing the electron-hole recombination during the reaction.