금 나노입자의 크기에 따른 광학적 특성변화

입팔 유샤프,이일수,배홍섭,김정수,장준혁,권문호,홍성욱 한국물리학회 2014 새물리 Vol.64 No.3

Three different-sized gold nanoparticles were synthesized to investigate the size dependence of the optical absorbance in aqueous solutions of nanoparticles. The particles were spherical in shape on the TEM images and had average diameters of 14.49 ± 1.12 nm, 16.11 ± 1.32 nm, 24.77 ± 1.76 nm, respectively. The resonance wavelength of the surface plasma was red-shifted in the UV-VIS spectra with increasing diameter of the particles. The spectra also showed that the optical absorbance increased as the particle size increased, which is as expected. Also, the concentration dependence of the absorbance showed that the absorbance increased with increasing particles size. 금 나노입자 수용액에서 광학적 특성이 입자의 크기에 따라 어떻게 변하는지를 관찰하기 위해 크기가 다른 금 나노입자를 형성하였다. TEM (투과전자현미경)으로 관찰한 금 나노입자의 모양은 구형이고 그 직경은 각각 14.49 ± 1.12 nm, 16.11 ± 1.32 nm, 24.77± 1.76 nm이었다. UV-VIS(적외선-가시광선) 스펙트럼에서 표면 플라즈마 공명의 파장은 입자의 크기가 증가함에 따라 적색편이 됨이 관찰되었다. 또한 흡수력 (absorbance)도 입자의 크기가 증가함에 따라 증가함이 관찰되었다. 나노입자의 농도에 따른 흡수력의 변화를 관찰하기 위해 여러 농도의 나노입자 수용액을 만들었다. UV-VIS 스펙트럼을 통해 농도가 커짐에 따라 흡수력의 피크는 증가함이 관찰되었고, 이 피크의 증가는 입자의 크기에 비례함을 볼 수 있었다.

Synthesis of fullerene[C60]-gold nanoparticles using non-ionic surfactants polysorbate 80 and brij 97

고원배,Byoung Eun Park,Young Min Lee,황성호 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.1

The synthesis of gold nanoparticles was investigated with non-ionic surfactants such as polysorbate 80, brij 97 and KAuCl4 in water. The products of gold nanoparticle were well dispersed in water and investigated by UV-vis spectra and TEM. The reaction time for the synthesis of gold nanoparticles was investigated by monitoring the change of color and the change of the peak of the UV-vis spectra in the absence of ultrasonic irradiation and in the presence of ultrasonic irradiation. Gold nanoparticles reacted with 4-aminothiophenol in water and then, diethylether was added, and fullerene[C60] in toluene which was stirred for 24 h. The fullerene[C60]-gold nanoparticles were characterized by UV-vis and MALD-TOF-MS spectra.

Synthesis of fullerene[C60]-silver nanoparticles using various non-ionic surfactants under microwave irradiation

Jeong Ho Lee,Byoung Eun Park,Young Min Lee,Sung Ho Hwang 한국물리학회 2009 Current Applied Physics Vol.9 No.2

Silver nanoparticles were synthesized from the reaction of silver nitrate (AgNO3) with a 1 wt% aqueous solution of polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, and Brij 97, respectively, under microwave irradiation. The resulting nanoparticles were effectively dispersed throughout water and characterized by UV–vis spectra and transmission electron microscopy (TEM). The reaction time of 45 s was investigated by monitoring the color change of the nanoparticle solution. The peaks in the UV–vis spectra showed surface plasmon resonance characteristics inherent in silver nanoparticles. The nanoparticles were reacted with 4-aminothiophenol in water, followed by addition of diethyl ether and fullerene[C60] in toluene and stirring for 24 h. The resulting fullerene[C60]-silver nanoparticles were characterized by UV–vis and MALDI–TOF–MS spectra. Silver nanoparticles were synthesized from the reaction of silver nitrate (AgNO3) with a 1 wt% aqueous solution of polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, and Brij 97, respectively, under microwave irradiation. The resulting nanoparticles were effectively dispersed throughout water and characterized by UV–vis spectra and transmission electron microscopy (TEM). The reaction time of 45 s was investigated by monitoring the color change of the nanoparticle solution. The peaks in the UV–vis spectra showed surface plasmon resonance characteristics inherent in silver nanoparticles. The nanoparticles were reacted with 4-aminothiophenol in water, followed by addition of diethyl ether and fullerene[C60] in toluene and stirring for 24 h. The resulting fullerene[C60]-silver nanoparticles were characterized by UV–vis and MALDI–TOF–MS spectra.

UV-Vis Spectra of N,N`-Bis (4`-Aminophenyl)-1,4-quinonenediimine Doped with H₄SiW₁₂O₄₀

Jian Gong,Xiu Jun Cui,Ya Guang Chen,Zhong Wei Xie,Lun Yu Qu 한국고분자학회 2004 Macromolecular Research Vol.12 No.1

Spectroscopic Studies on the Oxidation of Catechin in Aqueous Solution

Bark, Ki-Min,Yeom, Ji-Eun,Yang, Jeong-Im,Yang, Ik-Jun,Park, Chul-Ho,Park, Hyoung-Ryun Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.9

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

Spectroscopic Studies on the Oxidation of Catechin in Aqueous Solution

박기민,Chul-Ho Park,Ik-Jun Yang,Jeong-Im Yang,Ji-Eun Yeom,박형련 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.9

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

Spectrophotometric Determination of Maximum Loading Capacity of a Dendrimer

전영진 대한화학회 2023 대한화학회지 Vol.67 No.4

A series of hydrophobic dodecyl-terminated 6th-generation poly(amidoamine) dendrimer (H)-encapsulated cadmium sulfide ((CdS)n@H) nanoparticles in a co-solvent (toluene: methanol = 6.8: 3.2 v/v) are synthesized. The diameters of CdS nanoparticles within the dendrimer were estimated by analyzing the positions of the first excitonic absorption peaks of CdS in UV-vis spectra. The size of the CdS nanoparticle within the dendrimer shows a saturation value as the CdS/H ratio (n) increases, which is believed to be due to the limited physical size of the void cavity within the dendrimer. This simple and convenient method of estimating the saturation of the size of CdS in dendrimers may be useful in determining the maximum void space within other dendrimers under various solvent conditions.

Microwave-assisted Solvent-free Synthesis of Some Dimethine Cyanine Dyes, Spectral Properties and TD-DFT/PCM Calculations

Xiang-Han Zhang,Lan-Ying Wang*,Gao-Hong Zhai,Zhen-Yi Wen,Zu-Xun Zhang 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.12

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the p-p* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ?2%.

Preparation of colloidal silver nanoparticles by chemical reduction method

송기창,Sung Min Lee,Tae Sun Park,Bum Suk Lee 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.1

Colloidal silver nanoparticles were obtained by chemical reduction of silver nitrate in water with sodium borohydride (NaBH4) in the presence of sodium dodecyl sulfate (SDS) as a stabilizer. The obtained nanoparticles were characterized by their UV-vis absorption spectra and transmission electron micrograph (TEM) images. The UV-vis absorption spectra showed that NaBH4 served not only as a reducing agent but also as a stabilizer, which protects the aggregation of silver nanoparticles. The TEM images showed that the particles were dispersed better with increasing the NaBH4 concentration.

Investigation of phase stability of poly(1-oxotrimethylene)-dissolved aqueous solutions containing ZnCl2/CaCl2/LiCl: Influence of boric acid introduction and aging time

채동욱,장한별,김병철 한국유변학회 2018 Korea-Australia rheology journal Vol.30 No.1

Poly(1-oxotrimethylene) (POTM) was dissolved in aqueous solutions containing ZnCl2, CaCl2, and LiCl, and the effects of boric acid introduction on the phase stability of the POTM solutions over various aging times were investigated. In the absence of boric acid, aging at 70°C for 8 h notably reduced the loss tangent (tanδ) for the 7.0 wt.% POTM solutions. Addition of boric acid into unaged solutions had little effect on tanδ over the frequency range measured, regardless of its content, whereas addition of 0.3-1.0 wt.% of boric acid into aged solutions increased tanδ. The dynamic viscosity of the POTM solutions with 1.0 wt.% boric acid was affected little by aging time. Conversely, the POTM solutions without boric acid exhibited increased dynamic viscosity in the low-frequency range with aging time. In addition, the slope of the solutions in the Cole-Cole plot decreased with increasing aging time in the absence of boric acid, whereas aging time had little effect in the presence of 1.0 wt.% boric acid. For dilute POTM solutions (i.e., 0.5 g/dL), the reduced viscosity decreased with increasing aging time in the absence of boric acid, while it was affected little in solutions with the addition of 1.0 wt.% boric acid. In the UV-Vis spectra, the aging-time-dependent increase of the absorbance peak at 390 nm was associated with the generation of a chromophoric complex in the POTM solutions. Conversely, the disappearance of the peak due to the addition of boric acid indicated suppression of complex formation.