Gold nanoparticles formation

Gold Nanoparticles Formation by Living Alfalfa Plants... 

In order to observe the size and shape of the particles formed by free precipitation, a control sample was prepared with 0.015 M of HAuCU solution to which gradually the reducing agent NaBH4 (0.01 M) was added drop wise and mixed well. The yellow solution gradually transformed into a purple solution, indicating gold nanoparticle formation. 

Fig. 13.1 Effect of adding Ag ions on the rate of gold nanoparticle formation in [C4mim][BF4] time dependence of the absorption spectra of HAuCLt solutions during irradiation (a) without silver and (b) with silver nitrate (3.5 x 10 M). TEM images of solutions of HAUCI4 after 36 min of irradiation (c) without silver and (d) with silver nitrate (3.5 x 10 M). The addition of Ag to the solution accelerates the rate of formation of the gold nanoparticles. Reprinted from Ref. [47], Copjright (2010) with permission from the Royal Society of Chemistry...

Kinetic Studies of Gold Nanoparticles Formation in the Batch and in the Flow Microreactor System... 

Poke J., Ahner T. T., Delissen F., et al. Mechanism of gold nanoparticle formation in the classical citrate synthesis method derived from coupled In situ XANES and SAXS evaluation. J. Am. Chem. Soc. 132 no. 4 (2010) 1296-1301. 

Vesicles from thermally responsive PDEAEMA-/7-PNIPAm block copolymers were cross-linked via the in situ reduction of gold salt [114]. The resulting gold-decorated structures remained intact when the temperature was lowered below the LCST of PNIPAm. The strategy allows simultaneous gold nanoparticle formation and cross-linking of the... 

Andreu-Navarro, A., J. M. Fernandez-Romero, and A. Gomez-Hens. 2011. Determination of antioxidant additives in foodstuffs by direct measurement of gold nanoparticle formation using resonance light scattering detection. Anal. Chim. Acta 695 11-17. 

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

V. Armendariz, Bioreduction of Gold(III) to Gold(O) and Nanoparticle Formation by Oat and Wheat Biomasses The Use of Plants in Nanobiotechnology. Master Thesis, the University of Texas at El Paso, Chemistry Department, El Paso, TX, 2005, p. 107. 

The formation of Au nanoparticles can be easily monitored by following the appearance of a surface plasma resonance band around 520-540 nm (Fig. 6.1). Yeung et al. [33] observed that the efficiency of gold particle formation was different in different alcohols (n-pentanol > propan-2-ol > methanol). This is due to the air/water surface activity of the alcohols and the ability of the solute to scavenge the primary OH radicals at the bubble/liquid interface. 

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