Gold nanoparticles micelles

Figure 24. TEM images of different gold nanoparticles grown in the micelles of diblock copolymers, a 6nm, b 4nm, c 2.5 nm.

After the mixture had been dried, the remaining residue (CD-capped gold nanoparticles + compound 3) was found to express insolubility in dry CHCfi but the solubility was restored when water was used in the equilibration of the chloroform. In our judgment, this finding clearly makes it apparent that there must be some water necessary for the efficient phase transfer of the nanoparticles into CHCfi. This finding leads to the conclusion that the idealized structure that has been proposed for the nanoparticles after they have been transferred to the chloroform phase (Scheme 2) has some aspects that must be similar to the structure of reverse micelles. We come to the conclusion that these nanoparticle-centered assemblies are similar in a conceptual way to gold-filled reverse micelles. (124 words)... 

Spirin MG, Brichkin SB, Razumov VF (2005) Synthesis and stabilization of gold nanoparticles in reverse micelles of aerosol OT and triton X-100. Colloid J 67 485-490... 

Herrera AP, Resto O, Briano JG, Rinaldi C (2005) Synthesis and agglomeration of gold nanoparticles in reverse micelles. Nanotechnology 16 S618-S625... 

Chiang CL (2000) Controlled growth of gold nanoparticles in aerosol-OT/sorbitan monooleate/isooctane mixed reverse micelles. J Colloid Interface Sci 230 60-66... 

Lin J, Zhou WL, O Connor CJ (2001) Formation of ordered arrays of gold nanoparticles from CTAB reverse micelles. Mater Lett 49 282-286... 

Xu J, Han X, Liu H L, Hu Y (2005) Synthesis of monodisperse gold nanoparticles stabilized by gemini surfactant in reverse micelles. J Dispers Sci Technol 26 473-476... 

Azene H, Sigers S, Johnson V (2003) Formation and characterization of gold nanoparticles in dioctyl sulfosuccinate/isooctane and dioctyl sulfosuccinate/phosph-atidyulcholine/isooctane mixed reverse micelles. Abstr Pap Am Chem Soc 225 U23-U23... 

Chiang CL (2001) Controlled Growth of Gold Nanoparticles in AOT/C12E4/Isooctane Mixed Reverse Micelles. J Colloid Int Sci 239 334-341... 

Scheme 2 Schematic of a seed-mediated, surfactant-assisted gold nanorod synthesis. The small black dots represent Ag+ ions, the orange stars are CTAB molecules forming micelles, the yellow circles and green squares are AuCLf and AuC12 , respectively, forming complexes with the CTAB micelles. Freshly-prepared gold nanoparticle seeds are injected into the growth solution in the final step of the nanorod synthesis [166]. (Copyright 2008, American Chemical Society)...

Figure 12 TEM images of gold nanoparticles of different size prepared in diblock copolymer micelles, (a) 6nm, (b) 4nm, (c) 2.5 nm. (Reprinted from G. Schmid, D.V. Talapin, E.V. Shevchenko in ed. G. Schmid Nanoparticles. From Theory to Application, Wiley-VCH, Weinheim 2004, with permission from Wiley-VCH)...

Ordered assemblies of gold nanoparticles generated by this micelle techniqne seem to become of importance on the rapidly developing held of nanobiotechnology. Regularly arranged spots of gold serve as anker places for biomaterials, as has impressively been demonstrated by Spatz et... 

There have been fewer reports on the particle size dependence of catalysis by platinum-catalyzed redox reactions. A report by Sharma et al. [21] showed that platinum colloidal nanoparticles do not demonstrate the same dependence on particle size as gold nanoparticles do for the reduction of hexacyanoferrate (III) by thiosulfate [19]. Platinum nanoparticles protected by sodium di(2-ethylhexyl) sulfosuccinate (synthesized by a reverse micelle technique) exhibit an optimum size ( 38 nm) for the reduction of ferricyanide by thiosulfate (Fig. 18.2). The reason for an optimum particle size is not fully understood however, they proposed the following explanation a shift in the Fermi level occurs as the diameter is increased. 

Selvan and coworkers167168 utilized a block copolymer micelle of polystyrene-block-poly(2-vinylpyridine) in toluene exposed to tetrachloroauric acid that was selectively adsorbed by the micelle structure. On exposure of this solution to pyrrole monomer, doped PPy was obtained concurrently with the formation of metallic gold nanoparticles. The product formed consisted of a monodispersed (7-9 nm) gold core surrounded by a PPy shell. Dendritic nanoaggregate structures were also reported... 

Calandra, P., Giordano, C., Longo, A. and Turco Liveri, V. (2006) Physicochemical investigation of surfactant-coated gold nanoparticles synthesized in the confined space of dry reversed micelles. Mater. Chem. Phys., 98, 494-499. 

Esumi K, Ghosh SK, Kundu S, Mandal M, Pal T. 2002. UV photoactivation for size and shape controlled synthesis and coalescence of gold nanoparticles in micelles. Langmuir 75 7792-7797. 

Figure 4.32 TEM images of gold nanoparticles of various sizes generated in micelles of different sizes and by different loading ratios, (a) 6nm, (b) 4nm, (c) 2.5 nm.

FIGURE 5.7 Principle of block copolymer lithography for spatially defined placing of gold nanoparticles on surfaces [16]. (a) Block copolymer stmcture, (b) formation of micelles with a metal ion core, and (c) formation of thin hlms hy dip coating and plasma treatment to remove organic layer. (See insert for color representation of the figure.)... 

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