Gold monodispersity

The topic of gold nanospheres attracted the interest of several famous nineteenth century scientists such as Michael Faraday, Richard Zsigmondy, and Gustov Mie [43]. Interest diminished in the mid-twentieth century although some excellent contributions were made by Turkevich [42, 44], Frens [45], and Brust [46] in that period regarding the controlled preparation of nearly monodisperse colloidal suspensions. 

Frens, G. (1973) Controlled nucleation for the regulationof the particles size in monodisperse gold suspensions. Nature Physical Science, 241, 20-22. 

Electric-field-directed growth of gold nanorods in aqueous surfactant solutions. Advanced Functional Materials, 14, 571-579 (d) Jana, N.R. (2005) Gram-scale synthesis of soluble, near-monodisperse gold nanorods and other anisotropic nanoparticles. Small,... 

Figure 7. Synthetic steps for preparation of monodispersed gold nanoparticles by the SMAD method and digestive ripening. (Reprinted with permission from Ref. [29], 2002, American Chemical Society.)...

Thus, we see that the digestive ripening process leads to highly monodispersed nanoparticles that can come together to form ordered superstructures similar to atoms or molecules that form crystals from a supersaturated solution. Then if the superstructure formation can indeed be related to atomic/molecular crystallization, it should also be possible to make these supercrystals more soluble in the solvent with a change of temperature. Indeed, the optical spectra of the three colloids prepared by the different thiols discussed above exhibit only the gold plasmon band at 80 °C suggesting the solubilization of these superlattices at the elevated temperatures [49]. 

Interestingly, it was found that gold particles were not produced with monodisperse amorphous Si02 particles prepared by the method of Stober et al. [26]. Flence, silica... 

Jiang L-P, Xu S, Zhu JM, Zhang JR, Zhu JJ, Chen HY (2004) Ultrasonic-assisted synthesis of monodisperse single-crystalline silver nanoplates and gold nanorings. Inorganic Chem 43 5877-5883... 

We have recently synthesized monodisperse hexanethiolate-protected gold clusters, AU144-C6S, and determined an average core diameter of 1.7 0.3 nm, in support of the estimated molecular formula Au144-(C6H11S)52 (Fig. 30b) [334],... 

Frens G. Controlled nucleation for the regulation of particle size in monodispersed gold suspensions. NatPhys Sci 1973 241 20-22. 

The possibility of using electrostatic charge attraction has been exploited in the preparation of gold dendrimer encapsulated nanoparticles (DENs), which under appropriate conditions can be fully distributed along the surface of monodispersed MWCNTs (Fig. 3.21) [103]. 

The electroless plating method described above was used to prepare membranes that contain cylindrical gold nanotubules, which span the complete thickness of the membrane. As before, polycarbonate filtration membranes with cylindrical, monodisperse pores (Poretics, 6 [im thick, pore dia. = 30 nm) were used as the templates. The inside diameter (i.d.) of the nanotubules can be varied by varying the plating time (Fig. 14). At sufficiently long plating times, Au nanotubules with i.d.s of molecular dimensions (<1 nm) are obtained [106],... 

Miyake M, Torimoto T, Sakata T, Mori H, Yoneyama H (1999) Photoelectrochemical characterization of nearly monodispersed CdS nanoparticles-immobilized gold electrode. Langmuir 15 1503-1507 Torimoto T, Tsumura N, Miyake M, Nishizawa M, Sakata T, Moii H, Yoneyama H (1999) Preparation and photoelectrochemical properties two dimensionally organized CdS nanoparticle thin films. Langmuir 15 1853-1858... 

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... 

Lu LH, Wang HS, Zhou YH, Xi SQ, Zhang HJ, Jiawen HBM, Zhao B (2002) Seed-mediated growth of large, monodisperse core-shell gold-silver nanoparticles with Ag-like optical properties. Chem Commun, pp 144-145... 

It took almost a century from the time Faraday obtained the first monodispersed colloid, his well-known gold sol (22), until the works of Steele (l) and Heller (2,3) mentioned earlier. Therefore, it is even more surprising that all one needs to obtain... 

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