Nanospheres

Freunscht P, Van Duyne R P and Schneider S 1997 Surface-enhanced Raman spectroscopy of trans-stilbene adsorbed on platinum- or self-assembled monolayer-modified silver film over nanosphere surfaces Chem. Phys. Lett. 281 372-8... 

Yang W H, Hulteen J 0, Schatz G G and Van Duyne R P 1996 A surface-enhanced hyper-Raman and surface-enhanced Raman scattering study of trans-1,2-bis(4-pyridyl)ethylene adsorbed onto silver film over nanosphere electrodes. Vibrational assignments experiments and theory J. Chem. Phys. 104 4313-26... 

The nonporous spherical gels for PCHdC are often specially prepared for research purposes. However, nonporous polystyrene/divinylbenzene beads. Solid Bead, can be obtained in various particle sizes from Jordi Associates, Inc. (Bellingham, MA). Columns packed with these gels can be used for HdC of the polymers that are currently analyzed using polystyrene/divinylbenzene SEC columns. Fumed silica nanospheres are offered by Cabot (Tuscola, IL) (17), and nonporous silica (NPS) microspheres are offered by Micra Scientific, Inc. (Northbrook, IL). These nonporous silica gels may also be used for HdC. 

Toth E, Hehn L, Merbach AE (2002) Relaxivity of MRI Contrast Agents. 221 61-101 Tovar GEM, Krauter I, Gruber C (2003) Molecularly Imprinted Polymer Nanospheres as Fully Affinity Receptors. 227 125-144... 

Kroger N, Deutzmann R, Sumper M (1999) Polycationic peptides from diatom biosilica that direct silica nanosphere formation. Science 286 1129-1132... 

A simple geometric model, based on the hypothesis that water plus surfactant are subdivided in nanospheres and that their total surface is fixed by the amount of surfactant, can predict the dependence of the micellar radius (r) on R and that of the micellar concentration on R and on the surfactant concentration. 

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. 

There are very many papers in the literature that address some aspect of gold nanospheres. In particular, their plasmon response (see Section 7.3.1.1) has been well studied, as has their agglomeration [50-52] and the manner in which they can be assembled into highly ordered colloidal crystals [50, 53, 54]. The latter are interesting and will be further discussed in Section 7.3.8.2. Conjugation of gold nanospheres with proteins and antibodies, for use as a stain in microscopy [55] or possibly, in medical applications [23], is another rich field. 

Pissuwan, D., Cortie, C.H., Valenzuela, S. and Cortie, M.B. (2007) Gold nanosphere-antibody conjugates for therapeutic applications. Gold Bulletin, 40,... 

Harris, N., Ford, M.J. and Cortie, M.B. (2006) Optimization of plasmonic heating by gold nanospheres and nanoshells. The Journal of Physical Chemistry B, 110, 10701-10707. 

Figure 3.2 Extinction spectra of colloidal water solutions of gold nanospheres and nanorods. Dotted curve nanospheres (diameter 15-25 nm). Solid curve nanorods, low aspect ratio. Dashed curve nanorods, high aspect ratio. Extinction is normalized at about 520 nm. (Reproduced with permission from Royal Society of Chemistry [10]).

Figure 3.8 Schematic view of enhanced field distribution in the vicinity of a dimerof noble metal nanospheres. (Reproduced with permission from The Japan Society of Applied Physics [12]).

Figure 3.9 Near-field two-photon excitation images of gold nanosphere dimers, (a) Topography. Scale bar 500 nm. (b) and (c) Two-photon excitation images. The excitation wavelength is 780 nm. Incident polarization directions are indicated by arrows. The approximate positions ofthe particles are indicated by circles. (Reproduced with permission from The Japan Society of Applied Physics [12]).

Hosokawa, C., Yoshikawa, H. and Masuhara, H. (2004) Optical assembling dynamics of individual polymer nanospheres investigated by singleparticle fluorescence detection. Phys. Rev. E, 70, 061410-1-061410-7 (2005) Cluster formation of nanoparticles in an optical trap studied by fluorescence correlation spectroscopy. Phys. Rev. E, 72, 021408-1-021408-7. 

Si02 nanospheres are fused onto the surface of glass at 650 °C, resulting in a a surface that reflects nearly no light. 

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