Nanosphere films

Meanwhile, the groups of Van Duyne and Bartlett have made special efforts to broaden the scope of nanosphere lithography to fabricate several new EC-SERS-active structural motifs [94, 99]. This most promising method can be used to produce nanostructured substrates with a precise control over the shape, size and interparticle spacing. In this case, a monolayer or a multilayer of highly ordered nanosphere films is used as the template for vacuum deposition or electrochemical deposition. As a result, three types of structured SERS substrate can be produced (i) physical vapor deposition on the nanosphere template... 

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... 

Figure 3. Various type of SERS active metallic nanostructures (a) metal-island films (b) metal-coated nanospheres (semi-nanoshells) (c) metal-coated random nanostructures and (d) polymer coatings embedded with metal nanoparticles. Inset An SEM image of silver-coated polystyrene spheres.

Vanduyne R.P., Hulteen J.C., Treichel D.A., Atomic-force microscopy and surface-enhanced Raman-spectroscopy. 1. Ag island films and Ag film over polymer nanosphere surfaces supported on glass, J. Chem. Phys. 1993 99 2101-211. 

As an example of composite core/shell submicron particles, we made colloidal spheres with a polystyrene core and a silica shell. The polar vapors preferentially affect the silica shell of the composite nanospheres by sorbing into the mesoscale pores of the shell surface. This vapor sorption follows two mechanisms physical adsorption and capillary condensation of condensable vapors17. Similar vapor adsorption mechanisms have been observed in porous silicon20 and colloidal crystal films fabricated from silica submicron particles32, however, with lack of selectivity in vapor response. The nonpolar vapors preferentially affect the properties of the polystyrene core. Sorption of vapors of good solvents for a glassy polymer leads to the increase in polymer free volume and polymer plasticization32. 

Fig. 4.2 TEM images of fabricated nanoparticles, (a) Isolated composite core/shell submicron particles, (b) Hollow silica submicron particles prepared by removing the polystyrene core to demonstrate the high quality of the formed sol gel shell of the composite nanospheres employed to prepare sensing colloidal crystal films...

Figure 15.2 (a) Atomic micrograph of silver film-over-nanospheres (AgFON). (b) Reflec-... 

Copper 18 mm diameter discs were utilized as substrates for glucose detection. After cleaning, approximately 10 lL of the nanosphere suspension (4% solids, 390 nm diameter) was drop coated onto each copper substrate and allowed to dry in ambient conditions.58 The substrates were then mounted into an electron beam deposition system for metal deposition (Kurt J. Lesker, Clairton, PA). Silver metal films (dm = 200 nm) were deposited over and through the sphere masks on the substrates.58 59... 

Polymeric carriers are biodegradable or water-soluble polymer matrices, typically in the form of colloidal-sized particles (microspheres or nanospheres), rods, or films. The active agent is entrapped within but not chemically bonded to the matrix. The drug is released in a sustained fashion as the polymer is dissolved or degraded, eroded, and finally resorbed [24,30,58-62]. 

Figure 10.2 Simulated and normalized experimental LSPR spectra from different Au nanostructures, (a, d) Au nanospheies with varying diameters (b, e) Au nanorods with varying aspect ratio (c, f) nanospheres loaded onto thin glass films with varying surface coverages.8 Horizontal and vertical arrows correspond to the progressions in AlsPR with increasing size or aspect ratio. (Reprinted with permission from L. M. Liz-Marzan, Langmuir 2006, 22, 32—41. Copyright 2006 American Chemical Society.)...

Figure 6.4 (a) Monoliths made of (from left to right) undoped ureasil, ureasil doped with Ag nanospheres, Au nanospheres, Au short nanorods, and Au long nanorods (b, c) ureasil disk-shaped films doped with a low concentration of Au-SiC>2 nanospheres (b) and short nanorods (c). Transparency, color uniformity, and flexibility can be seen clearly. [From Langmuir 2004, 20 (23), 10268.]... 

Penner S, Klotzer B, Jenewein B, Klauser F, Liu X, Bertel E (2008). Growth and stability of Ga Oj nanospheres. Thin Solid Films, 516, 4742... 

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