Micro metallic nanostructures

For their rich potential in various applications described in the previous section, the synthesis and assembly of various ZnO micro and nanostructures have been extensively explored using both gas-phase and solution-based approaches. The most commonly used gas-phase growth approaches for synthesizing ZnO structures at the nanometer and micrometer scale include physical vapor deposition (40, 41), pulsed laser deposition (42), chemical vapor deposition (43), metal-organic chemical vapor deposition (44), vapor-liquid-solid epitaxial mechanisms (24, 28, 29, 45), and epitaxial electrodeposition (46). In solution-based synthesis approaches, growth methods such as hydrothermal decomposition processes (47, 48) and homogeneous precipitation of ZnO in aqueous solutions (49-51) were pursued. 

Micro-Raman is a unique tool to address several fundamental aspects of SERS such as nature of the so-called hot spots (interstices of closely separated metal nanostructures), dependence of the enhancement on the orientation of the anisotropic nanostructures and aggregates with respect to polarization of the incident light. In this section, we will briefly highlight some of the important examples, where micro-Raman was employed to provide unique insight into these aspects. 

This work has been supported by the Russian Foundation for Basic Research grant 08-02-99042-r-ofi, a grant of the Program "Quantum Nanostructures" of the Presidium of RAS and a grant "Quantum bit on base of micro- and nanostructures with metal conductivity" of the Program "Technology Basis of New Computing Methods" of ITCS department of RAS. 

Electroactive Conducting Polymers for the Protection of Metals against Corrosion from Micro- to Nanostructured Films... 

In any cases, it is clear that adhesion of the ECP on the metal is an essential requirement for anticorrosion properties. It is also clear that O2 and electrolyte diffusion inside a coating has to be avoided. It is against these two main causes of failure that micro- and nanostructuring of coatings can bring new improvements. 

Lacaze P. C., Ghilane J., Randriamahazaka H. and Lacroix J.-C. (2010), Electroactive Conducting Polymers for the Protection of Metals against Corrosion from Micro- to Nanostructured Films , in Eftekhari A., Nanostructured conductive polymers, John Wiley Sons. 

NSL—often called colloidal lithography (CL)— is an effective technique using self-assemblies of polystyrene (PS) micro- or nano-particles on solid surfaces as 2-or 3-dimensional masks for metal deposition (Zhang et al. 2010). The size and shapes of the close-packed nanospheres and the holes between them, in addition to the metal deposition conditions, such as evaporation angle or specific deposition technique (e.g., sputtering, thermal deposition), influence the achieved metallic patterns. A different kinds of metallic nanostructures can he obtained (Fig. 3.10) ... 

Ultrasonic irradiation of a liquid leads to the generation of cavitation phenomenon which comprised of unique reaction fields in addition to physical and mechanical effects the formation of micro-meter sized bubbles, formation of bubbles with high temperature and high pressure conditions, formation of shock waves, and strong micro-stirring effects are produced. Table 5.1 shows representative ultrasound techniques to synthesize inorganic and metal nanoparticles and nanostructured materials. 

This chapter describes the synthesis, properties, and biomedical applications of cyanine and squaraine dyes encapsulated in CDs, CBs, Leigh-type tetralactam macrocycles, aptamers, and micro- or nano-particles. The optical and photochemical properties of supramolecular guest-host nanostructures that are based on intra-and intermolecular complexes of crown-containing styryl dyes with metal cations, and aggregates of carbocyanine dyes are discussed in a separate review [18]. 

Iron carbonyls have been also used to fabricate nanostructures of potential use in catalysis. In this context, the preparation at room temperature of nano-sized a-Fe single crystals over carbon micro-grid films has been reported. The particles were prepared by electron beam induced deposition using Fe(CO)s as precursor [77]. The use of a focused electron beam to induce metal deposition from carbonyl compounds opens a new route for the preparation of nano-sized metal particles. 

For the detailed study of reaction-transport interactions in the porous catalytic layer, the spatially 3D model computer-reconstructed washcoat section can be employed (Koci et al., 2006, 2007a). The structure of porous catalyst support is controlled in the course of washcoat preparation on two levels (i) the level of macropores, influenced by mixing of wet supporting material particles with different sizes followed by specific thermal treatment and (ii) the level of meso-/ micropores, determined by the internal nanostructure of the used materials (e.g. alumina, zeolites) and sizes of noble metal crystallites. Information about the porous structure (pore size distribution, typical sizes of particles, etc.) on the micro- and nanoscale levels can be obtained from scanning electron microscopy (SEM), transmission electron microscopy ( ), or other high-resolution imaging techniques in combination with mercury porosimetry and BET adsorption isotherm data. This information can be used in computer reconstruction of porous catalytic medium. In the reconstructed catalyst, transport (diffusion, permeation, heat conduction) and combined reaction-transport processes can be simulated on detailed level (Kosek et al., 2005). 

Flowever, a true catalytic effect is most probably present in transition-metal doped magnesium. A proof of this is the fact that nanostructured catalyst gives enhanced sorption properties compared to its micro-sized counterparts [226-229]. Hanada et al. also showed that after milling the catalyst is homogeneously distributed on a nanometer scale [230]. A possible interpretation of the catalytic effect may be the appearance of ternary magnesium-niobium oxides, which was evidenced by TEM [229, 231] and neutron diffraction [232]. Despite the abundant literature on... 

---