Nanoparticles direct deposition

Nagare, S., Sagawa, J., Senna, M. (2007). Investigation and control of the uniformity of drug nanoparticles directly deposited on the particulate surfaces of excipient by RLD. J. Phy Conference Series., 59, 88-91. 

In general, there are two possibilities to prepare nanocarbon-supported metal(oxide) catalysts. The in situ approach grows the catalyst nanoparticles directly on the carbon surface. The ex situ strategy utilizes pre-formed catalyst particles, which are deposited on the latter by adsorption [94]. Besides such solution-based methods, there is also the possibility of gas phase metal (oxide) loading, e.g., by sputtering [95], which is used for preparation of highly loaded systems required for electrochemical applications not considered here. 

Specific, surface confined reactions not only directly involve catalysis but also the built-up of sdf-assembled multilayers (see Fig. 9.1 (3)) with co-functionalities for more complex (bio-) catalytic systems such as proteins or the directed deposition of active metals. Furthermore, SAM on flat substrates can be used for the study and development of e.g. catalytic systems, but are not useful for large scale applications because they have very limited specific surface. Here, nanoparticle systems covered with 3D-SAMs are the ideal solution of combining the advantages of high surface area, defined surface composition and accessibility of proximal active catalytic centers. 

Silver nanoparticles 928 Simulations 911 Single ion calibration e313 Single-piece electrode 75 Sinusoidal voltammetry 841 Site-directed deposition of polyelectrolytes 924 Skin e53, e55, e57 analysis e56 SLPT 87, 111... 

There have been two reports of direct deposition of gold nanoparticles onto oxide or carbon supports [76,77]. This is an important development from the viewpoint of avoiding contamination of the catalyst with chloride and gives rise to durable catalysts (see Sect. 6.3.3 later). 

The above discussed experiments could not quantitatively evaluate the contribution of the CO ligands in the observed metal core level shifts. To get rid of CO, a direct deposition of nanoparticles on amorphous carbon could appear as a solution. Hence, Ir was evaporated under vacuum and condensed on the substrate. 

Misner, M.J., Skaff, H., Emrick, T., Russell, T.P. Directed deposition of nanoparticles using diblock copolymer templates. Adv. Mater. 15, 221-224 (2003)... 

Underpotential deposition (UPD) is one useful way to the fabrication of metal mono-layer on metal nanoparticles [57]. UPD has been widely used in the deposition of metal atoms electrochemically onto another metal substrate at a potential slightly lower than the equilibrium potential for its reduction to metal [58]. This deposition is self-limiting, and atoms can only deposit up to single monolayer. When Pt is used as the core metal, several metals including Ru, Pd, and Ag can be directly deposited as monolayer via UPD [59]. 

Fig. 20.25 Rame spray pyrolysis (FSP) apparatus for producing ceramic nanoparticles and directly depositing them on a cooled substrate positioned above the flame. Particles arc simultaneously collected downstretun on a fiber filter for comparison (Reprinted with permission from Madler et al. 2006b, Copyright 2006 Elsevier)...

Silver-treated intravascular catheters have been also developed and tested for their ability to reduce infection rate. A conventional approach to coat devices with silver is the direct deposition of metallic silver onto the device surface by vapor coating, sputter coating, ion beam coating, or electrochemical deposition. More recent methods to incorporate silver in polymers consisted in the coordination of silver ions by anionic pus or direct formation of silver nanoparticles onto the surface of PU... 

We anticipate that this chapter would trigger more research efforts towards finding other innovative means to render them more robust as coatings, as these carbonaceous films can be made easily in large quantities and are much less expensive than other nano-structured carbon materials. Potential future directions could be, for instance, synthesis of polymer-carbon nanocomposite surfaces made up of carbon nanotubes, graphene or other carbon nanomaterials as well as flame synthesis of other soft materials which can be thermally triggered to crosslink or polymerize during nanoparticle network deposition. 

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