Nanoscale surface modifications

Caruso F (2003) Nanoscale surface modification via sequential electrostatic assembly. In Caruso F (ed) Colloids and colloid assemblies. Wiley, Weinheim... 

This chapter presents the current trends in this area with emphasis on load-bearing orthopaedic and dental implants. A detailed account on the general and the localized corrosion of conventional metalhc implants is provided. Novel fabrication strategies of nanostructured hydroxyapatite-based coatings and their roles as barrier coatings are presented. Impacts of nanoscale surface modifications on the corrosion resistance of permanent implants and novel bioresorbable implants based on magnesium alloys are highhghted. 

There are no comprehensive standards or literature available on the corrosion behaviour of such nanostmctured implants. Figure 15.4 schematically represents a few likely outcomes. The following sections discuss the effeets of these modifications on the corrosion resistance of orthopaedic and dental implants More specifically, Section 15.4 discusses the effect of nanoscale surface modifications on the corrosion behaviour of titanium based alloys. Section 15.5 discusses nanoceramic coatings with emphasis on HA coatings. Current approaches in making nanostmctured coatings and nanocomposites for Mg based resorbable implants are presented in Section 15.6. 

Reported works concerning corrosion resistance of implants after nanoscale surface modifications are scanty. Depending upon the type of the implant material and the nature of modification, corrosion resistance of modified implants can be superior or inferior. For example, a thick anodized porous oxide layer improves... 

Nanoscale Surface-Modification Techniques Using the Scanning Tunneling Microscope... 

Although some impressive features have been fabricated, the mechanism for nanoscale surface modification via voltage/current pulses is not totally clear and may well vary with tip/substrate combinations as well as length, direction and magnitude of the voltage and current pulses. The presence or absence of air and other surface contaminants is also important to the process. In some cases different mechanisms have been proposed by different experimenters for the same conditions (Table I). 

Laser ablation of polymer films has been extensively investigated, both for application to their surface modification and thin-film deposition and for elucidation of the mechanism [15]. Dopant-induced laser ablation of polymer films has also been investigated [16]. In this technique ablation is induced by excitation not of the target polymer film itself but of a small amount of the photosensitizer doped in the polymer film. When dye molecules are doped site-selectively into the nanoscale microdomain structures of diblock copolymer films, dopant-induced laser ablation is expected to create a change in the morphology of nanoscale structures on the polymer surface. 

Site-Selective Modification of the Nanoscale Surface Morphologf 211... 

Site-Selective Modification of the Nanoscale Surface Morphology of Dye-Doped Copolymer Films Using Dopant-Induced Laser Ablation... 

As aforementioned, diblock copolymer films have a wide variety of nanosized microphase separation structures such as spheres, cylinders, and lamellae. As described in the above subsection, photofunctional chromophores were able to be doped site-selectively into the nanoscale microdomain structures of the diblock copolymer films, resulting in nanoscale surface morphological change of the doped films. The further modification of the nanostructures is useful for obtaining new functional materials. Hence, in order to create further surface morphological change of the nanoscale microdomain structures, dopant-induced laser ablation is applied to the site-selectively doped diblock polymer films. 

Figure 13.15 Schematic representation of synthesis and surface modification of nanoparticles [54]. (Reproduced with permission from W.J. Rieter et al., Surface modification and functionalization of nanoscale metal-organic frameworks for controlled release and luminescence sensing, Journal of the American Chemical Society, 129, 9852-9853, 2007. 2007 American Chemical Society.)...

Other exciting frontier areas of research in chemical engineering include molecular and nanoscale engineering, molecular simulation, surface modification, protein separation processes, supercritical fluid extraction, fluid particle systems, catalysis and reaction engineering, biochemical engineering, and computer-aided design, see also Careers in Chemistry. 

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