Surface modification electronic mechanisms

Many applications of surface modified maferials (such as in molecular electronics, separation science or continuous flow catalysis) require the use of mechanically and pressure-stable carriers. Grubbs et al. and later Nuzzo et al. reported on the surface modification of Si(lll). Conversion of surface Si - H into Si-allyl groups allowed them to pursue the grafting-from approach shown in Schemes [36,37]. The thickness of the polymer layer could be... 

Bhowmick and co-workers [168] investigated the bulk and surface modification of ethylene propylene diene monomer (EPDM) rubber and fluoro-elastomer by electron beam irradiation. The structure of the modified elastomers was analysed with the help of IR spectroscopy and XPS. The gel content, surface energy, friction coefficient and dynamic mechanical properties of bulk modified fluoro-elastomers and the surface-modified EPDMs were also measured. The resultant properties of the modified EPDM were correlated with the structural alterations. 

Hemoproteins are a broad class of redox-proteins that act as cofactors, e.g. cytochrome c, or as biocatalysts, e.g. peroxidases. Direct ET between peroxidases such as horseradish peroxidase, lactoperoxidase," or chloropcroxidasc"" and electrode surfaces, mainly carbonaceous materials, were extensively studied. The mechanistic aspects related with the immobilized peroxidases on electrode surfaces and their utilization in developing biosensor devices were reviewed in detail. The direct electrical contact of peroxidases with electrodes was attributed to the location of the heme site at the exterior of the protein that yields close contact with the electrode surface even though the biocatalyst is randomly deposited on the electrode. For example, it was reported " that non-oriented randomly deposited horseradish peroxidase on a graphite electrode resulted in 40-50% of the adsorbed biocatalyst in an electrically contacted configuration. For other hemoproteins such as cytochrome c it was found that the surface modification of the electrodes with promoter units such as pyridine units induced the binding of the hemoproteins in an orientation that facilitated direct electron transfer. By this method, the promoter sites induce a binding-ET process-desorption mechanism at the modified electrode. Alternatively, the site-specific covalent attachment of hemoproteins such as cytochrome c resulted in the orientation of the protein on the electrode surfaces and direct ET communication. ... 

When electrical and electronic properties are also of interest apart from mechanical and thermal properties, carbon nanotubes can be of better advantages. Nanotubes are inert in nature and, therefore, also require surface modification in order to achieve compatibility with the polymer matrices. Thus, the nanoscale dispersion of the nanotubes is as important and challenging as the layered silicates as the properties are dependant on the generated morphology in the composites. In a representative study, Teng et al. 

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