Electrografting process

Figure 2. Schematic showing two-step electrografting process of OTS (R represents the CH3 group) monolayer on Si via formation of Si—Si bonds.

Extension of the Electrografting Process to Monomers Other than AN 908... 

A first sign of the formation of an organic layer on metallic surfaces by electrochemical reduction of aryl diazonium salts is the disappearance of the expected characteristic broad and irreversible cathodic wave observed by cyclic voltammetry upon an initial scan towards negative potentials. Such blocking effect of the electrochemical response was firstly pointed out by Parker and coworkers.The different steps that take place along the electrografting process were established later on 17,371 been demonstrated that the electron transfer concerted with the loss of... 

Vinylic compounds have been attached by electrochemical reduction to an important number of oxidizable materials such as Fe, Ni, Cu, Au, Pt or stainless steel, but also carbon, silicon, CdSe and Teflon." ° Most of metals can be covered with oxides which could be reduced by the application of negative potentials during the electrografting process. However, the possibility that the electrografting occurs also on oxidized sites cannot be ruled out. 

Fig. 4. Nanopatterning of alkynes using a conducting AFM tip for cathodic electrografting on H/Si(lll). The process is shown schematically at the left while representative line scans after electrografting with different alkynes are shown on the right. The observed heights in the AFM scans correlate well with the expected heights. Adapted from [39].

It is worth noting that the process is inefficient with secondary amines because steric hindrance limits the access of the nitrogen radical to the solid carbon surface and severely decreases the rate of grafting. As a consequence, the coverage for these compounds is very low as compared to primary amines. The absence of hydrogen in tertiary amines makes them unsuitable for electrografting. Furthermore, the increased stability of secondary and tertiary amine radical cations is another reason for the lack of grafting which is also the case for aromatic primary amines (aniline and its derivatives). 

The electrografting mechanism involves a nucleophilic attack of the alcohol on a radical cation formed at the carbon surface leading to the formation of an ether linkage (C-O-R) (Figure 10.4). Contrary to the previous examples, this process requires the electroactivation of the substrate rather than the solute. This technique is very effective in terms of coating adhesion and range of functionalities available on the surface but is restricted to glassy carbon substrates. 

Many applications of this process have been reported in the literature [11], one among them being the electrochemical detection of alkaline ions [12]. As mentioned above, the electrografting of 1-octanol on a carbon substrate prevents... 

The development of these bactericidal coatings is a representative example of how combining electrografting with more conventional controlled polymerization and deposition processes might be a powerful tool to confer long-term and specific surface properties to metals. 

Being a cathodic process, electrografting is an ideal coating process not only for noble metals, that is, metals that resist... 

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