Cathodic electrografting

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].

In this article, we demonstrate cathodic electrografting of two different molecules on Si—H substrates (i) a a-molecule of short chain length. octyltrichlorosilane (CH3-(CH2)7-SiCl3 OTS) and (ii) a new a-Jl molecular rectifier. 5-(4-undecenyloxyphenyl)-10,15,20-triphenylporphyrin(2) (TPP-C11). 

Robins EG, Stewart MP, Buriak JM (1999) Anodic and cathodic electrografting of alkynes on porous silicon. Chem Commun 24 2479-2480... 

The group of Buriak (Stewart and Buriak 1998,2001 Buriak and Allen 1998b Buriak 1999 Robins et al. 1999 Buriak et al. 1999 Holland et al. 1999) introduced three different approaches to obtain the chemically derivatized PSi surface Lewis acid-mediated hydrosilylation, white light-promoted hydrosilylation, and cathodic electrografting. The highest treatment efficiency (the proportion of replaced Si-Hjc) of 28 % was obtained with one pentene using Lewis acid-mediated hydrosilylation (Stewart et al. 2000). Boukherroub et al. (2001) extended the usable techniques for hydrosilylation by introducing... 

In addition, if the cathodic electrografting of diazonium compounds onto carbon substrates (glassy carbon, HOPG, carbon fibers, carbon nanotubes [16], carbon felts... 

So, the best guideline for the cathodic electrografting of vinyl monomers to be successful is a scale of donidty of monomers and organic solvents stable in the cathodic regime. However,... 

Although electrooxidation of heteroaromatic monomers, such as pyrrole, thiophene, and their derivatives, is a classical technique to prepare intrinsically conducting polymer, a drawback of this method is the poor adhesion of the films to the substrate. The polymer chains are indeed merely deposited by precipitation on the electrode without creating specific mutual interactions. A way of tackling this problem is to combine anodic electropolymerization with cathodic electrografting. 

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

In close relation to the molecular stmcture, the amphiphi-lidty of the monomer is of prime importance. On the basis of voltammetric and ellipsometric data, a three-step mechanism was proposed to explain the successful electrografting. The positively charged micelles formed by the monomer in water diffuse toward the cathode and spread out on the solid surface as a bilayer. At an appropriate cathodic potential, the acrylic double bonds of the double layer, which are close enough to... 

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