Aryl diazonium salts: a new class of coupling agents for bonding polymers, biomacromolecules and nanoparticles to surfaces

Abstract

This critical review summarizes existing knowledge on the use of diazonium salts as a new generation of surface modifiers and coupling agents for binding synthetic polymers, biomacromolecules, and nanoparticles to surfaces. Polymer grafts can be directly grown at surfaces through the so-called grafting from approaches based on several polymerization methods but can also be pre-formed in solution and then grafted to surfaces through grafting onto strategies including "click" reactions. Several routes are also described for binding biomacromolecules through aryl layers in view of developing biosensors and protein arrays, while the use of aryl diazonium coupling agents is extended to the attachment of nanoparticles. Patents and industrial applications of the surface chemistry of diazonium compounds are covered. This review stresses the paramount role of aryl diazonium coupling agents in adhesion, surface and materials sciences (114 references).

Tuning TiO2nanoparticle morphology in graphene–TiO2hybrids by graphene surface modification

“…GNP can reduce the diazonium cation to two different radicals (Scheme 1b), which are responsible for the GNP functionalization (Scheme 1c). [50][51][52][53] To synthesize NH 2 -GNP, carboxylic groups are activated with SOCl 2 , and converted into amides by reaction with ethylenediamine, leaving an unreacted NH 2 group at the end of the functional layer (Scheme 1d). 54 The C, O and N content in pristine and functionalized GNPs as measured by XPS are reported in Table 1.…”

Electrografting of calix[4]arenediazonium salts to form versatile robust platforms for spatially controlled surface functionalization

“…An alternative strategy for connecting organic moieties onto electrodes is the reductive grafting of aryldiazonium salts that yields covalent attachment of phenyl derivatives onto the surface. Electrografting in particular has gained tremendous interest over the last decade and is now a well-recognized method for surface functionalization [20][21][22][23][24] . Contrary to alkylthiol SAMs, the organic layers obtained from this method are generally highly stable, being strongly resistant to heat, chemical degradation and ultrasonication 20,25 .…”

The Electro-Photonic Silicon Biosensor

“…The combination of electrochemical and photonic measurements thus enables us to deduce that the subsequent electroreduction processes occurring in cycles 2-4 correspond to the formation of a multilayer structure at the electrode. Multilayers are often observed in diazonium electrografting 20 , and the mechanism of (d) Resonance dip of a doped device compared with that of a microring resonator of identical geometry but fabricated on undoped silicon, showing a moderate broadening due to the increase in optical loss. The resonance wavelengths were 1,580.2 and 1,580.17 nm for the undoped and doped substrates, respectively.…”