Diazonium salts for surface-confined visible light radical photopolymerization

Abstract

The surface chemistry of aryl diazonium salts has progressed at a remarkable pace in the last two decades, and opened many avenues in materials science. These compounds are excellent coupling agents for polymers to surfaces via several surface‐confined polymerization methods. For the first time, we demonstrate that diazonium salts are efficient for surface initiating radical photopolymerization in the visible light of methyl methacrylate (MMA) and 2‐hydroxyethyl methacrylate (HEMA) taken as model monomers. To do so, 4‐(dimethylamino)benzenediazonium salt was electroreduced on gold plates or flexible ITO sheets to provide 4‐(dimethylamino)phenyl (DMA) hydrogen donor layers; while excited state camphorquinone acted as the free hydrogen abstractor. In the same way, we co‐polymerized HEMA and MMA with ethylene glycol dimethacrylate in order to obtain crosslinked polymer grafts. We demonstrate by XPS that gold was efficiently screened by the polymer layers and that the wettability of the surfaces accounts for the hydrophilic or hydrophobic characters of the tethered polymers. Homo‐ and crosslinked PMMA grafts were found to resist removal by the paint stripper methyl ethyl ketone. The grafted DMA/camphorquinone system operating in the visible light holds great promises in terms of adhesion of in situ designed continuous or patterned polymer coatings on various substrates. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3506–3515

Carbon black modified with 4‐hydroxymethylbenzenediazonium salt as filler for phenol‐formaldehyde resins and abrasive tools

“…On the surface of modified CB, the number of hydroxymethyl moieties increases, which is also clearly evidenced by the band at 532.4 eV (Figure , Table ) . An increase in the number of carboxylic groups was also observed, which was previously noted on the basis of FTIR analysis (Figure ).…”

Diazonium Salts: Versatile Molecular Glues for Sticking Conductive Polymers to Flexible Electrodes

“…In addition, diazonium compounds are versatile as they impart functionalities to the materials surfaces depending on the nature of the substituent borne by the benzene ring in either para-, metaor orthoposition of the diazonium group. In this way, one can design new surfaces possessing a plethora of properties such as hydrophilic/hydrophobic character [31], electrocatalytic activity [32], initiation of surface radical or oxidative polymerization [33][34][35], resistance to biofouling [36], sensing [37,38], reactivity towards polymer matrices [39,40].…”

Facile Synthesis of Tuneable Azophosphonium Salts

“…Synthesis of p ‐Aminobenzenediazonium Tetrafluoroborate [ p ‐H 2 N‐PhN 2 ][BF 4 ]: [ p ‐H 2 N‐PhN 2 ][BF 4 ] was prepared according to a modified literature procedure of Y. Yagci et al under inert conditions. 50 wt.‐% HBF 4 (0.97 mL, 7.7 mmol, 1.1 equiv) was added to a solution of p ‐phenylenediamine (759.3 mg, 7.0 mmol, 1.0 equiv) in acetone (10 mL) at 0 °C and a colour change from light pink to green/yellow was observed.…”