Direct Electrografting of Poly(2-alkyl-2-oxazoline)s on Gold, ITO, and Gold Nanoparticles for Biopassivation

Poly(2-alkyl-2-oxazoline)s (POx) bearing an aminophenyl end group were synthesized by cationic ring-opening polymerization; the polymers were then carefully characterized by NMR, size exclusion chromatography, and differential scanning nano calorimetry. The electroreduction of the diazonium salts of aniline terminated poly(2-methyl-2-oxazoline) (PMeOx) and poly(2- n -propyl-2-oxazoline) (P n PrOx) from aqueous solution on indium tin oxide (ITO) and gold (Au) and through a two-dimensional polystyrene (PS) template has been investigated. On all substrates, ultrathin layers of polymer are grafted and deposited. Modified surfaces were characterized by electrochemistry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy. Nanoporous honeycomb POx structures have been obtained thanks to electrochemical growth in the interstitial spaces between self-assembled PS spheres. Finally, the wettability of the surfaces depends markedly on the chemical nature of the POx, with contact angles of 32° and 70° for modified surfaces with PMeOx and P n PrOx.