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) (PnPrOx) 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 degrees and 70 degrees for modified surfaces with PMeOx and PnPrOx.