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Oligo(ethylene glycol) methacrylate (OEGMA) was grafted from Au surface via surface-initiated atom-transfer radical polymerization (s-ATRP). The initiator density was adjusted by the mole fractions of surface-attachable ATRP initiator and diluting agent. Three OEGMA monomers of Mr 300, 475, and 1100 were used. The Au surfaces before and after modification were characterized by water contact angle and ellipsometry. The effect of monomer Mr and initiator density on surface chain density and EO unit density was investigated. It was found that at low initiator density (mole fraction of initiator of 2%-5%), poly(OEGMA) grafts had comparable surface chain density independent of OEGMA [M.sub.r]. However, at high initiator density (mole fraction of initiator >10%), poly(OEGMA)noo had obviously lower chain densities than [poly(OEGMA).sub.300] and [poly(OEGMA).sub.475], which could be attributed to the size difference of the monomers. The short chain length and low surface chain density of poly(OEGMA)1100 resulted in its relatively low surface EO unit density. Key words: Au surface, poly(ethylene glycol), atom transfer radical polymerization (ATRP), grafting, surface chain density, surface EO unit density, monomer Mr. On a greffe du methacrylate d'oligo(eethyleneglycol) (MAOEG) sur une surface d'or par le biais d'une polymerisation radicalaire par transfert d'atome initie par la surface (PRTA-s). La densite de l'initiateur a ete ajustee par les fractions molaires de l'initiateur de la PRTA qui peuvent etre attacheees a la surface et l'agent diluant. On a utilise trois MAOEG de [M.sub.r] 300, 475 et 1100. On a caracterise; les surfaces d'or avant et apres modification par l'angle de contact de l'eau et par ellipsomeetrie. On a etudie l'effet du poids moleeculaire du monomere et la densite de l'initiateur sur la densite; de la chaine en surface et sur la densite de l'unite d'oligoethyleneglycol. On a trouve que pour des densites d'initiateur faibles (fraction molaire d'initiateur allant de 2 % a 5 %), la densite de chaine en surface des greffes est independante du Mr du MAOEG. Toutefois, a des densites d'initiateur plus eleveees (fraction molaire d'initiateur supeerieure a 10 %), les densities de chaine du [poly(MAOEG).sub.1100] sont evidemment plus faibles que celles des [poly(MAOEG).sub.300] et [poly(MAOEG).sub.475] et cette situation peut etre attribueeea une difference dans la taille des monomeres. La courte longueur de la chaine et la faible densite de la chaine de surface du [poly(MAOEG).sub.1100] resultent de la densite relativement faible de l'unite d'oligoethyleneglycol. Mots-cles: surface d'or, poly(ethyleneglycol), polymerisation radicalaire par transfert d'atome (PRTA), greffage, densite de la chaine en surface, densite de l'unite d'oligoethyleneglycol, Mr du monomere. [Traduit par la Redaction], Introduction Poly(ethylene oxide) (PEO)- and oligo(ethylene glycol) (OEG)-containing polymers (e.g., poly(oligo(ethylene glycol) methacrylate) (poly(OEGMA))) have attracted much attention as a biomaterial coating because of its high ability to resist non-specific [...]

The adsorption of human serum albumin onto polystyrene (PS) and polymethylmethacrylate (PMMA) blend surface from five different pH solutions is studied using x-ray photoemission electron microscopy. Albumin exhibits completely extended (pH 2.0) and a completely contracted (pH 10.0) structures, but at the intermediate stages (pH 4.0) albumin opens some hydrophilic sites and shows preferential adsorption for hydrophilic PMMA.