10.1021/jp066811s.s001 V. Zoulalian V. Zoulalian S. Monge S. Monge S. Zürcher S. Zürcher M. Textor M. Textor J. J. Robin J. J. Robin S. Tosatti S. Tosatti Functionalization of Titanium Oxide Surfaces by Means of Poly(alkyl-phosphonates) American Chemical Society 2006 stability attachment sites strategy XPS PEG side chains methacrylate angle spectroscopic ellipsometry titanium oxide surfaces Titanium Oxide Surfaces pH serum adlayer exposure protein adsorption monomer 2006-12-28 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Functionalization_of_Titanium_Oxide_Surfaces_by_Means_of_Poly_alkyl_phosphonates_/3037564 The use of a multiple attachment sites strategy is considered in order to improve the stability of monomolecular adlayers. The hypothesis was tested in the case of PEG-ylated compounds carrying phosphonate groups, known for their affinity toward titanium oxide surfaces. As a result, a new class of co- and terpolymers were synthesized by free-radical polymerization of three different monomers:  dialkyl(methacryloyloxyalkyl)phosphonates, PEG methyl ether methacrylate, and/or butyl methacrylate monomers. Adlayers were formed following a simple dip-and-rinse protocol using diluted aqueous polymer solutions and were characterized by evaluating their thicknesses with variable angle spectroscopic ellipsometry (VASE) and their elemental compositions with X-ray photoelectron spectroscopy (XPS). The same techniques were used to determine changes of the adlayer as a function of exposure to electrolytes at different pH values and to monitor nonspecific protein adsorption upon serum exposures. The results indicated that the poly(alkyl-phosphonate)-based adlayers combine multiple site attachment of phosphonic groups and presentation of PEG side chains to the aqueous environment, resulting in both improved stability over a wide pH range in comparison to the tested reference surfaces and excellent resistance to protein adsorption when exposed to full human serum.