jp066811s_si_001.pdf (1.44 MB)
Functionalization of Titanium Oxide Surfaces by Means of Poly(alkyl-phosphonates)
journal contribution
posted on 2006-12-28, 00:00 authored by V. Zoulalian, S. Monge, S. Zürcher, M. Textor, J. J. Robin, S. TosattiThe 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.