Protein-resistance performance enhanced by formation of highly-ordered perfluorinated alkyls on fluorinated polymer surfaces.

In this paper, the relationship between the surface structure of fluorinated polymers and their protein-resistant property was studied by preparing films of poly(n-alkyl methacrylate) end-capped with 2-perfluorooctylethyl methacrylate (FMA) (PFMA(y)-ec-PnAMA(x)-ec-PFMA(y)) with various ordered structures of perfluorinated alkyls. These fluorinated polymers were synthesized via a controlled/living atom-transfer radical polymerization (ATRP) method. Both the surface free energy and the CF(3)/CF(2) ratio obtained by X-ray photoelectron spectroscopy (XPS) were employed to scale the ordered structures of the perfluorinated alkyls. Protein adsorption studies using fibrinogen as a test molecule were undertaken on the various films by XPS. The results show that the adsorbed mass of fibrinogen decreased linearly with increasing CF(3)/CF(2) ratio on the fluorinated polymer surfaces. When the CF(3)/CF(2) ratio reaches 0.26, there was almost no fibrinogen adsorption. This work not only demonstrates the design of a fluorinated copolymer film on glass substrate with desirable protein-resistant performance, but also provides a fundamental understanding of how the orientation of perfluoroalkyl side chains affects protein-resistant behavior on fluorinated surfaces.