Protein-resistance performance of amphiphilic copolymer brushes consisting of fluorinated polymers and polyacrylamide grafted from silicon surfaces

A series of random copolymer brushes of acrylamide (AM) and 2-(perfluorinated hexyl)ethyl methacrylate (FMA) were grafted from initiator-functionalized silicon wafers by surface-initiated atom transfer radical polymerization. The water contact angle, X-ray photoelectron spectroscopy and atomic force microscopy were used to characterize surface wettability, surface composition, and morphology of the surfaces modified with polymer brushes, respectively. The protein-resistance performance of the surfaces grafted with polymer brushes was evaluated using micro-BCA protein assay reagent. It was found that the random copolymer brushes with the optimal ratio of AM to FMA in monomers showed the best protein-resistance performance, however, the optimal ratio is different for resisting bovine serum albumin and human plasma fibrinogen adsorption. For resisting bovine serum albumin adsorption, the optimal ratio of AM to FMA in monomers is 1 : 3, while the optimal is 3 : 1 for human plasma fibrinogen adsorption resistance. The results provide further evidence that surface compositional heterogeneities and microphase segregation of fluorinated moieties of amphiphilic random copolymer brushes significantly impact protein adsorption behaviors.