Critical Domain Sizes of Heterogeneous Nanopattern Surfaces with Optimal Protein Resistance

To investigate protein-resistant surfaces with heterogeneous nanopatterns, V-shaped polymer brushes composed of a hydrophilic methoxypoly(ethylene glycol) (mPEG) arm and a hydrophobic polystyrene (PS) or fluorinated poly(methyl methacrylate) (PMMA-b-PFMA) arm were prepared, in which the surface structure and phase-separation behavior were controlled by altering the relative lengths of the two arms. The protein resistance of these amphiphilic brushes was better than that of pure poly(ethylene glycol) (PEG) brushes, and when the domain size of the phase-separated structures was about twice the size of the protein molecules, the surfaces exhibited optimal protein repellence. At the same time, the amount of protein adsorption was well related to both the adhesion and the relative friction coefficient of the protein on the brush surface. A heterogeneous surface with phase-separated domains twice the size of protein molecules may be beneficial for minimizing protein adsorption through the synergistic effect of hydrophobic and water-soluble domains. These results provide an important way for designing and preparing protein-resistant materials with heterogeneous surfaces.