Nanostructure of polystyrene-b-poly(2-hydroxyethyl methacrylate) and derivatives with phosphonic diacid groups

Surface engineering for precise positioning of biomolecules is of particular interest for controlled fabrication of biochips. In this study, a novel approach for the preparation of nanodomains with phosphonic diacid groups that were previously shown to reversibly bind to a family of proteins (annexins) in a calcium-dependent manner is described. The strategy makes use of polystyrene-b-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) precursors prepared by atom transfer radical polymerization (ATRP) to obtain hexagonally packed PS cylinders (f(PS) = 0.25-0.27) in a PHEMA matrix. The pendant hydroxyl groups of PHEMA are then partially (ca. 20%) converted into phosphonic diacid groups via sequential reactions involving phosphorylation, silylation and methanolysis. This process produces PS-b-P(HEMA-co-PEMA) derivatives that still retain the hexagonal morphology, but their degree of structural organization is reduced comparatively to the precursors.