Synthesis of water-dispersible, fluorinated particles with grafting sulfonate chains by the core crosslinking of block copolymer micelles

Fluorinated polymer particles with grafting sulfonate chains, which showed high dispersion stability in aqueous media, were synthesized by the crosslinking of block copolymer micelles. A crosslinkable block copolymer, poly[(2,3,4,5,6-pentafluorostyrene)-co-4-(1-methylsilacyclobutyl)styrenel-b-poly(neopentyl 4-styrenesulfonate), composed of a statistical copolymer segment of 2,3,4,5,6-pentafluorostyrene with 4-(1-methylsilacyclobutyl)styrene and a neopentyl 4-styrenesulfonate segment, was prepared by the nitroxy-mediated living radical polymerization of a 2,3,4,5,6-pentafluorostyrene/4-(1-methylsilacyclobutyl)styrene mixture and neopentyl 4-styrenesulfonate. The block copolymer formed micelles with a poly[(2,3,4,5,6-pentafluorostyrene)-co-4-(1-methylsilacyclobutyl)styrene] core in acetonitrile, which were crosslinked via the ring-opening reaction of silacyclobutyl groups in the core by a treatment with a platinum catalyst. The deprotection of sulfonate groups in the micelle corona by exposure to trimethylsilyl iodide and a treatment with aqueous HCl, followed by neutralization with aqueous NaOH, provided a polymer particle with polymer chains of sodium 4-styrenesulfonate grafted on its surface. (c) 2007 Wiley Periodicals, Inc.