title: Synthesis of iron oxide rods coated with polymer brushes and control of their assembly in thin films.
abstract: We investigated the surface-initiated atom transfer radical polymerization (SI-ATRP) of methyl methacrylate (MMA) using monodisperse rod-type particles of iron oxide, β-FeOOH. The slow hydrolysis of iron(III) chloride yielded monodisperse β-FeOOH rods with an average length-to-width ratio, L/W, of 6 (L = 210 nm and W = 35 nm on average). The surfaces of the β-FeOOH rods were modified with a triethoxysilane derivative as an ATRP-initiating site, namely, (2-bromo-2-methyl)propionyloxypropyl triethoxysilane. The SI-ATRP of MMA, mediated by a copper complex, was performed using the initiator-coated β-FeOOH rods in the presence of a "sacrificial" free initiator. Well-defined poly(methyl methacrylate) (PMMA) brushes with molecular weights of up to 700,000 could be grafted on the β-FeOOH rods with a surface density as high as 0.3 chains/nm(2). The resultant polymer-brush-afforded hybrid rods exhibited high dispersibility in various solvents for PMMA without forming aggregates. Thin films were prepared by dip-coating from a suspension of the hybrid rods, and the rods were oriented in a specific direction in the films. The arrangement of the rods could be controlled by varying the chain length of the polymer brush and the withdrawal speed during the dip-coating process.
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.forename: Ryohei
authors.initials: R
authors.lastname: Ishige
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Tsujii
authors.forename: Kohji
authors.initials: K
authors.lastname: Ohno
mesh_terms: D002712:Chlorides / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D006868:Hydrolysis; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D012821:Silanes; D012997:Solvents; C000499:ferric oxide; D019904:Polymethyl Methacrylate; C024555:ferric chloride