Template-Directed Synthesis of Hybrid Titania Nanowires within Core−Shell Bishydrophilic Cylindrical Polymer Brushes

Abstract

Well-defined core−shell bishydrophilic cylindrical polymer brushes (CPBs) with a poly(2-hydroxyethyl methacrylate) (PHEMA) core and a poly(oligo(ethylene glycol) methacrylate) (POEGMA) shell were synthesized via the combination of anionic polymerization and atom transfer radical polymerization. They were used as a unimolecular cylindrical template for the controlled fabrication of linear assemblies of titania nanoparticles. The titania precursors were found localized mainly in the brush core via a transalcoholysis reaction and partially in the shell via a weak complexation force. After hydrolysis, the obtained titania−CPB hybrid nanowires are amorphous and soluble in organic solvents as well as water. A phase transition from amorphous titania to anatase titania was found by refluxing the hybrid nanowire solution for 5 days in a mixture of water/dioxane (vol. ratio = 1/3). They could also serve as in situ template for the pyrolytic formation of inorganic crystalline titania nanowires at 550 °C.