Synthesis of arrayed, TiO2 needlelike nanostructures via a polystyrene-block-poly(4-vinylpyridine) diblock copolymer template

Arrayed, needlelike nanostructures of rutile phase crystal TiO2 were grown on a Si substrate containing TiO2 seeds prepared through a thin polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer template. The morphology of the deposited TiO2 nanostructures was characterized by field-emission scanning electron microscopy, X-ray diffraction, and transmission electron microscopy (TEM). By using TiO2 seeds prepared from their diblock copolymer PS-b-P4VP template, we fabricated arrayed, needlelike rutile TiO2 nanostructures with variable spatial positions and densities. The distance between two TiO2 needle bunches (120 and 160 nm) could be controlled using block copolymer templates with different molecular weights.