Porous and worm-like titanium dioxide nanostructures from PS-b-PEO block copolymer micellar solutions

Mixed micellar systems containing polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymers and TiO2 nanoparticles in a solvent/non-solvent pair were prepared and used as scaffolds in order to obtain nanostructured titania films. The inorganic content was varied in a wide range of compositions, focusing on micellar systems with PS cores and PEO/TiO2 coronas. The spherical-to-cylindrical micelle transition was achieved by adding a small amount of homopolymer of the same nature of the core-forming block. Thin PS-b-PEO/TiO2 hybrid films with different morphologies were prepared by spin coating micellar solutions and were transformed into the corresponding titania films by thermal treatments. The degradation of the polymer template and the simultaneous crystallization of titanium dioxide were carried out without collapsing of the nanostructures. As a final result porous and worm-like nanostructured titania films were obtained.