The effect of thermal and vapor annealing treatments on the self-assembly of TiO2/PS-b-PMMA nanocomposites generated via the sol-gel process

Polystyrene-block-poly(methyl methacrylate) (SMMA) block copolymer has been used as a structure-directing agent for generating TiO2/SMMA nanocomposites via the sol-gel process using a hydrophobic surfactant. The aim of the work has been focused on the preparation of well-defined nanostructured composites based on the self-assembling capability of the block copolymer using two different annealing methods: thermal-and solvent-induced microphase separation. The addition of different amounts of nanoparticles caused strong variations in the self-assembled morphology of the TiO2/SMMA nanocomposites with respect to the block copolymer, as observed by atomic force microscopy (AFM). To verify the confinement of the nanoparticles in the PMMA block 3D AFM images and corresponding AFM profiles have also been reported. UV light irradiation of the nanocomposite films provoked the removal of the organic matrix and consequently led to an array of TiO2 nanoparticles on the substrate surface.