Hybrid organic/inorganic nanostructured systems obtained by self-assembly of block-copolymers

An amphiphilic polystyrene-b-poly(ethylene-oxide) (PS-b-PEO) diblock copolymer (BCP) was used as template for the incorporation of metal oxide nanoparticles, namely TiO2 or Nb2O5 using the sol-gel method. This study was aimed to the preparation of neat BCP and hybrid thin films by spin-coating. The hydrophilic sol†"gel precursor of the metal oxides was selectively incorporated into hydrophilic PEO domains of BCP organized in a hexagonal array of vertical cylinders embedded in the PS matrix. Removal of polymer matrix by heat-treatment produced a nearly periodic array of TiO2 or Nb2O5 nanoparticles reminiscent of original hexagonal nanostructure. A novel solvent annealing procedure was developed in order to improve the morphological order of the neat copolymer and of the hybrid materials. BCP/TiO2 hybrid and heat treated thin films were used as conductometric sensors to detect soot nanoparticles (PM 0.1 and 0.01).