Three-dimensional titania pore structures produced by using a femtosecond laser pulse technique and a dip coating procedure

In this work, the preparation of three-dimensional hierarchical pore structures by a combination of laser-based templates and the self-organization process of mesostructured titania is presented. For this purpose macrostructured polymers produced by two-photon polymerization act as a template for the deposition of a mesostructured titania film from a solution containing an amphiphilic block copolymer by dip coating. A carefully applied calcination procedure removes both the macrotemplating polymer and the mesotemplating surfactant molecules so that a replica of the initial polymer structure with a hierarchical (macro- and meso-) pore system is obtained. In addition, the titania, which is amorphous after deposition, is transferred into crystalline anatase during calcination. Materials with dual pore systems are interesting for possible applications in catalysis and sorption, and three-dimensional crystalline structures from materials with high refraction index are attractive for photonic applications, for example as photonic crystals.