Multilayer Multifunctional Mesoporous Metal Oxide thin films made by integrative templating and etching methods

GALO J. A. A. SOLER-ILLIA; PAULA C. ANGELOMÉ; M. CECILIA FUERTES

Conferencia; European Materials Research Society Spring Meeting; 2005

In the last decade, a sound library of synthesis protocols for materials with tailored porosity and function has been developed. Integrative synthesis methods should allow to combine nanoscopic matter in composites where spatial separation of regions with different chemical properties is possible, leading to advances in integrated chemical sensors, preconcentrators and bionanomaterials. In this work, we produce multilayer thin oxide films by EISA methods, combining mesoscale (surfactants) and micron scale (PEO-based polymers) templates. A variety of mesoporous oxide frameworks (cubic or hexagonal silica, titania, zirconia or mixed oxides) can be synthesized, which can include one or several different organic or biological functions (alkyl, amino, thiol, aminoacid…) attached to the pore surface. Organic functions are added by co-condensation or post-grafting. Macroporous titania layers present distinct nested porosities in the 100 nm–4µm, and in the 2-4 nm ranges; post grafting of functional phosphates or phosphonates allow to functionalise these pores. Successive dip-coating/stabilization cycles combined with template extraction/functionalisation permit to create multilayered thin films presenting tailored porosity in the z axis. The film mesostructure can be affected by the mesostructure of the film situated beneath. A clever choice of the framework (Si, Ti, Zr, V, and mixed oxides) permits to selectively attach organic functions to any preselected layer, by making use of the different surface chemistry features. A variety of optical and transport characteristics can be achieved by selectively etching a determined layer.