From Hybrid Films to Mesoorganized Multi-metal-oxide Nanocrystalline Films (M3NF), preparation and characterization.

Abstract

ABSTRACTHigh quality and reproducible thin silica and non-silica mesoporous films were obtained with mono-oriented organised mesoporosity, fitting various symmetry groups (i.e. p6m, Pm3n, Im3m, …). The Evaporation Induced Self Assembly (EISA) mechanism of structuration was studied through in-situ time-resolved SAXS, interferometry and spectroscopic ellipsometry investigations during dip-coating. A Modulable Steady State (MSS) was found during which the system is in quasi-equilibrium with its environment and during which the final structure is formed. The corresponding Self-Assembly mechanism was found to be governed by a competition between evaporation, micellization and condensation that depend on various critical chemical and processing parameters the influence of which have been summarized into directly usable phase diagrams. Calcined SiO2 and TiO2 mesoporous films structure (pore size and anisotropy, porous volume and surface) and mechanical properties (young modulus) were investigated by UV-Visible spectroscopic ellipsometry. Finally, thanks to a specially designed block copolymer, one further step was accomplished by achieving the dip coating and controlled nano-crystallisation of various metallic and multi-metal-oxides films (M3NF) of composition CoxTi(1-x)O(2-x) with ilmenite or doped Anatase structure, and SrTiO3 and MgTa2O6 with perovskite structure. Attending the well known magnetic, dielectric and catalytic properties of these structures, M3NF are highly compatible with high technology applications in microelectronic, energy transfer devices, spintronic, nano-mechanical adjustments, data storage, oxide fuel cells …