Preparation of γ-Al2O3 film by high temperature transformation of nanosized γ-AlOOH precursors

Mesoporous boehmite (gamma-AlOOH) and gamma-alumina (gamma-Al2O3) self-supported films were prepared by high temperature transformation of gamma-AlOOH precursor fibers. A polymer, sodium polyacrylate, was used as a size/ morphology controlling agent yielding to a stable colloidal suspension of boehmite ribbon-like fibers after a 168 h hydrothermal treatment at 160 degrees C. The slow evaporation of the solvent leads to gamma-AlOOH film without any cracks and pinholes. The gamma-Al2O3 film, obtained after calcination of the gamma-AlOOH film, exhibit a high thermal stability up to 1000 degrees C and two distinct kinds of mesopores with average diameters of 20-30 angstrom and 50 angstrom. Structural and textural properties of these films confer them interesting properties for filtration processes.