Hydrothermal synthesis of boehmite on alumina membranes for superhydrophobic surfaces

Boehmite (gamma-AlOOH) coatings with nanoflakes and flower-like structures have been successfully synthesised on alumina membrane surfaces by hydrothermal reaction. The effects of hydrothermal reaction time and temperature on the morphologies of the layers were investigated. During the hydrothermal reaction, gamma-AlOOH nanoflakes grew randomly on the Al2O3 particles, which changed the surface morphology of the alumina membrane and promoted its roughness. X-ray powder diffraction and field emission scanning electron microscope were used to characterise the structure and morphology of the membranes. Contact angle measurements were used to analyse the wetting property of the alumina membrane surface. Alumina membranes coated with boehmite layers possessed the wetting property from superhydrophilic to superhydrophobic after chemical vapour deposition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane.