Oriented zeolite MFI monolayer films on metal substrates by in situ crystallization

Continuous b-oriented zeolite MFI monolayer films (<0.4 pm thick) were prep ared by in situ crystallization on metal substrates (stainless steel and al uminum alloy) using a synthesis solution 0.32TPAOH:TEOS:165H(2)O (TPAOH: te tra-propylammonium hydroxide, TEOS: tetraethylorthosilicate). Effects of cr ystallization temperature and time, surface roughness, position and chemica l nature of the substrate, and aging time of the synthesis solution were in vestigated and a mechanism for the b-oriented monolayer thin film formation was discussed. The supported films were characterized with scanning electr on microscopy and X-ray diffraction. Polishing of the film with a normal la b polisher leads to a continuous ultrathin zeolite film with a surface roug hness less than 0.05 mum. (C) 2001 Elsevier Science B.V. All rights reserve d.