Inorganic monolayers formed at an organic template: A Langmuir-Blodgette route to monolayer and multilayer films of zirconium ocadecylphosphonate

Single-layer and multilayer films of zirconium octadecylphosphonate have been prepared on silicon oxide surfaces and characterized by Langmuir-Blodgett (LB) transfer data, contact angle, ATR-FTIR, XPS, ellipsometry and X-ray diffraction. The deposition method uses a preformed, organized organic template for assembling the inorganic lattice by combining LB and self-assembly (SA) techniques. First, an LB template of octadecylphosphonic acid is formed on an octadecyltrichlorosilane-covered substrate, then Zr[sup 4+] ions are [open quotes]self-assembled[close quotes] from solution. A capping octadecylphosphonic acid LB monolayer is added to complete the bilayer. Transfer of the phosphonic acid is continuous with transfer ratios ranging between 1.1 and 1.2. Contact angle measurements on a completed bilayer give an advancing contact angle of 112 [plus minus] 1[degrees]. The asymmetric methylene (v[sub a](CH[sub 2])) band remains unchanged in the progression from the template layer to bilayer to multilayers. XPS analysis of the zirconated LB template shows a 1:1 ratio Zr:P, while bilayer and multilayer films possess a Zr:P ratio of 1:2 consistent with the stoichiometry observed in solid zirconium phosphonate. Ellipsometry shows a layer-by-layer increase in film thickness corresponding to a bilayer thickness of 51 [angstrom], while X-ray diffraction reveals a d spacing 52 [angstrom] and thus demonstrates the layered nature of the films. The zirconium phosphonate films are quite insoluble in both water and organic solvents. 51 refs., 8 figs.