Asymmetric ceramic membranes from Langmuir-Blodgett deposition precursors:deposition of fatty acid salts on porous ceramic substrates

Nanoporous 7930 Vycor silica tubes and mesoporous and macroporous Anopore a nodic alumina discs are examined as substrates for the multilayer Langmuir- Blodgett (LB) deposition of Cd, Mg, Zn and Ca salts of the arachidic and st earic fatty acids. Conditions for successful deposition are reported. Under appropriate conditions both mesoporous and macroporous Anopore aluminas al low for a full substrate coverage (maximum degree of deposition, D-d,D-max --> 1), while a Vycor substrate imposes a D-d,D-max less than or equal to 0 .7 and a mechanism explaining the observed D-d,D-max values is presented. T he produced ceramic oxide-LB film composites are prototype precursors for g as-separating all-ceramic asymmetric membranes, following the application o f an oxidative plasma treatment. (C) 2000 Elsevier Science Ltd. All rights reserved.