The influence of TiO2 as inorganic filler in poly(vinylidene fluoride) (PVDF) and polyamideimide (PAT) membranes on various permeation processes has been investigated. PAI/TiO2 Membranes could be prepared without any post-treatment. Furthermore, PAT membranes with 40wt.%, TiO2 could withstand a temperature treatment at 180degreesC with only minor decrease in fluxes. The pore size distribution of the thus treated membranes remained practically unchanged. PVDF/TiO2 membranes were clearly less susceptible to compaction than pure PVDF membranes during pressure treatment at 30 bar. Additionally, hydrophilic composite membranes with either PVDF or PVDF/TiO2 supports were tested in vapour permeation experiments for the dehydration of ethanol. The tests covering a temperature range from 78 degreesC (1 bar) to 135 degreesC (6.5 bar) revealed that the membranes with the organic-inorganic support showed significantly better permeate quality even at 135 degreesC accompanied by higher fluxes within the investigated temperature range. (C) 2004 Elsevier B.V. All rights reserved.