Molecular Simulation of the Fabrication and Permselective Characterisation of Thin Nanoporous Silica Films

1. Introduction A major field of ongoing study in gas mixture separation technology involves the development of novel composite ceramic membranes suitable for use across a broad range of process conditions. A common theme in these studies is the use of mesoporous/microporous support materials (e.g. α-alumina/γ-alumina, Vycor etc) with a minimum pore size of approximately 5 nm, in some cases supplemented with a further oxide microporous layer with pore dimensions of 1-3nm, upon which is deposited a silica layer containing subnanometer pores (see for example [1-4]). This layer is the selective coating which itself is typically 30-100 nm thick. While it is generally assumed that the transport process of the gas species within the selective layer is activated in nature, there are anomalies with this simplified picture and the work presented here represents a summary of recent work undertaken to clarify some of these issues.