Characterization and Transport Properties of Surfactant-Templated Silica Layers for Membrane Applications

Abstract

An intermediate surfactant-templated silica (STS) layer is applied between the supporting mesoporous γ -Al 2 O 3 and the amorphous microporous silica overlayer resulting in dual-layered microporous silica membranes for gas separation applications that show improved values for both hydrogen flux and selectivity. Determination of thickness and porosity of as-deposited membrane layers by spectroscopic ellipsometry reveals that the STS layer is present as a distinctive layer of ∼20 nm thickness, with penetration up to a depth of ∼70 nm into the underlying γ -Al 2 O 3 support layer, whose thickness and porosity are determined to be 1.3 µm and 50%, respectively.