Membrane growth of nanoporous silicates via the self-assembly monolayer.

The self-assembly monolayer (SAM) method was used for membrane fabrication, in which Si wafers were treated separately with N-trimethoxysilylpropyl-n,n,n-tri-n-butylammonium bromide (TMSP-TBA) and N-trimethoxysilylpropyl-n,n,n-trimethylammonium chloride (TMSP-TMA) to form monolayers on the Si surfaces. To grow silicate membranes on the organosilyl-treated Si wafers, a series of silicate sols were prepared with composites of tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicate sources, and tetrapropylammonium bromide (TPABr) was used as an organic template. Their microstructures were investigated in detail by comparing them using SEM and XRD.