Effect of a Tetraethoxysilane Hydrolysis Reaction Catalyst on the Precipitation of Hydrolysis Products in the Pores of a Polyimide Track Membrane

Abstract

This paper presents the results of obtaining a composite film based on polyimide track membranes filled with a silica filler, although the issue of the deposition of this filler in the pores of the given membranes remained unexplored. The filler was obtained by hydrolysis of tetraethoxysilane using an alkaline and acid catalyst. This paper presents the results of the effect of the tetraethoxysilane hydrolysis reaction catalyst on the precipitation of hydrolysis products in the pores of the polyimide track membrane. The factors influencing the formation of silicon oxide nanofibers within the matrix template (polyimide track membrane) are determined. It was found that the use of an acid catalyst provides the highest rates of filling, while when using an alkaline catalyst, the filling is practically not observed, and only single pores are filled. The properties of the composite film obtained were investigated. SEM images of the surface and chip of the composite while using alkaline and acid catalyst are presented. The spatial structure of composite films based on track membranes was investigated by FTIR spectroscopy. The hydrolysis of tetraethoxysilane in an acid medium significantly decreases the optical density index of the membranes and simultaneously increases their light transmission index. The greatest changes are observed in the range of 500–1000 nm, and there are no detectable changes in the range of 340–500 nm. When using an alkaline catalyst, there is not the same significant decrease in the relative optical density index D.