Investigation of the preparation pH value influence on the single step silica Aerogel monolith porosity

Abstract

The influence of acidic and basic environment of sol on the final Aerogel properties was studied in this work. Transparency of silica Aerogel monolith was investigated according to their initial preparation pH values. The findings show that silica Aerogels’ optical transmittance is highly sensitive to the pH values employed in their production. Specifically, the silica Aerogels prepared at a pH of 8 demonstrate the highest level of transmittance. SEM as well as BET measurements of silica Aerogels are employed as pore structure probes to ascertain the changes, that occur in a TEOS precursor silica gel, as a function of the variation of the initial preparation pH value. There is a systematic correlation between sol acidic/ basic environment variation and Aerogel surface area except around pH 2 which exhibits abnormal results. While the relation between porosity as well as pore size and preparation pH values were more irregular.