EFFECT of IONIC LIQUID CONTENT on the MONOLITHIC STRUCTURE of AMINE-MEDIATED SILICA AEROGEL via AMBIENT PRESSURE DRYING

Abstract

In this study, amine-mediated silica aerogels dried under the ambient conditions inmonolithic form were prepared by following sol-gel method. 3-aminopropyltriethoxysilane(APTES) was involved in the synthesis as a silica co-precursor. Imidazolium-based short-chainionic liquids (ILs) were incorporated into the silica gel structure to control the gel shrinkagewithin the pores, as well as to eliminate the capillary effect during the solvent evaporation. Aproduction procedure was developed to explore the synergistic effect of ionic liquids and aminefunctionalizedsilica precursor on the textural and chemical properties of the final silica gels.Surface modifications of the samples were performed by using 3-Methacryloxypropyltrimethoxysilane (MEMO) to ensure hydrophobic characteristics. To revealthe chemical and morphological characteristics of the resultant material, various analyses wereconducted. SEM and FTIR analyses were performed to investigate the morphological andchemical structure, whereas TGA analysis was carried out to determine the thermal stability ofthe silica gels. As a result, the ionic liquid embedded sample was obtained in a monolithicstructure with a low density (0.45 g/cm3) and had a good thermal stability (up to 381 °C).Contact angle measurement also demonstrated that the desired monolithic sample has ahydrophobic characteristic with a water contact angle value of 113°.