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

In this study, amine-mediated silica aerogels dried under the ambient conditions in monolithic form were prepared by following sol-gel method. 3-aminopropyltriethoxysilane (APTES) was involved to the synthesis as a silica co-precursor. Imidazolium based short-chain ionic liquids (ILs) were incorporated into the silica gel structure to control the gel shrinkage within the pores, as well as to eliminate the capillary effect during the solvent evaporation. A production procedure was developed to explore the synergistic effect of ionic liquids and amine functionalized silica 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 reveal the chemical and morphological characteristics of the resultant material, various analyses were conducted.  SEM and FTIR analyses were performed to investigate the morphological and chemical structure, whereas TGA analysis was carried out to determine the thermal stability of the silica gels. As a result, ionic liquid embedded sample was obtained in a monolithic structure 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 hydrophobic characteristic with a water contact angle value of 113˚.