Facile synthesis of large-sized monolithic methyltrimethoxysilane-based silica aerogel via ambient pressure drying

Abstract

In this study, large-sized monolithic methyltrimethoxysilane-based silica aerogels were prepared via a facile sol–gel route using ambient pressure drying. The structural, morphological, and hydrophobic properties of the aerogels were characterized by scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller method, and contact angle. Thermal conductivity, thermal stability, and mechanical properties of the samples were also evaluated. The ambient pressure dried aerogels showed macro-pore structure and low density (as low as 75 kg m−3). The Young’s modulus of the aerogels was observed to increase from 0.043 to 1.102 MPa with an increase in the density of the aerogels from 75 to 141 kg m−3. Simultaneously, the aerogels exhibited superhydrophobicity (>150°), low thermal conductivity (0.036 W m−1 K−1), and good thermal stability in air atmosphere. Both the simple fabricating process and the superior performance of the monolithic silica aerogel make it as a promising candidate for energy-saving sector. Large-sized monolithic methyltrimethoxysilane-based silica aerogel with superhydrophobicity was successfully prepared by a one-step sol–gel method via ambient pressure drying using methyltrimethoxysilane as precursor, distilled water as solvent, and ammonia as alkali catalyst.