One pot rapid synthesis of ultra high strength hydrophobic bulk silica aerogels

Abstract

Aerogels are currently known as ultra-light porous materials with very low density, which enables many potential applications, from ultra-light insulation to new energy materials. Currently, the limitations of expensive synthesis methods and fragile structure support are seriously hampering their application; these are the most prominent problems for aerogel materials. To boost the structural tunability of the aerogel pore structure, we adopted methyltrimethoxy silane (MTMS) as a precursor and used a highly mature and homogeneous filling to synthesize a high strength silica aerogel with multiple network construction. This new method, phrased as “neck-strengthening effect induced by high polycondensation reaction”, avoided the processes of organic solvent replacement and the intervention of highly polluting modifiers. This synthesis strategy greatly simplifies the fabrication process of silica aerogels. Also, it is worth mentioning that the prepared silica aerogels have high compressive strength up to 14.42 MPa and bulk density of 0.32 g cm⁻³, which is two orders of magnitude higher than that of pure aerogels, and one order of magnitude higher than that of all kinds of composite aerogels. This work solves two major limiting factors in the utilization of aerogel materials, and presents a new design principle for high strength aerogels. It also offers a potential basal material for future multifunctional aerogel design.