This method produces silica aerogels which have low density, low thermal conductivity, ductility and mechanical integrity. These aerogels have many uses, but primarily serve as thermal insulators.
A better understanding of controlling the chemical process is needed to further reinforce the mechanical properties of silica aerogels, while retaining their other properties, especially their low thermal conductivities.
The method proposed involves 3 steps which provides better control of the cluster growth and formation of the gel network in an aerogel.
- Hydrolyzing an organosilicate precursor to form silanol groups under acidic conditions.
- Condensing the silanol groups under basic conditions with the help of a catalyst to form a polymeric silicate having a diverse range of pore sizes.
- Gelling the polymeric silicate.
- Two-to-four times improved ductility of silica aerogels using the 3-step method
- Better control of the sol-gel process allows user to achieve desired physical properties (lower thermal conductivity, lower acoustic velocity, lower dielectric constant).