Mahendra S. Kavale

Effect of surface composition and roughness on the apparent surface free energy of silica aerogel materials

Surface chemical composition and morphology play an important role in determining the superhydrophobic behavior of solids. To provide insights on the influence of surface chemical composition and roughness on superhydrophobic behaviour of tetramethoxysilane based silica aerogel materials over a wide range, we have carried out a quantitative study of the effect of hydrophobic agent on contact angle and surface free energy of silica aerogels. The apparent surface free energy values were calculated using Zisman method and validated by Fowkes-Girifalco-Good theory.

Surfactant doped silica aerogels dried at supercritical pressure

By combining the molecular silica precursor methyltrimethoxysilane (MTMS) with methanol, water and Tween-80 solution, we get surfactant-doped silica alcogels. The wet alcogels can be exchanged with methanol and then supercritically extracted with nitrogen to produce surfactant-doped silica aerogels (SDSAs). SDSAs represent a new class of aerogels that are composed of aggregated submicron porous particles that have tunable interparticle nanoporosity. As we increased the percentage of surfactant, the physical properties of silica aerogels changes. In this study we characterized the SDSAs by SEM for morphological study, FTIR for the material composition, contact angle for hydrophobicity determination and thermal conductivity measurements are carried out for thermal insulation application.

Synthesis and physico-chemical properties of organic aerogels

Basically, an organic aerogel is any aerogel with a framework consists of organic polymers. The organic aerogels are fabricated by the sol-gel polymerization of resorcinol with formaldehyde, followed by exchanging with acetone, and then with liquid CO2 and drying under CO2 supercritical conditions. The organic aerogels obtained by this process exhibits themselves as an insulators i.e. they possesses high resistance to the flow of current through them. These obtained aerogels when heated at elevated temperatures of about 1100 °C they becomes conducting, demonstrates themselves a low resistance of the order of 4Ω.