Aerogel- A Recent Innovation In Gel

Aerogel is world’s lightest material and drug delivery system. Aerogel having more than 15 entries in Guinness Book of the world’s record is very low density solid state gel which is derived by replacing the dispersion phase of gel with gas. Aerogels are prepared by sol-gel process to extract liquid component of gel through super-critical drying. This allows the liquid removed without causing the solid matrix in gel to collapse due to capillary action. Aerogel possesses some properties like lowest density, lowest optical index of reflection, lowest electric constant and highest specific surface area. Materials used for preparation of aerogel include silica, metal oxides, organic and biological polymers, carbon nanotubes etc. Both hydrophilic and hydrophobic gels can be prepared. Solvents used for preparation of gel are explosive so, they are replaced by non inflammable liquid carbon dioxide. Applications of aerogel are very wide. Aerogels are used as a composite, as an absorbent, as a sensor, as a catalyst, as a thermal insulator, for improving dissolution properties of some drugs etc.