materials prepared by replacing the liquid solvent in pores of a gel with air and without substantially altering the network structure of the volume of the gel body supercritical and sub critical fluid extraction technologies are commonly used to extract the solvent from the gel without causing the pores in the gel to collapse this material was first made by kistler in 1931 s s kistler nature 1931 127 764 the name aerogel describes a class of structures rather than a specific material a variety of different aerogel compositions are known and could be inorganic organic or inorganic organic hybrids inorganic aerogels are generally based on metal alkoxides and include materials such as silica s s kistler nature 1931 127 764 various carbides c i merzbacher et al j non cryst solid 2000 285 210 215 and alumina s j teichner et al adv colloid interface sci 1976 5 245 organic aerogels include but are not limited to urethane aerogels g biesmans et al 1998 225 36 resorcinol formaldehyde aerogels r w pekala u s pat no 4 873 218 and polyimide aerogels w rhine et al u s 2004132845 organic inorganic hybrid aerogels are primarily ormosil organically modified silica aerogels d a loy et al j non cryst solid 1995 186 44 the aerogels used in the current invention may belong to this category in which the organic components are chemically bonded to the silica network low density aerogel materials 0 01 0 3 g cc are widely considered to be the best solid thermal insulators better than the best rigid foams and have thermal conductivity values of 12 mw m k and below at 37 8 u00b0 c and atmospheric pressure aerogels function as thermal insulators by minimizing conduction low density tortuous.