new aerogels are disclosed which comprise silica and at least one organic polymer having polar functional groups . also disclosed are methods for making such aerogels and for making them as substantially transparent objects . in addition , gas detectors , liquid and gas absorbing objects , and optical devices made using these aerogels are disclosed . the present invention concerns optical elements which are substantially transparent and exhibit low refractive indices . the invention further relates to detectors of reactive and absorbate gases based on the physical changes exhibited by the aerogels upon reacting with or absorbing such gases . the present invention further concerns printable objects comprising these aerogels , specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes . the invention further concerns reactive gas absorbers comprising these aerogels and the catalytic function the aerogels serve to catalyze subsequent chemical reaction . furthermore , the present invention concerns the absorption of chemical compounds from condensed states including liquid , critical and supercritical fluids .