If so, wasn't it invented back in the 1930s?
Yes and yes - It isn’t any supermaterial, but it is a super pain to make, since you have to use supercritical (very high pressure - 75 atm) carbon dioxide to get the water out of the gel. You make the gel in a water solution, and then dry it, but if you just let it dry, the surface tension forces destroy the gel as it’s drying, Answer replace the water with liquid CO2 pressurize above the critical point - heat to convert the liquid CO2 to a gas without evaporation, and then let the CO2 leave.
Yes. It was used in a space probe to collect comet dust.