The bearable lightness of being carbon aerogel
A piece of carbon aerogel balanced on a flower at zhejiang university in hangzhou, china. Made of freeze-dried carbon nanotubes and graphene oxide with the oxygen then chemically removed, it is the lightest solid material in the world.
Because it is porous and highly hydrophobic, it can adsorb organic solvents and oils up to 312 times its own weight. It draws oil out of an oil/water mixture with high efficiency and selectivity, leaving behind pure water; this makes the new aerogel an ideal candidate for cleaning up oil spills or sucking up nonpolar industrial pollutants. The absorbed substances can easily be removed from the gel through distillation or combustion, allowing the gel to be used again.
The extraordinary heat and fire resistance of this material are particularaly noteworthy: repeated treatment with the flame of a torch caused no changes in its form or inner three-dimensional pore structure.
The high electrical conductivity of the aerogel also suggests the possibility of electronic applications. The material has high mechanical flexibility. it can be compressed to about 10% of its original volume and will subsequently expand back to nearly its original shape. Its conductivity decreases in a nearly linear fashion with increasing compression, which could allow the aerogel to be used as a pressure sensor.
image Ju Huanzong