The as-prepared CNF
aerogel has a very low apparent density of ca. 10 mg cm23, which
is comparable to those of spongy graphene (12 65 mg cm23)36 and
un-densified vertically aligned CNT arrays (10 mg cm23)41, and is
much less than those of the traditional carbon aerogels (100–800 mg
cm23)42,43 and hydrophobic nanocellulose aerogels (20–30 mg
cm23)7.