THE EFFECTS OF EXTERNAL CONDITIONS ON THE INTERNAL STRUCTURE OF CARBON AEROGELS

Carbon aerogels with various particle (grain) sizes, mass densities and heat-treatment temperature were studied. Effects of these externally controllable parameters on the internal structure and properties of the carbon aerogel material were examined using techniques such as room-temperature Raman spectroscopy, temperature-dependent magnetic susceptibility and temperature-dependent dark- and photo-conductivities. The results show that the in-plane microcrystallite size increases with heat-treatment temperature, the electrical conductivity increases with mass density, and the particle size affects the unpaired spin disorder present, The transport mechanism common to all the samples is attributed to a variable-range hopping about a Coulomb gap.