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

Carbon aerogels with various particle (grain) sizes, mass densities an d heat-treatment temperature were studied. Effects of these externally controllable parameters on the internal structure and properties of t he carbon aerogel material were examined using techniques such as room -temperature Raman spectroscopy, temperature-dependent magnetic suscep tibility and temperature-dependent dark- and photo-conductivities. The results show that the in-plane microcrystallite size increases with h eat-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 attribu ted to a variable-range hopping about a Coulomb gap.