Study of Single-Walled Carbon Nanotube Aerogel Thermal Conductivity in the Gas Environment with Varying Aerogel Density

We will report on the thermal conductivity of a gas permeated single-walled carbon nanotube (SWCNT) aerogel as a function of density.  The SWCNT aerogel is a nano-porous material that is solution-formed and contains only pure SWCNTs.  The SWCNTs of the aerogel interact via van der Waals forces.  Densities in the range of 8-15 kg/m³ were considered.  By using kinetic theory to analyze the gas contribution to thermal conductivity in the SWCNT aerogel , a mean energy transport length scale was extracted.  This mean energy length scale was compared to the structurally limited mean free path of the gas molecules derived from mesoscale simulations.  The difference between these lengthscales was used to determine the thermal energy accommodation of various gases with the SWCNTs.  Measurements at a single aerogel density indicate low energy accommodation.  The SWCNT’s effective thermal conductivity versus the volumetric density of tube-tube junctions will be correlated from the density dependent measurements