Ultralow thermal conductivity of nanoparticle packed bed

We show that thermal conductivity of packed bed of alumina nanoparticles can be as low as 0.035 W/m K which is only 35% higher than the thermal conductivity of air and is smaller than the recently reported lowest thermal conductivity of solids using disordered layered WeS(2). These findings show a promising approach for making low-cost and ultralow thermal conductivity thermal insulation materials with high density and good sustainability at high pressures. (c) 2007 American Institute of Physics.