Extreme Phase Change Materials for Soldier Microclimate Regulation

Microclimate systems are being developed to minimize the effects of extreme temperature on performance capability and enable functioning under conditions that would otherwise cause incapacitation. It is important that these systems be highly reliable, lightweight and durable, with the intention to be worn under armor materials, heavy chemical/biological protective suits, and other protective clothing. This work involves guest-host interactions in nanomaterials. The nanomaterials that we will be investigating are those that involve nanospheres, nanotubes and nanobowls. These calixarenes complexes can house guest molecules in an ordered configuration. At certain temperatures these calixarenes can absorb enough thermal energy to cause the guest molecules to go into a disordered configuration, or the guest molecule absorbs enough energy to escape the calixarene host molecule. This energy needed to cause disorder of the guest molecules or the guest molecules escaping is between 500-1700J/g. This thermal energy needed is tremendous and could find uses in thermal energy storage applications such as phase change materials. In our phase 1 investigation we found one guest-host complex that had energies in excess of 3,000 jouies per gram. This is higher than the latent heat of vaporization of water.