The effect of mesoscopic shape on thermal properties of multi-walled carbon nanotube mats

We highlight the effect that mesoscopic shape of individual multi-walled carbon nanotubes (MWCNTs) has on their collective thermal properties when they are lumped together into MWCNT mats. The thermal properties depend both on the mesoscopic shape of the MWCNTs and on the structure of the mat. The mesoscopic shape is represented by static bending persistence length (l_sp) and the mat structure is represented by network length (l_e). It is demonstrated that various thermal properties depend on l_sp. The variable thermal properties are linear thermal expansivity, thermal diffusivity, specific heat capacity, and thermal conductivity. In the case of n > 1, the MWCNT mats contract with increasing temperature. On the contrary, in the case of n < 1, the mats expand with increasing temperature. The apparent thermal conductivity increases with increasing l_sp.