THERMAL TRANSPORT IN CARBON NANOCOMPOSITES UNDER MECHANICAL STRAIN

In the present research study, we employ molecular dynamics simulations to investigate strain effect on the thermal conductivity of the polymer composites of carbon nanotubes (CNTs). The results show that the composite exhibits higher thermal conductivity than polymers. The thermal conductivity of polyethylene is only 0.45 W/m-K while the thermal conductivity of the composite reaches 0.57 W/m-K by being combined with a (10,0) single-walled CNT (SWCNT). It is observed that the thermal conductivity of the composite increases up to 1.01 W/mK with an increase in strain until C-C bonds in CNTs start to break. Strain rate is found to be related to the thermal conductivity of the composite; lower strain rate improves the thermal conductivity of the composite more efficiently by straightening the polymer chains better. By stretching polymer chains while leaving CNTs unstretched, however, we found that phonon scattering between polymer chains and CNTs is increased because of the increased surface contact between the polymer chains and the CNTs, impacting the thermal conductivity of the composite negatively. The results obtained in the present research study will be used to tailer the polymer composites of carbon nanostructures to have a better thermal performance under mechanical deformation, accelerating the development of futuristic flexible electronics and wearable devices.