Investigation of phonon transport and thermal boundary conductance at the interface of functionalized SWCNT and poly (ether-ketone)

Abstract

The thermal and electrical applications of many polymers commonly used in commercial and defense applications are scarce due to their low conductivities. The fillers of carbon nano-structures such as single-walled carbon nanotubes (SWCNTs) in the polymer matrix can lead to significant improvement in the thermal and electrical properties of the resulting nano-composite. An exceptional improvement in the electrical and thermal conductivity of fibers made by poly (ether) ketone (PEK) grafted few walled carbon nanotube has been observed in the experiments. However, the thermal interaction of SWCNT and PEK molecules has not been understood yet. In this study, the SWCNT is covalently bonded to PEK molecules using crosslinking methodology and the interfacial thermal boundary conductance between SWCNT and PEK are estimated using molecular dynamics methods, non-equilibrium/direct method. The phonon transport at the interface of SWCNT and PEK is investigated by computing the spectral energy density and the decay of spectral temperature in different frequency bands of SWCNT for different number of covalent bonds between SWCNT and PEK. The analysis elucidate that covalent bond between the SWCNT and PEK significantly enhances the thermal coupling at the interface compared to non-bonded SWCNT, but the thermal transport saturates after a certain number of covalent bonds between SWCNT and PEK.