Thermal Conductivity of Individual Electrospun Polymer Nanofibers

In this work, the thermal conductivity of individual polyethylene (PE) nanofibers fabricated by electrospinning was experimental measured. Our results show that polyethylene nanofibers can have a thermal conductivity up to 2.6 Wm⁻¹K⁻¹, (more than 9 times higher than the bulk PE value) and that the thermal conductivity is strongly correlated with the electric field intensity used in electrospinning. This, combined with micro-Raman characterization of individual nanofibers, suggests that the enhanced thermal conductivity is due to the high degree of orientation of the polymer chains. The stronger elongational forces experienced by the jet at higher electrospinning voltage result in the formation of nanofibers with a higher degree of molecular orientation. Similar thermal conductivity enhancement is also observed with other polymer nanofibers including polyethylene oxide (PEO), Nylon-6, and polyvinylidene fluoride (PVDF). Collectively, our results indicate that electrospinning could be an effective approach to produce polymer nanofibers with enhanced thermal conductivity.