Experimental study of thermal conductivity of polyethylene nanowire arrays fabricated by the nanoporous template wetting technique

We fabricate low-density polyethylene (LDPE) nanowire array with a diameter of 200 nm by using a nanoporous template wetting technique, and the thermal conductivity at 20-80°C is experimentally studied by a nanosecond laser flash method. The measured thermal conductivity of the fabricated nanowire array is about 2.2 W/mK at room temperature, which is about one order of magnitude higher than its bulk counterpart. The thermal conductivity is found to increase slightly with the increase of temperature. The estimated thermal conductivity of a single LDPE nanowire is as high as 5 W/mK at room temperature. The high orientation of chain of the LDPE nanowire may arise from the integrative effects of shear rate, vibrational perturbation, translocation, nanoconfinement and crystallization. Findings in this study provide a useful strategy for enhancing the intrinsic thermal properties of polymer nanostructures.