Polymer nanowire arrays with high thermal conductivity and superhydrophobicity fabricated by a nano-moulding technique

High thermal conductivity and superhydrophobicity are highly desired for micro/nanofluidic devices. Good thermal conductivity is helpful for thermal control and managements. Superhydrophobicity can benefit fluid friction reduction and liquid droplet control. We report on an improved nano-moulding technique which can prepare polymer (high density polyethylene/HDPE) nanowire arrays with high thermal conductivity (more than 10W/mK) and superhydrophobicity (contact angle >150°). The thermal conductivities of the fabricated high-density polyethylene (HDPE) nanowire arrays with diameters of 100 nm and 200 nm, measured by a laser flash method, are about 2 orders of magnitude higher than their bulk counterparts. The estimated thermal conductivity of a single HDPE nanowire is as high as 26.5 W/mK at room temperature. The self-organized surfaces of polymer nanowire arrays are found to have micro-to-nanoscale hierarchical nanostructures, and have superhydrophobicity of >150°. contact angles. This technique is promising for fabrication of micro/nanofluidics devices due to the advantages of simple fabrication, high-quality, low-cost, and mass-production.