Thermal conductivity of electrospinning chain-aligned polyethylene oxide (PEO)

Polymer fibers' thermal conductivity along its axis direction are usually much better compared to that of the bulk. Many researches indicate that three main factors have significant impact on polymer fiber's thermal conductivity, which are crystallinity, molecular alignment and crystalline grain orientation of the polymer. Most research focus on polyethylene (PE) because of its relatively high crystallinity. Here, we report exceptionally high thermal conductivity on electrospun polyethylene oxide (PEO) nanofibers, which is an important semicrystalline polymer. This indicates that semicrystalline polymers like PEO can also obtain high thermal conductivity, which may be used in areas such as electronic devices. Its thermal conductivity improved about 150 times over bulk polymer. By using infrared spectroscopy, we evidenced that improvement in thermal conductivity was ascribed to increased molecular alignment. And we discussed the relationship between molecular alignment and crystalline grain orientation, as well as their contribution to the thermal conductivity of PEO fibers. We found that for PEO nanofibers, preferred molecular alignment in the amorphous region has significant contributed to high thermal conductivity. (C) 2017 Elsevier Ltd. All rights reserved.