纳米孔模板浸润法制备聚乙烯纳米线阵列的热导率的实验研究

摘要

采用纳米孔模板润湿技术制备了直径为200 nm的低密度聚乙烯（LDPE）纳米线阵列,并利用纳秒激光闪光法测量了20—80℃时LDPE纳米线阵列的热导率.测量得到室温时LDPE纳米线阵列的热导率为2.2W/mK,大约比其体材料的热导率高1个数量级,并且纳米线阵列的热导率随温度的升高略有增加.忽略纳米线之间的声子散射.估算得到室温下单根LDPE纳米线的热导率高于5 W/mK.本文制备LDPE纳米线热导率的提高源自其分子链定向度增加导致的低维导热效应的增强,纳米线的分子链定向度受工艺过程中流体剪切、振动、分子链迁移运动、纳米孔约束等几种因素的综合影响.%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℃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.