材料科学
热导率
环氧树脂
聚合物
热传导
热的
复合材料
螺旋(铁路)
纳米技术
热力学
机械工程
物理
工程类
作者
Xin Chen,Kai Wu,Yongzheng Zhang,Dingyao Liu,Runlai Li,Qiang Fu
标识
DOI:10.1002/adma.202206088
摘要
Polymers are usually considered thermal insulators; however, significant enhancements in thermal conductivity (k) have been observed in oriented fibers and films. Despite being advantageous in real-world applications, extending the linear thermal-transport advantage of polymers into the 3D space in bulk materials is still limited due to the spatially interfacial phonon-conduction barriers. Herein, inspired by the structure of tropocollagen, it is discovered that weaving hierarchically arranged poly(p-phenylene benzobisoxazole) (PBO) fibers with a spiral configuration into an epoxy matrix can yield a 3D continuous thermal pathway. This achieves both a through-plane k of 10.85 W m-1 K-1 and an in-plane k of 7.15 W m-1 K-1 . Theoretical molecular simulations in combination with classical nonlinear modeling attribute the above spatially thermally conductive achievement to not only the hierarchical molecular, spiral and weaving structure of PBO, but also the noncrystalline chains that carry overlapping phonon density of states, thus thermally bridging adjacent high-k crystals in the PBO fiber. Consequently, the interfacial thermal resistance among high-k PBO crystals is suppressed to be on the order of 10-10 m2 K W-1 in both the through-plane and in-plane directions. Other advantages include being lightweight, mechanically strong, flexible, and non-combustible. This material creates opportunities for organic polymers in high-performance thermal management applications.
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