3D Lamellar?Structured Graphene Aerogels for Thermal Interface Composites with High Through?Plane Thermal Conductivity and Fracture Toughness

• 作者: Chao Shu Peng Min Pengfei Liu Xiaofeng Li Xiyuan Chang Yun Ding Zhong-Zhen Yu
• 来源期刊: 纳微快报（英文）
• 年，卷（期）: 2021,（2）
• 页码范围: 13-27
• 页数: 15页
• 语种: 英文

摘要

Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers, the resulting nanocomposites usually exhibit low through-plane thermal conductivities, limiting their application as thermal interface materials. Herein, lamellar-structured polyamic acid salt/graphene oxide (PAAS/GO) hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by lyophilization. Subsequently, PAAS monomers are polymerized to pol-yimide (PI), while GO is converted to thermally reduced graphene oxide (RGO) during thermal annealing at 300 ℃. Final graphitization at 2800 ℃ converts PI to graphitized carbon with the inductive effect of RGO, and simultaneously, RGO is thermally reduced and healed to high-quality gra-phene. Consequently, lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time, and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene lamellae. After vacuum-assisted impregnation with epoxy, the resultant epoxy composite with 2.30 vol％ of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m?1 K?1, 100 times of that of epoxy, with a record-high specific thermal conductivity enhancement of 4310％. Furthermore, the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness, ～ 1.71 times of that of epoxy.