title: Multilayer Graphene Enables Higher Efficiency in Improving Thermal Conductivities of Graphene/Epoxy Composites.
abstract: The effects of number of graphene layers (n) and size of multilayer graphene sheets on thermal conductivities (TCs) of their epoxy composites are investigated. Molecular dynamics simulations show that the in-plane TCs of graphene sheets and the TCs across the graphene/epoxy interface simultaneously increase with increasing n. However, such higher TCs of multilayer graphene sheets will not translate into higher TCs of bulk composites unless they have large lateral sizes to maintain their aspect ratios comparable to the monolayer counterparts. The benefits of using large, multilayer graphene sheets are confirmed by experiments, showing that the composites made from graphite nanoplatelets (n > 10) with over 30 μm in diameter deliver a TC of ∼1.5 W m(-1) K(-1) at only 2.8 vol %, consistently higher than those containing monolayer or few-layer graphene at the same graphene loading. Our findings offer a guideline to use cost-effective multilayer graphene as conductive fillers for various thermal management applications.
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Xi
authors.initials: X
authors.lastname: Shen
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Engineering Laboratory for Functionalized Carbon Materials, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China.
authors.forename: Yan-Bing
authors.initials: YB
authors.lastname: He
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Jang-Kyo
authors.initials: JK
authors.lastname: Kim
keywords: Graphene; composites; number of layers; size; thermal conductivity