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Multilayer Graphene Enables Higher Efficiency in Improving Thermal Conductivities of Graphene/Epoxy Composites
journal contribution
posted on 2016-05-03, 00:00 authored by Xi Shen, Zhenyu Wang, Ying Wu, Xu Liu, Yan-Bing He, Jang-Kyo KimThe
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.