title: Flyweight 3D Graphene Scaffolds with Microinterface Barrier-Derived Tunable Thermal Insulation and Flame Retardancy.
abstract: In this article, flyweight three-dimensional (3D) graphene scaffolds (GSs) have been demonstrated with a microinterface barrier-derived thermal insulation and flame retardancy characteristics. Such 3D GSs were fabricated by a modified hydrothermal method and a unidirectional freeze-casting process with hierarchical porous microstructures. Because of high porosity (99.9%), significant phonon scattering, and strong π-π interaction at the interface barriers of multilayer graphene cellular walls, the GSs demonstrate a sequence of multifunctional properties simultaneously, such as lightweight density, thermal insulating characteristics, and outstanding mechanical robustness. At 100 °C, oxidized GSs exhibit a thermal conductivity of 0.0126 ± 0.0010 W/(m K) in vacuum. The thermal conductivity of oxidized GSs remains relatively unaffected despite large-scale deformation-induced densification of the microstructures, as compared to the behavior of reduced GSs (rGSs) whose thermal conductivity increases dramatically under compression. The contrasting behavior of oxidized GSs and rGSs appears to derive from large differences in the intersheet contact resistance and varying intrinsic thermal conductivity between reduced and oxidized graphene sheets. The oxidized GSs also exhibit excellent flame retardant behavior and mechanical robustness, with only 2% strength decay after flame treatment. In a broader context, this work demonstrates a useful strategy to design porous nanomaterials with a tunable heat conduction behavior through interface engineering at the nanoscale.
authors.affiliation: School of Civil Engineering and Mechanics, Lanzhou University , Lanzhou 730000, P. R. China.|Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, The Ministry of Education of China , Lanzhou 730000, P. R. China.|School of Civil Engineering, Harbin Institute of Technology , Harbin 150090, P. R. China.
authors.forename: Qiangqiang
authors.identifier: http://orcid.org/0000-0002-6082-6782
authors.initials: Q
authors.lastname: Zhang
authors.forename: Menglong
authors.initials: M
authors.lastname: Hao
authors.affiliation: School of Civil Engineering, Harbin Institute of Technology , Harbin 150090, P. R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Xu
authors.forename: Guoping
authors.initials: G
authors.lastname: Xiong
authors.affiliation: School of Civil Engineering, Harbin Institute of Technology , Harbin 150090, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Fisher
keywords: 3D graphene scaffolds; flame retardant; interface engineering; microinterface barrier; thermal insulating; tunable heat conduction