title: Stiffer but More Healable Exponential Layered Assemblies with Boron Nitride Nanoplatelets.
abstract: Self-healing ability and the elastic modulus of polymeric materials may seem conflicting because of their opposite dependence on chain mobility. Here, we show that boron nitride (BN) nanoplatelets can simultaneously enhance these seemingly contradictory properties in exponentially layer-by-layer-assembled nanocomposites as both surface coatings and free-standing films. On one hand, embedding hard BN nanoplatelets into a soft hydrogen bonding network can enhance the elastic modulus and ultimate strength through effective load transfer strengthened by the incorporation of interfacial covalent bonding; on the other hand, during a water-enabled self-healing process, these two-dimensional flakes induce an anisotropic diffusion, maintain the overall diffusion ability of polymers at low loadings, and can be "sealing" agents to retard the out-of-plane diffusion, thereby hampering polymer release into the solution. A detailed mechanism study supported by a theoretical model reveals the critical parameters for achieving a complete self-healing process. The insights gained from this work may be used for the design of high-performance smart materials based on other two-dimensional fillers.
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing and ‡Center for Composite Materials and Structures, Harbin Institute of Technology , 2 Yikuang Street, Harbin 150080, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Qi
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing and ‡Center for Composite Materials and Structures, Harbin Institute of Technology , 2 Yikuang Street, Harbin 150080, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing and ‡Center for Composite Materials and Structures, Harbin Institute of Technology , 2 Yikuang Street, Harbin 150080, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing and ‡Center for Composite Materials and Structures, Harbin Institute of Technology , 2 Yikuang Street, Harbin 150080, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing and ‡Center for Composite Materials and Structures, Harbin Institute of Technology , 2 Yikuang Street, Harbin 150080, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
keywords: BN nanoplatelets; layer-by-layer assembly; mechanical properties; nanocomposites; self-healing