Mechanical behavior and properties of hydrogen bonded graphene/polymer nano-interfaces

There is increasing evidence in literature for significant improvements in both toughness and strength of graphene-based nanocomposites through engineering their nano-interfaces with hydrogen bonds (H-bonds). However, the underlying mechanical behaviors and properties of these H-bonded interfaces at the microscopic level were still not experimentally clarified and evaluated. Herein, this work reports a study on the interfacial stress transfer between a monolayer graphene and a commonly used poly(methyl methacrylate) (PMMA) matrix under pristine vdW and modified H-bonding interactions. A nonlinear shear-lag model considering friction beyond linear bonding was proposed to understand evolution of interfacial stresses and further identify key interfacial parameters (such as interfacial stiffness, strength, frictional stress and adhesion energy) with the aid of in situ Raman spectroscopy and atomic force microscopy. The present study can provide fundamental insight into the reinforcing mechanism and unique mechanical behavior of chemically modified graphene nano-interfaces and develop further a basis for interfacial optimal design of graphene-based high-performance nanocomposites.