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

Abstract

a b s t r a c tThere 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 (Hbonds). 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.

Mechanics of spontaneously formed nanoblisters trapped by transferred 2D crystals

“…The emergence of each new material brings demands for exploring its vdW interactions with various types of substrates and 2D materials, as many exciting applications of these materials come from stacking them into multilayers and heterostructures. Because of the significance of vdW interactions, many experimental studies have been carried out to measure the adhesion energy of 2D material interfaces, e.g., pressurized blister (8), buckling-based metrology (41)(42)(43), and double-cantilever method (44,45), as summarized in recent review papers (3,46). However, it is tedious or impossible to determine the adhesion energy for every pair of 2D material interfaces.…”

Measuring Interlayer Shear Stress in Bilayer Graphene

“…Details in the insets clearly show the Raman shift as a function of the spatial position in the monolayer and bilayer graphene samples. Interestingly, the measured Raman shift exhibited nearly linear characteristics near the edge of the shear zone, typically implying a constant strain gradient due to a constant interfacial shear stress in one-dimensional scenarios [47,48]. Such linearity also enabled us to clearly determine the radius ratio ρ for the annular shear zones (marked by red lines and symbols), with respect to Δp.…”

In situ mechanical characterization of silver nanowire/graphene hybrids films for flexible electronics

“…The interlayer shear effect of the multilayer graphene film may lead to the weakening of the stiffness [46,47]. Moreover, the van der Waals interface connection between the AgNWs and graphene film and the cross-link density of the nanowires also can contribute to the stiffness of the hybrid film [25][26][27]48,49]. Compared with a pure graphene film, the hybrid film showed a comparable fracture strain [20,21].…”