Interfacial properties of carboxylic acid functionalized CNT/polyethylene composites: A molecular dynamics simulation study

A periodic molecular dynamics (MD) model is proposed to investigate the mechanical properties of the interface between a functionalized single-walled carbon nanotube (SWNT) and matrix, with “end effect” eliminated. The load transfer mechanism in the layer of interphase surrounding SWNT is investigated as the SWNT is sliding in the polymer. It is indicated that the deformation of the interphase is mainly driven by the functional groups, which determines the interfacial properties that is found to be sensitive to the sliding velocity. The effective interfacial shear strengths in different sliding stages and variable sliding velocities are evaluated, and an empirical model is proposed to describe the effect of the sliding velocity and the amount of functionalization on the interfacial strength. Based on the calculation of shear properties of polyethylene (PE) bulk and an equivalent shear load transfer model, we did an original investigation of the interfacial properties determined by the amount of functionalization of SWNT and the sliding velocity. In addition, a criterion is proposed to characterize the strength of the interface. The results show that the assumption of perfect bonding is reasonable for the modeling of these functionalized SWNT/PE composites at a higher scale.