Interfacial energy dissipation in bio-inspired graphene nanocomposites

Bio-inspired nanocomposites have been fabricated by self-assembly using graphene oxide (GO) based fillers, and their interfacial energy dissipation during cyclic deformation has been studied. The GO flakes were washed with a base solution to remove some functional groups and this base-washed GO (BwGO) obtained was also employed as a comparison to study the effect of functional groups on the interface. Raman spectroscopy was used to monitor the deformation of the fillers and to determine their stress-strain curve in the nanocomposites. The area of the hysteresis loop between the loading and unloading curves was used to calculate the interfacial energy dissipation during cyclic deformation. The presence of functional groups on GO reduced the interfacial energy dissipation in the elastic regime. The energy dissipation starts to increase with strain, and eventually when the applied strain is beyond the elastic regime, the functional groups ‘toughen’ the interface by requiring higher energy to break and also roughening the interface, similar to the behaviour of the biological composites. This work has shed light on the fabrication of bio-inspired nanocomposites and the evaluation and application of the graphene-based fillers where energy dissipation is needed, for example, in composites toughening and the damping of elastomers.