Synergistic strengthening mechanisms in graphene oxide/carbon nanotube hybrid nanocomposites: a multiscale experimental and computational study

Abstract

ABSTRACT This study presents a comprehensive multiscale experimental and computational investigation into the synergistic strengthening mechanisms operative in graphene oxide (GO)/carbon nanotube (CNT) hybrid nanocomposites embedded in an epoxy matrix. echanical characterization encompassing tensile testing, dynamic mechanical analysis (DMA), fracture toughness measurements, and impact strength evaluation revealed that the 1:1 GO:CNT hybrid at 2 wt% loading achieved a 75% improvement in tensile strength (102.1 MPa vs. 58.3 MPa for neat epoxy), a 93% increase in fracture toughness (1.31 MPa·m0·5 vs. 0.68 MPa·m0·5), and a 139% enhancement in impact strength compared to the unfilled matrix. These synergistic improvements significantly exceeded the arithmetic sum of improvements attributable to the individual fillers alone, confirming genuine synergism. Molecular dynamics (MD) simulations and finite element analysis (FEA) were employed to elucidate the mechanistic origins of the synergy, revealing that GO–CNT junction networks augment stress transfer efficiency to 91.3%, that covalent crosslinking at GO–CNT interfaces elevates interfacial binding energy from −3.21 eV (GO/epoxy) to −7.12 eV. Thermal characterization demonstrated a 19 °C elevation in glass transition temperature and a 340% increase in thermal conductivity for the optimal hybrid.