Development of enhanced co-continuous PVDF/PET nanocomposites via synergistic effects of graphite particle size, hybrid systems, and reduced graphene oxide

Abstract This study explores the development of electrically conductive co-continuous polyvinylidene fluoride/polyethylene terephthalate (PVDF/PET) nanocomposites incorporating graphite (GR) and reduced graphene oxide (rGO) for potential use in proton exchange membrane fuel cell (PEMFC) bipolar plates. The influence of GR particle size, concentration (20–60 wt%), and hybrid GR/GR and GR/GR/rGO combinations on electrical, thermal, mechanical, and water absorption properties was systematically investigated. Scanning electron microscopy revealed GR localization within the PET phase and the formation of a dense conductive network. The optimal composition, a hybrid G2/G3 (45/15 wt%) system, achieved low through-plane (0.93 Ω cm) and in-plane (0.71 Ω cm) resistivities, further reduced with 2 wt% rGO (0.89 Ω cm through-plane and 0.62 Ω cm in-plane). This formulation also exhibited superior thermal stability (onset degradation at ∼490 °C) and mechanical properties, with a flexural strength of 44.4 MPa and modulus of 16.4 GPa. Additionally, water absorption decreased significantly to 0.05 %. These findings demonstrate the potential of hybrid GR/rGO nanocomposites for enhanced durability and performance in PEMFC applications, offering a balance between electrical conductivity, mechanical strength, and environmental resilience.