Percolation theory analysis of nacre‐like bioinspired poly(trimethylene terephthalate)/graphene nanosheets‐iron oxide composites

Abstract Biomimetic polymer composites with micro/nano‐scale brick‐and‐mortar structures show promise for advancing nacre‐like polymer bioinspired nanocomposites. This study used a solvothermal method to graft MIL‐101 onto graphene oxide (GO), forming GO‐g‐MIL‐101. Subsequent heat treatments at 700 and 900°C under inert gas produced magnetic graphene nanosheets (GNS@Fe) with iron oxide particles. Poly(trimethylene terephthalate) (PTT) served as the matrix. PTT/GNS@Fe powders were prepared by coagulation then formed into bioinspired PTT/GNS@Fe and PTT/GNS@Fe‐m composites via solvent casting and hot pressing, yielding brick‐and‐mortar structures with and without magnetic alignment. PTT served as the soft phase and GNS@Fe as the hard phase. Rheological and conductivity analysis of PTT bioinspired composites, based on percolation theory, revealed microstructural changes. Results show that magnetic field assistance enhances GNS@Fe alignment in PTT/GNS@Fe‐m composites. With higher GNS@Fe content, reduced interlayer spacing creates a PTT‐GNS@Fe network, where nanoscale confinement limits PTT chain mobility, impacting crystallization. Low GNS@Fe levels promote crystallization, while high levels hinder it, with PTT unable to crystallize in nacre‐like composites above 40 wt% GNS@Fe. Additionally, we tested the electromagnetic interference (EMI) shielding of the PTT/GNS@Fe bioinspired composite system, finding that the shielding efficiency of PTT/GNS@Fe‐m with 40 wt% filler, though affected in magnetism by processing, approaches commercial application levels. Highlights Rheological and conductivity analysis via percolation theory. Percolation analysis revealed microstructures in the nacre‐like composite. Magnetic self‐assembly in PTT/GNS@Fe‐m led to more oriented structures. Higher GNS@Fe content reduced spacing, forming PTT‐GNS@Fe networks. Nanoconfinement and adsorption limited PTT chains, reducing crystallinity.