Influence of oxygen ion irradiation on the chemical, structural, and morphological properties of poly(2,5-benzimidazole)/graphene oxide composites

This study investigated the chemical, structural, and morphological evolution of poly(2,5-benzimidazole)/graphene oxide (ABPBI/GO) composites exposed to 4 MeV O 2 + ion irradiation at fluences from 1 × 1 0 12 to 1 × 1 0 15 ions/cm 2 . Fourier Transform Infrared (FTIR) spectroscopy indicated dose-dependent degradation, with aromatic C=C/C=N groups exhibiting the most pronounced broadening (87.82%). X-ray Diffraction (XRD) analysis indicated the predominantly amorphous nature of ABPBI/GO, with increased peak intensities upon irradiation. Scanning Electron Microscopy (SEM) indicated a fluence-dependent morphological transition: surface defects increased from 286 (control) to 813 features at 1 × 1 0 14 ions/cm 2 , then coalesced into ridge-like structures at the highest fluence, where the defect count dropped to 172 features. Pore analysis indicated median pore diameters remained near ∼ 0.5 μ m , with larger pores ( > 2 μ m ) emerging at higher fluences. Atomic Force Microscopy (AFM) showed non-monotonic surface roughness, with root mean square (RMS) roughness increasing from 15.38 nm (control) to a maximum of 19.68 nm at 1 × 1 0 13 ions/cm 2 , then decreasing to ∼ 13.5 nm at higher fluences. The Stopping and Range of Ions in Matter (SRIM) calculations showed that electronic stopping dominates energy deposition ( S e / S n ≈ 341 ), with peak displacements per atom (DPA) ranging from 1.61 × 1 0 − 4 to 1.61 × 1 0 − 1 , providing a quantitative link between energy deposition and the observed radiation-induced degradation.