Adjustable dielectric and bioactivity characteristics of chitosan-based composites via crosslinking approach and incorporation of graphene

Abstract

This study explores the structural, electrical, dielectric, and bioactivity properties of chitosan (CS) composites incorporating graphene (G) nanoparticles. Characterization techniques, including Field Emission Scanning Electron Microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), dielectric spectroscopy, and in vitro testing in SBF, were employed to investigate the effects of G content and crosslinking. The XPS peak at 289.89 eV for CS-G10 indicates CC and CH bonds, suggesting significant interactions between chitosan's hydroxyl groups and graphene's carbon atoms, ensuring structural homogeneity. Dielectric constant (ε') gradually increased with G loading (0 %, 1 %, 5 %, and 10 %) for uncrosslinked composites, reaching 17.94, 18.92, 28.28, and 41.1, respectively. Crosslinked composites exhibited reduced ε' values (15.71, 15.42, 14.14, and 27.03) compared to non-crosslinked ones, with marginal increases post-percolation threshold (5 wt% G filling). XRD analysis revealed shifts in characteristic peaks of CS after SBF treatment, with new peaks at 28.9° and 48.5° indicating hydroxyapatite presence, confirming composite bioactivity. CS-G10/GA showed the highest bioactivity, suggesting promise for biomedical applications.

Keywords: Bioactivity; Chitosan; Dielectric permittivity; Graphene; Polymer nanocomposites; SBF.