From Corn Starch to Magnetic Laser-Induced Graphene Nanocomposite

Laser-Induced Graphene (LIG) is a versatile, three-dimensional, conductive material with high porosity and surface area, typically produced through laser irradiation of synthetic polymers with high thermal stability. Recently, there has been increasing interest in shifting toward sustainable, bioderived, and biodegradable materials as precursors for LIG. Among these, lignocellulosic materials have garnered attention, but starch—an abundant, renewable, and cost-effective biopolymer—remains unexplored in this context. This study demonstrates the successful conversion of corn starch bioplastic (SP) into LIG via iron-catalyzed laser-induced pyrolysis. Using Fe(NO₃)₃ as an additive, we investigate the formation of LIG and the impact of varying iron concentrations on the resulting material’s properties.
Our research reveals that the presence of iron is crucial for reliable and reproducible LIG synthesis, with only certain concentrations leading to optimal results in terms of graphenic/graphitic structure, as confirmed by Raman spectroscopy. The analysis of LIG’s crystal structure reveals both magnetic and non-magnetic phases of iron compounds, including γ-Fe₂O₃, Fe₃C, and Fe(C). TEM investigation revealed the formation of core/shell iron-based nanoparticles of different sizes, embedded within the LIG to form a nanocomposite. This LIG nanocomposite exhibits soft magnetic properties, with a coercive field of Hc ≈ 200 Oe and a saturation magnetization of Ms ≈ 67 emu g^-1.
The SP substrate degrades almost completely within 12 days when placed in soil, and this natural breakdown process remains unaffected by the inclusion of Fe(NO₃)₃ within the SP. This ensures the material’s compostability, supporting its potential use in sustainable applications aligned with circular economy principles.
This study highlights the potential of corn starch-derived LIG for sustainable applications, particularly in environmental remediation. Our findings open the door to further exploration of bioplastic-based LIG for use in degradable electronic devices, sensing platforms, and pollutant removal technologies. By utilizing a readily available and compostable biopolymer as a precursor, this research contributes to developing greener, more sustainable materials that align with global efforts toward reducing environmental impact. Our study thus sets the stage for future innovations in the field of degradable materials, with a focus on balancing functional performance with environmental responsibility.