ReaxFF Simulations of Laser-Induced Graphene Formation

Polymer films subjected to CO2 infrared laser irradiation in ambient conditions undergo a transformation, resulting in the formation of porous graphene known as laser-induced graphene (LIG). In this presentation, we will discuss finding from reactive molecular dynamics simulations (ReaxFF) to investigate LIG formation from five different polymers structures. Our research revealed that the initial molecular structure of the parent polymer significantly influences the resulting graphitic structure. During the early stages of LIG formation, the polymer transforms into an amorphous structure, releasing CO, and subsequently evolves into an ordered graphitic structure, liberating H2 steadily. The resulting LIG exhibits out-of-plane undulations and bends due to the presence of numerous 5- and 7-member carbon rings throughout the structure. Our simulated molecular structure aligns well with recent experimental observations in the literature. Moreover, we observed that LIG yield is higher in inert conditions compared to oxygen-rich environments. Specifically, LIG derived from polybenzimidazole demonstrated the highest surface area and yield among the five polymers studied. These findings enhance our understanding of LIG formation mechanisms, offering valuable insights for various bulk LIG applications such as sensors, electrocatalysts, microfluidics, and precise polymer welding through targeted heating.