Tuning the Hydrophobicity of Laser-Annealed rGO Thin Films Synthesized by Pulsed Laser Deposition

Reduced graphene oxide (rGO) has captivated the scientific community due to its exceptional electrical conductivity, high specific surface area, and excellent mechanical strength. The physical properties of reduced graphene oxide (rGO) are strongly dependent on the presence of different functional groups in its structural framework, along with surface roughness. In this study, laser annealing was employed by a nanosecond Nd:YAG laser to investigate the impact of varying laser energies on the wettability and conductivity of reduced graphene oxide (rGO) samples grown by the pulsed laser deposition (PLD) technique. The rGO films were annealed with different laser fluences, such as 10, 20, 30, 38, 48, 55, and 250 mJ/cm². Our results reveal a notable transition in wettability, transforming the initially hydrophobic rGO samples into a hydrophilic state. Hydrophilic graphene oxide (GO) or reduced graphene oxide (rGO) surfaces have significant potential for use in biomedical applications due to their unique combination of properties, including biocompatibility, high surface area, and abundant oxygen-containing functional groups. Along with wettability properties, conductivity changes were also observed. The presented findings not only contribute to the understanding of laser-induced modifications in rGO but also highlight the potential applications of controlled laser annealing in tailoring the surface properties of graphene-based materials for diverse technological advancements.