One-step fabrication of regular hierarchical micro/nano-structures on glassy carbon by nanosecond pulsed laser irradiation

Fabrication of hierarchical micro/nano-structures on glassy carbon (GC) surface is important for the application of GC as the mold material for glass molding, but it is still challenging due to the high brittleness and hardness of the material. In this study, by using a nanosecond pulsed laser, a hierarchical micro/nano-structure, i.e., micro-dimple with ring-like nanostructure on its inner wall, was generated on the GC surface. The effects of laser parameters, such as laser irradiation time and fluence, on the formation and evolution of the hierarchical micro/nano-structure were experimentally studied. By comparative experiments with graphite, the role of amorphous nature of GC on the formation of very regular hierarchical micro/nano-structure was confirmed. The results obtained by irradiating GC in argon and nitrogen gas further indicated that the formation of hierarchical micro/nano-structure was independent of the gas atmosphere. By controlling the relative positions of point shots, various micro-dimple arrays were successfully fabricated on the GC surface which significantly changed its wetting behavior. Finally, formation mechanism of the hierarchical micro/nano-structure was discussed according to the experimental results as well as some previous literatures. This study provides a one-step method for fabricating hierarchical micro/nano-structures on the GC surface by nanosecond pulsed laser irradiation, which would be meaningful for the functional applications of GC.