Abstract
Several plastics subjected to femtosecond laser irradiation were first studied concerning surface roughness and wettability.Femtosecond laser irradiation could easily control the wettability and the surface free energy, and their variations depended on the polarity of the plastics. Next, the effects of shapes and chemical states on the wettability of plastic surfaces were investigated. Regardless of the plastic polarity, the contact angle of pure water changed continuously depending upon the surface roughness. On the other hand, there was no correlation between the contact angle and chemical state. It was revealed that from these results that the change of the wettability largely depended on the surface shape and could be controlled by laser irradiation.
