Model properties relevant to laser ablation of moderately absorbing polymers

• DOI: 10.1007/s00339-010-5754-5
• Publication Date: 2010-06-01T23:43:21Z
• Authors: S. Lazare; I. Elaboudi; M. Castillejo; A. Sionkowska
• Keywords: Laser Ablation; Polyvinyl acetate

A set of polymers including biopolymers and polymers from renewable resources are studied, with attention paid to their capability to form a foamy surface layer by laser irradiation. A model of laser-induced pressure wave is discussed, with its tensile tail giving rise to a fast and dense nucleation of cavities that can expand to microbubbles when filled with ablation gas. The intensity of the pressure wave has a maximum for an absorption coefficient of ∼1000 cm−1. Polyvinyl acetate, studied as a prototype polymer experimentally and by modeling, allows discussing the role of the viscosity drop in the dynamics of the laser-induced cavitations. In the Zeldovich frequency factor, a T (temperature) and P (pressure) dependent model of viscosity, and a T-dependent model of surface tension are introduced. It is further suggested that the well-known free-volume nanoholes existing in the material before the irradiation can constitute the nuclei of importance and that their concentration is one of the factors controlling the pre-exponential factor in the nucleation rate law.