Laser induced surface modification of polylactide

The modification induced in polylactide (PLA) by the ArF excimer laser radiation has been investigated. Various fluences and numbers of laser pulses were applied to modify surface properties. The contact angles of test liquids (water and diiodomethane) were measured with use of a goniometer while the surface energy (SE) was calculated by the Owens-Wendt method. Changes in the chemical composition of the PLA surface layer were studied using the X-ray photoelectron spectroscopy (XPS). Analysis of the morphological changes in the polymer surface layer was performed via the atomic force microscopy (AFM). It was found that the surface energy change was affected by surface oxidation as well as by surface roughness resulted from laser irradiation. The influence of laser induced surface oxidation and roughness on SE depended on applied fluence and the number of laser pulses.