LASER IMPLANTATION OF ANTHRACENE MOLECULES INTO POLY(ALKYL METHACRYLATE) FILMS OF DIFFERENT GLASS-TRANSITION TEMPERATURES

A polymer film doped with anthracene molecules (source film) was overl aid with a neat polymer film (target film) and irradiated with a XeF e xcimer laser passing through the target film. At a laser fluence below the ablation threshold of the source film, anthracene molecules were ejected from the source film and implanted into the contacting target film. A fluorescence image of the implanted molecules was clearly obse rved at the surface of the target film under a microscope. The observa tion by a scanning electron microscope confirmed the absence of transf erred polymer fragments at the surface of the target film. The number of transferred molecules from the source to the target films upon exci mer laser irradiation was estimated from the changes in fluorescence i ntensity of the target films and analyzed in terms of an Arrhenius plo t. The mass transfer is revealed to be a photothermally activated diff usion process and the activation energy associated with the diffusion of anthracene molecules in PMMA and PEMA matrices is estimated.