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 overlaid with a neat polymer film (target film) and irradiated with a XeF excimer 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 observed at the surface of the target film under a microscope. The observation by a scanning electron microscope confirmed the absence of transferred polymer fragments at the surface of the target film. The number of transferred molecules from the source to the target films upon excimer laser irradiation was estimated from the changes in fluorescence intensity of the target films and analyzed in terms of an Arrhenius plot. The mass transfer is revealed to be a photothermally activated diffusion process and the activation energy associated with the diffusion of anthracene molecules in PMMA and PEMA matrices is estimated.