Single step in situ formation of porous zinc oxide/PMMA nanocomposites by pulsed laser irradiation: Kinetic aspects and mechanisms

The simultaneous in situ formation of zinc oxide nanoparticles and controlled porosity in poly(methyl methacrylate) films is presented herein as an innovative method for the preparation of polymer based porous nanocomposites. The process is based on the conversion of zinc acetate in spherical zinc oxide nanoparticles of 9 nm on average, by pulsed laser activated precursor decomposition. The kinetics of the nanoparticles formation, followed by UV-visible spectroscopy, show a remarkable increase of the reaction rate with respect to the conventional thermally activated process. Most importantly, as revealed by scanning electron microscopy investigations, the laser treatment leads to the simultaneous formation of a porous structure in the polymer matrix, which can be ascribed to the yielded gaseous by-products during the zinc oxide nanoparticle formation. The combination of all these characterizations allowed a deeper insight in the kinetic aspects and mechanisms involved in the single step formation of porous poly(methyl methacrylate)/zinc oxide nanocomposites with tailored characteristics that cannot be achieved by the conventional thermal treatment.