Pulsed laser deposition of polymer-metal nanocomposites

Different polymer-metal nanocomposites, metal clusters on a polymer surface and for the first time also polymer/metal multilayers, were pulsed laser deposited at a wavelength of 248 nm. Poly(methyl methacrylate) (PMMA) and Bisphenol A dimeth-acrylate (BisDMA), which strongly differ in their hardness of 3 and 180 N/mm2, respectively, were taken as polymer components. Metals Ag and Cu were chosen because of their different reactivity to polymers. When depositing Ag on PMMA, spherical clusters are formed due to high diffusion and total coalescence. For Cu, much smaller grains with partially elongated shapes occur because of lower diffusivity and incomplete coalescence. Compared to the results on the soft PMMA, the clusters formed on the harder BisDMA are much larger due to higher diffusivity on this underlayer. In PMMA/Cu multilayers, wavy layered structures and buckling is observed due to relaxation of compressive stress in the Cu layers. Smooth Cu layers with higher thicknesses can only be obtained, when the hardness of the polymer is sufficiently high, as in the case of BisDMA/Cu multilayers.