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The physical properties of multilayers with layer periods in the nanometer range crucially depend on the nature of their interfaces. In this contribution we show how the interfacial roughness of multilayers consisting of two materials with a high difference in specific surface free energy (here MgO/Fe) and thus different growth modes (Volmer–Weber island growth for Fe and layer-by-layer growth for MgO) can be minimized. For this, the layer thickness of the island former has to be large enough that almost all island zipping processes have already occurred. At this thickness the layer is just closed and the intrinsic roughness is at a minimal value. To determine this optimal thickness, in-situ stress measurements as performed in this work are one method of choice. The layer-by-layer growth of the other material with lower surface free energy additionally leads to a further smoothening of the surface. Due to this alternating roughening and smoothing processes, cumulative roughness can be avoided and overall a minimal roughness of the multilayer structure is obtained. peerReviewed

Pulsed laser deposition (PLD) at 248 nm in ultra high vacuum was used to produce thin poly(methyl methacrylate) (PMMA) and poly(ethyl methacrylate) (PEMA) films. The ablation and deposition mechanisms were found to be similar in both systems. Having the same backbone, these polymers differ in the size of their polar side groups leading to changes in their dynamics. Studies of the relaxation processes were performed using mechanical torsion and bending spectroscopy by means of a double-paddle oscillator (DPO) and an in-situ plasma plume excited reed (PPXR), respectively. A strong increase of the mechanical damping was observed during annealing of the polymer films well above the glass transition temperature T g, while in-situ X-ray measurements did not reveal any structural changes. For PEMA, the glass transition temperature T g=335 K and the main absorption maximum appear at lower temperatures compared to PMMA (T g=380 K), allowing one to measure the mechanical properties in a much wider range above T g. peerReviewed

Complex polymer–metal nanocomposites have a wide range of applications, e.g. as flexible displays and packaging materials. Pulsed laser deposition was applied to form nanostructured materials consisting of metal clusters (Ag, Au, Pd and Cu) embedded in a polymer (polycarbonate, PC) matrix. The size and amount of the metal clusters are controlled by the number of laser pulses hitting the respective targets. For Cu and Pd, smaller clusters and higher cluster densities are obtained as in the cases of Ag and Au due to a stronger reactivity with the polymers and thus a lower diffusivity. Implantation effects, differences in metal diffusivity and reactivity on the polymer surfaces, and the coalescence properties are discussed with respect to the observed microstructures on PC and compared to the metal growth on poly (methyl methacrylate), PMMA. peerReviewed