Different generation polyphenylene dendrimers possessing eight diphenylacetylene units in the dendritic scaffold between the layers of the first and second generation have been synthesized by using a new p-phenylene ethynylene-functionalized tetraphenylcyclopentadienone branching unit. The heterogeneous hydrogenation of the embedded triple bonds in the final dendrimers was successfully performed via heterogeneous catalysis. Moreover a "softening" effect of the dendritic structure in consequence of the hydrogenation is observed, allowing for the first time the investigation of this effect upon size, shape, and intramolecular voids in the case of similar dendrimer pairs. Quartz microbalance studies revealed that upon hydrogenation the capacity in host uptake is decreased allowing the incorporation of a lower number of guest molecules compared to the parent materials.

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Corrosion protection of mild steel by zinc phosphate coatings produced by electrolytic phosphating under cathodic polarization was investigated by electrochemical and surface analytical techniques. The cathodically produced coating mainly consists of zinc phosphate as hopeite, with incorporation of a small amount of metallic zinc. Surface characterization by X-ray diffraction, SEM and energy dispersive X-ray as a function of exposure time in neutral and alkaline solutions gives information on solution-induced changes of the protective layers. In neutral NaCl solution, the electrolytic zinc phosphate coating shows a very good corrosion protection, which even increases as a function of exposure time. Surface analytical investigations reveal that this is due to a formation of an underlayer of Zn(OH) 2 at the metal/coating interface. This corrosion product layer is an additional barrier blocking the bare metal surface in the pores of the zinc phosphate coating. In alkaline solution, phosphate is preferentially dissolved from the coating, changing the chemical composition of the coating to ZnO.

Several macrocycles of the Hunter-Vögtle type have been identified as superior host compounds for the detection of small amounts of acrylamide. When coated onto the surface of a quartz microbalance, these compounds serve as highly sensitive and selective sensor-active layers for their use in electronic noses. In this study, differently substituted macrocycles were investigated including an open-chain analogue and a catenane. Their structure and functional groups are correlated with their observed affinities to acrylamide and related acids and amides. The much smaller response of the open-chain compound and the almost absent sensor response of the catenane suggest that binding occurs within the cavity of the macrocycle. Theoretical calculations agree well with the experimental data even though they do not yet take into account the arrangement of the macrocycles in the sensor-active layer. The lower detection limit of acrylamide is 10 parts per billion (ppb), which is impressively low for this type of sensor. Other related compounds such as acrylic acid, propionamide, or propionic acid show no or significantly lower affinities to the macrocycles in these concentration ranges.