Theory predicts that dewetting of a homogeneous liquid film from a solid surface may proceed via unstable surface waves on the liquid. This phenomenon, usually termed spinodal dewetting, has been sought after in many systems. Observations in liquid crystal and liquid metal films showed that, as expected, the emerging structures were similar to those found for spinodal decomposition in mixtures. Certain differences, however, could be attributed to peculiarities of the wetting forces in these two dissimilar systems, thereby demonstrating the role of nonlinearities inherent in the wetting forces.

Light reflection from computer monitors, car dashboards and any other optical surface can impair the legibility of displays, degrade transmission of optical components and in some cases may even pose safety hazards. Antireflective coatings are therefore widely used, but existing antireflection technologies often perform sub-optimally or are expensive to implement. Here we present an alternative approach to antireflection coatings, based on an extension of our photo-aligning and photo-patterning technology for liquid-crystal displays (LCDs) and liquid-crystal polymer films with smooth surfaces to optical polymer films with controlled surface topologies. Nano- and micro-corrugated topologies are shown to result from optically induced monomer phase-separation on the polymer surfaces. The properties of the resulting films make them suitable high-performance and low-cost antireflection coatings for optical components of virtually any size, shape and material. Moreover, the approach can be used to form a wide range of other functional polymer thin films with isotropic as well as anisotropic topologies. For example, films can be produced whose optical birefringence exceeds that of the birefringence of the polymer material itself. These new films can also be used as diffractive thin films, diffusers, and directional reflectors which preserve light polarization, or as substrates for aligning liquid crystals to produce bright, low-power-consumption LCDs with integrated optical functions and memory.

A wide series of diruthenium(II,II) tetracarboxylates of general formula Ru2(RCOO)4 was prepared; the carboxylate substituents include linear alkyl chains (R = C4H9 to C19H39), unsaturated chains (R = CH2=CH(CH2)8~, (CH3)2C=CHCH2CH2CH(CH3)CH2-) as well as a fluorinated chain (R = C7F15-). An adduct obtained by pyrazine intercalation was also characterized (R = CnH23-). The mesomorphic behavior of these compounds was investigated by differential scanning calorimetry and X-ray diffraction. A thermotropic columnar mesophase was observed above ca. 100 °C for all complexes except the perfluoro compound and the pyrazine adduct. Unsaturation in the peripheral alkyl chains strongly depresses the transition temperature to the liquid-crystalline phase. The magnetic susceptibility of three members of the series was measured in the range 6-400 K. A rigorous analytical expression of the magnetic susceptibility vs temperature was derived from the ( *)* 12( *)2 electronic configuration for the ground state of a diruthenium(II,II) core, by applying a spin-orbit Hamiltonian, and the data were successfully analyzed on this basis.

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