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mosphere. The graphite cathode of 10 mm diameter was placed horizontally facing the composite anode of 6.15 mm diameter. The latter had a 3.2 mm diameter hole drilled 25 mm filled with a mixture of graphite (Graphit, fein gepulvert reinst, Merck, Germany) and Si powder in the atomic ratio 1:1.The experiments were repeated with and without the addition of 0.03 at.-% of Fe powder to the anode. During arc-discharge evaporation of the graphite/ silicon composite anode a hard cylindrical deposit (the core deposit) grows at the end of the graphitic cathode. Additionally a soot-like deposit is formed around the core deposit of the cathode, here called the collaret deposit. Samples for TEM examination were prepared from the core deposit as well as from the collaret deposit. The deposits were diluted in chloroform, sonicated for 5 min and dropped on a TEM Cu grid (300 mesh) with holey carbon film.The characterization of the samples was performed using TEM, HRTEM, electron diffraction, and analytical electron microscopy using EELS.TEM was carried out with a JEM 2000FX (JEOL, Japan), using an acceleration voltage of 200 kV, HRTEM was carried out with a JEM 4000EX (JEOL, Japan), using an acceleration voltage of 400 kV, and EELS was carried out with a PEELS 666 (Gatan, USA) on a dedicated STEM VG HB 501 UX (Vacuum Generators, UK) operating with a cold field emission gun at 100 kV acceleration voltage. All EELS data were acquired and processed using the EL/P 3.0 software (Gatan, USA). Pure Si and SiC powder samples prepared for electron microscopy in the same way as the arc discharge products were characterized by EELS in order to get reference spectra acquired under comparable conditions.The Si-L edges were acquired with an energy dispersion of 0.1 eV, a convergence angle of 10 mrad and a collector angle of 6.5 mrad. For the measurement of the Si-K edge the gun-lens was less excited to get a sufficient electron intensity at energy losses of about 1800 eV; the energy dispersion was adjusted at 1.0 eV. The Si-K edges were measured with a convergence angle of 10 mrad and a collector angle of 13 mrad.The energy location of the Si-L and the C-K edges was calibrated using zero-loss spectra acquired before the measurements. As a result the error of the energy location is less than ±0.2 eV. A deconvolution of the low-loss spectra was performed to remove the effect of sample thickness on the ELNES of the spectra.

Two columnar phases forming 2,4,6-triarylamino-1,3,5-triazines have been investigated in binary mixtures with calamitic and non-liquid crystalline benzoic acids carrying one or two alkoxy chains at the aromatic core. The triazines form hydrogen bonded aggregates with the complementary acids. Each investigated equimolar mixture exhibits a columnar mesophase due to segregation of the H-bonded polar core region from the lipophilic aliphatic molecular segments. The cross sectional shape of cylindrical aggregates and, therefore, the two-dimensional lattice symmetries, hexagonal or rectangular, are defined by the number of alkoxy chains of the benzoic acid component

New disc-shaped triarylamino-1,3,5-triazines were prepared by reaction of cyanuric chloride with two-fold alkoxy substituted anilines. Each of the tnarylmelamines exhibits an enantiotropic mesophase. X-ray investigations reveal the formation of columnar liquid crystalline structures with either a hexagonal or a rectangular lattice. The lattice parameters, as well as the intracolumnar ordering, depend on the length of the flexible lateral side chains. The new melamines form Langmuir monolayers at the air/water interface due to their amphiphilic nature. The monolayer organization is characterized by a side-on arrangement of the molecules. The polar central molecular parts lie flat on the water, whereas the lateral alkyl chains are oriented perpendicular to the water surface.

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