@article{ReicheFreydankHelmsetal.1999,
  author    = {Reiche, J{\"u}rgen and Freydank, Anke-Christine and Helms, Andreas and Geue, Thomas and Schulz, Burkhard and Brehmer, Ludwig and Stiller, Burkhard and Knochenhauer, Gerald},
  title     = {Vacuum deposition films of oxadiazole compounds : formation and structure investigation},
  year      = {1999},
  abstract  = {The search for alternative routes of organic thin film formation is stimulated by the outstanding properties of these films in such fields as nonlinear optics, photonic data processing and molecular electronics. The formation of highly ordered multilayer structures by thermal vacuum deposition (VD) of organic compounds is an essential step toward the application of supramolecular organic architectures in technical systems. The VD of an amphiphilic substituted 2,5- diphenylene-1,3,4-oxadiazole 1 onto silicon substrates at defined temperature was used for the formation of ultrathin films. The structural data obtained for the VD-films of oxadiazole 1 by means of X-ray reflectivity, X-ray grazing incidence diffraction and atomic force microscopy (AFM) investigations indicate the formation of well ordered oxadiazole multilayers. The structure of the VD-multilayers is compared with that of Langmuir-Blodgett (LB) films and thermally treated LB-multilayers prepared from the same compound.},
  language  = {en}
}
@article{BrumaHamciucSchulzetal.1999,
  author    = {Bruma, Maria and Hamciuc, Elena and Schulz, Burkhard and K{\"o}pnick, Thomas and Stiller, Burkhard and Mercer, Frank W.},
  title     = {Synthesis of fluorinated poly(phenylquinoxaline-amide)s and study of thin films made therefrom},
  year      = {1999},
  abstract  = {A series of five fluorinated poly(phenylquinoxaline-amide)s were synthesized by a polycondensation reaction of a diacid chloride containing the hexafluoroisopropylidene (6F) group, namely 2,2-bis(p-chlorocarbonylphenyl)- hexafluoropropane, with various aromatic diamines incorporating two phenyl-substituted quinoxaline rings. These polymers were easily soluble in polar aprotic solvents such as N-methylpyrrolione (NMP), dimethylformamide (DMF), and tetrahydrofurane (THF), and showed a high thermal stability with decomposition temperatures above 400 °C and glass transition temperatures in the range of 260-290 Tg. Polymer solutions in NMP were processed into free-standing films that showed low dielectric constant values, in the range of 3.4-3.9, and good mechanical properties, with tensile strength in the range of 40-80 MPa and elongation to break in the range of 22-55\%. Very thin films, in the range of tens of nanometer, which were deposited onto silicon wafers exhibited very smooth surfaces, free of pinholes when studied by atomic force microscopy (AFM).},
  language  = {en}
}
@article{BrumaSchulzKoepnicketal.1999,
  author    = {Bruma, Maria and Schulz, Burkhard and K{\"o}pnick, Thomas and Stiller, Burkhard and Belomoina, Nataliya and Mercer, Frank W.},
  title     = {Synthesis and study of aromatic polyamides containing silicon and phenylquinoxaline rings in the main chain},
  year      = {1999},
  abstract  = {New poly(phenylquinoxaline-amide)s with silicon in the main chain have been prepared by polycondensation reaction of a diacid chloride, namely bis(p-chlorocarbonyl-phenyl)-diphenylsilane, with aromatic diamines containing one or two phenylquinoxaline rings separated by a flexible bridge such as ether or methylene. These polymers were easily soluble in polar aprotic solvents such as N-methylpyrrolidinone (NMP) and dimethylformamide (DMF) and showed high thermal stability with decomposition temperature being above 450°C and glass transition temperature in the range of 260- 304°C. Polymer solutions in NMP were processed into thin flexible films which exhibited very smooth surfaces, free of pinholes when studied by atomic force microscopy. The free-standing films showed a dielectric constant in the range of 3.6-3.7.},
  language  = {en}
}
@article{SavaBrumaSchulzetal.1997,
  author    = {Sava, Ion and Bruma, Maria and Schulz, Burkhard and Mercer, Frank W. and Belomoina, Nataliya},
  title     = {Synthesis and Properties of Silicon-containing Polyamides},
  year      = {1997},
  abstract  = {A series of aromatic polyamides incorporating silicon together with phenylquinoxaline or with hexafluoroisopropylidene groups has been synthesized by solution polycondensation of a silicon-containing diacid chloride with aromatic diamines having phenylquinoxaline rings or hexafluoroisopropylidene groups. These polymers are easily soluble in polar aprotic solvents, such as N-methylpyrrolidinone and dimethylformamide, and in tetrahydrofurane, and can be solution-cast into thin, transparent films having low dielectric constant, in the range of 3.26 to 3.68. These polymers show high thermal stability with decomposition temperature being above 400 °C and glass transition temperature in the range of 236 °C to 275 °C.},
  language  = {en}
}
@article{LavrenkoSchulzStrelinaetal.1997,
  author    = {Lavrenko, Peter N. and Schulz, Burkhard and Strelina, Irina A. and Okatova, Olga V.},
  title     = {Synthesis and molecular properties of new poly(naphthalene-1,3,4-oxadiazole)s},
  year      = {1997},
  abstract  = {Poly[(1,4-naphthalene)-2,5-diyl-1,3,4-oxadiazole] and poly[(2,6-naphthalene)-2,5-diyl-1,3,4-oxadiazole] have been synthesized and investigated in conc. H2S04, by the flow birefringence method in comparison with poly(1,4- phenylene)-2,5-diyl-1,3,4-oxadiazole]. Changes in conformation parameters and optical anisotropy of a chain unit induced by incorporation of the naphthalene groups into the macromolecule backbone have been evaluated.},
  language  = {en}
}
@article{FreydankJanietzSchulz1998,
  author    = {Freydank, Anke-Christine and Janietz, Silvia and Schulz, Burkhard},
  title     = {Synthesis and electrochemical characterization of new amphiphilic 1,3,4-oxadiazoles},
  year      = {1998},
  abstract  = {The electrochemical behaviour of new amphiphilic 1,3,4-oxadiazoles were studied by cyclic voltammetry. The influence of the supra- molecular structure on the redox behaviour in liquid or solid solutions, in Langmuir-Blodgett multilayers, and in amorphous films is investigated in detail. The reversible reduction of amphiphilic 2,5-diarylene- 1,3,4-oxadiazoles is significantly influenced by substituents in the para position of the phenylene ring. In the solid states the reduction peak potentials are shifted to more negative values compared to data measured in solution. This shift increases as the film thickness is increased. An influence of the supramolecular order in the solid films was not found. In-situ UV-vis spectroelectrochemistry of LB-multilayers deposited onto indium tin oxide (ITO) glass give evidence for the formation of radical anions in the highly ordered layer.},
  language  = {en}
}
@article{BrumaSchulzKoepnicketal.1999,
  author    = {Bruma, Maria and Schulz, Burkhard and K{\"o}pnick, Thomas and Stiller, Burkhard and Mercer, Frank W.},
  title     = {Study of thin films made from aromatic polyamides with silicon and phenylquinoxaline rings in the main chain},
  year      = {1999},
  abstract  = {Aromatic polyamides containing silicon and phenylquinoxaline rings in the main chain have been prepared by polycondensation reaction of a silicon-containing diacid chloride, namely bis(p-chlorocarbonylphenyl) -diphenylsilane, with various aromatic diamines having preformed phenylquinoxaline units. These polymers were easily soluble in polar aprotic solvents, such as N-methylpyrrolidinone (NMP) and dimethylformamide (DMF), and in tetrahydrofurane. They showed high thermal stability with decomposition temperature being above 450°C and glass transition temperature in the range of 253-304°C. Polymer solutions in NMP were processed into thin films having the thickness of tens of nanometer to 10 mm, by spin-coating onto glass plates or silicon wafers. The films had strong adhesion to substrates and exhibited very smooth surfaces, free of pinholes, in atomic force microscopy (AFM) studies. The free-standing films had dielectric constant in the range of 3.48-3.69. Thermal treatment of the films up to 350°C rendered them completely insoluble in organic solvents, while maintaining their smoothness and strong adhesion to the silicon substrate, and with no Tg in DSC experiments. Their FTIR spectra did not show any changes compared to the untreated films, meaning that polymers maintain their structural integrity at high temperature. {\´O} 1999 Elsevier Science S.A. All rights reserved.},
  language  = {en}
}
@article{LavrenkoOkatovaSchulz1998,
  author    = {Lavrenko, Peter N. and Okatova, Olga V. and Schulz, Burkhard},
  title     = {Stability and degradation of poly(p-pheneylene-1,3,4-oxadiazole) molecules in sulphuric acid},
  year      = {1998},
  abstract  = {The translational diffusion coefficient and intrinsic viscosity of poly(1,4-phenylene-1,3,4-oxadiazole) molecules in 96\% H2S04 have been determined at different stages of degradation of the molecules in acid solution at temperature ranging from 82 to 105 °C. The degradation rate constant, k, has been obtained from the change in the molecular weight, M, of the product degraded in solution with time at high temperature. The activation energy of the hydrolysis process was 103 ± 7 kJmol-1, which is smaller than that of aromatic polyamides in the same solvent. According to our hydrodynamic data, the degree of coiling of the molecules of degraded products does not differ from that of undegraded samples, and our conclusion was that the degradation is not accompanied with a noticeable change in the short- range interactions in the molecular chain and may be understood as a random chain scission.},
  language  = {en}
}
@article{BrumaSavaMerceretal.1998,
  author    = {Bruma, Maria and Sava, Ion and Mercer, Frank W. and Reddy, Victor N. and K{\"o}pnick, Thomas and Stiller, Burkhard and Schulz, Burkhard},
  title     = {Silicon-containing poly(amide-ether)s},
  year      = {1998},
  abstract  = {New aromatic poly(amide-ether)s (II) have been synthesized by solution polycondensation of various aromatic diamines having two ether bridges (I) with a diacid chloride containing silicon, namely bis(chlorocarbonylphenyl)- diphenyIsilane. These polymers are easy soluble in polar amidic solvents such as N-methylpyrrolidinone or dimethylformamide and can be cast into thin flexible films or coatings from such solutions. They show high thermal stability with initial decomposition temperature being above 400 °C. Their glass transition temperatures lie in the range of 220-250 °C, except for polymer He which did not show a clear Tg when heated in a differential scanning calorimetry experiment up to 300 °C. The large interval between the glass transition and decomposition temperatures of pnlymers Ia-Id could be advantageous for their processing via compression molding. The polymer coatings deposited by the spincoating, technique onto silicon wafers showed a very smooth, pinhole-free surface in atomic force microscopy investigations. The free-standing films of 20-30 mm thickness show low dielectric constant, in the range of 3.65-3.78, which is promising for future application as high performance dielectrics.},
  language  = {en}
}
@article{OrgzallLorenzMikatetal.1997,
  author    = {Orgzall, Ingo and Lorenz, Bernd and Mikat, J{\"u}rgen E. R. and Dietel, Reinhard and Knochenhauer, Gerald and Schulz, Burkhard},
  title     = {Raman and IR spectroscopic investigation of aromatic 1,3,4-oxadiazole polymers and oligomers},
  year      = {1997},
  abstract  = {The molecular structure of poly(p-phenylene-1,3,4-oxadiazole) (POD) is investigated using i.r. and Raman spectroscopy. Both methods reveal characteristic differences for the a- and b-POD forms that are most obvious in the spectral region between 1500 and 1650 cm-1. The spectra for dimer and tetramer compounds already show the same features as found for longer chains. Based on molecular modelling calculations these differences are assigned to cis and trans conformations of the main chain segments. High pressure measurements show a linear shift of the Raman lines and support the result of the thermodynamic stability of the trans conformation.},
  language  = {en}
}