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  • 1
    Electronic Resource
    Electronic Resource
    Phase and orientational behaviors in liquid crystalline main-chain/side-group block copolymers (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 21-29 
    Details
    ISSN: 0887-6266
    Keywords: liquid crystal ; block copolymer ; polyester block ; polymethacrylate block ; magnetic field ; X-ray diffraction ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase and orientational behaviors of a series of liquid crystalline (LC) AB-type diblock copolymers comprising thermotropic main-chain (MC) polyester and side-group (SG) polymethacrylate blocks were investigated by X-ray diffraction. The MC and SG blocks were phase separated and gave rise to their individual mesophases that coexisted at equilibrium. The samples were oriented by using either a magnetic field or a mechanical field. In magnetically aligned samples both the MC and SG microphases were oriented with their smectic planes orthogonal to the magnetic field direction, independent of the copolymer composition. Mechanically aligned, fiber samples showed different orientations of the MC and SG smectic planes for different sample compositions. In this case the disposition of the smectic planes of the MC and SG blocks was driven by the relative length of the two blocks. Some features of the X-ray patterns of the copolymers were compared to those of the MC and SG homopolymers. In addition, the MC smectic domains crystallized on annealing without affecting the orientation that had been achieved by applying a magnetic field. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 21-29, 1998
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Phase transitions of side-group liquid crystalline polymers with a metastable SA phase (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 15 (1994), S. 7-13 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1994.030150103
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  • 3
    Electronic Resource
    Electronic Resource
    A phase polymorphism N—SAd—I in liquid-crystalline polymethacrylates with 4′-trifluoromethoxyazobenzene mesogenic side groupsDedicated to Prof. Dr. Jürgen Springer with best wishes on the occasion of his 60th birthday (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 16 (1995), S. 161-167 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mesophase behaviour of liquid-crystalline polymethacrylates with 4′-trifluoromethoxyazobenzene mesogens and alkylene spacers \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\rlap{--} ({\rm CH}_{\rm 2} \rlap{--} )_n ,n = 2 - 6} \right) $\end{document} in the side chains was investigated and compared with that of the corresponding non-fluorinated polymers. The fluorinated polymers with spacer lengths n = 5 and 6 are the first side-group liquid-crystalline polymethacrylates showing a nematic phase below a smectic A phase.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1995.030160302
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid crystalline networks of polymethacrylates (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 3427-3434 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: LC networks on the basis of methacrylate and dimethacrylate components were synthesized via bulk and precipitation copolymerization. Up to an amount of crosslinking component of 1 mol-% a smetic A phase is observed. The networks with 3 and 5 mol-% only show a nematic phase. From X-ray diffraction an orientation of the smectic phase was observed that derives from surface effects or biaxial swelling. It was found that the orientation can be increased by multiple swelling/deswelling cycles.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021971028
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of chirality on the phase behaviour of copolymers containing cholesterol as mesogenic moiety (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 1337-1348 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Liquid-crystalline side-group copolymers containing cholesterol and chiral nonmesogenic chloropropionate acid groups were synthesized and investigated by means of size-exclusion chromatography, proton nuclear magnetic resonance (1H NMR), polarization microscopy, X-ray diffraction and differential scanning calorimetry. In addition the spacers of the cholesterol-containing side groups were modified by substitution of two of the methylene groups by oxygen ether groups. The cholesterol-containing homopolymer displays only an SA-mesophase. Amounts of more than 50 mol-% of the non-mesogenic chiral co-compounds led to the total disappearance of liquid-crystalline phases. For less than 50 mol-% a different phase behaviour was observed for the copolymers with unsubstituted and ether-substituted spacers. Phase transition temperatures depend also on the chirality of the non-mesogenic groups. Similar results were obtained by investigating a copolymer system, which contains chiral camphor-10-sulfonic acid moieties and which was synthesized to check this observation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970413
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in liquid-crystalline phase behaviour of some poly[p-(methacryloyloxyalkyleneoxy)benzoate]s with bromination at the m-position in the mesogens (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 2015-2026 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structural properties of side-group liquid-crystalline polymers with large electronegative space-filling substituents at the mesogenic groups were investigated. The synthesis and characterization of some poly[m-bromo-p-(methacryloyloxyalkyleneoxy)benzoate]s are reported. Their liquid-crystalline properties were investigated using differential scanning calorimetry and X-ray diffraction techniques and were compared to some unsubstituted compounds found in the literature. A general decrease in the phase transition temperatures and in the order of the liquid-crystalline phases for the Br-substituted compounds was observed. It can be concluded that the liquid-crystalline properties of polymers with large side-group substituents at the mesogens can be maintained if long flexible or large electron-rich end groups are introduced.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930820
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  • 7
    Electronic Resource
    Electronic Resource
    New copolymethacrylates with azo-chromophores in the side chain (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 243-250 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis and characterization of new poly({6-[4-(4-cyanophenylcarbamoyl)phenoxy]hexyl methacrylate}-co-{6-[4-(4- cyanophenylazo)phenoxy]hexyl methacrylate}) are reported. Their liquid-crystalline properties are investigated using differential scanning calorimetry, polarizing microscopy and X-ray diffraction techniques. The glass transition temperatures and the clearing points can be influenced by variation of the copolymer composition. The substances offer a relatively broad temperature range of mesomorphic properties suitable for photochemical studies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940120
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  • 8
    Electronic Resource
    Electronic Resource
    Phase and thermal behavior of liquid-crystalline block copolymers (1996)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 7 (1996), S. 374-378 
    Details
    ISSN: 1042-7147
    Keywords: Liquid-crystalline block copolymer ; polyester block ; polymethacrylate block ; phase separation ; multiple endothermic behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The phase behavior of liquid - crystalline (LC) block copolymers containing mesomorphic blocks with main chain (MC) units and side-group (SG) substituents was investigated. The MC block consisted of an LC semiflexible polyester and the SG block was an LC polymethacrylate. Four different samples were prepared with the content of the SG blocks varying from 35 to 79 wt%. The thermal behavior of the copolymers was investigated using differential scanning calorimetry, and X-ray diffraction was used to characterize the phase structure. Both the MC and SG blocks formed smectic A and nematic mesophases. Thus, the occurrence of distinct and well-defined phase transitions clearly indicated that MC and SG blocks were phase-separated and showed their own phase behavior. Two different endothermic processes were identified in annealed samples that followed different kinetics. The low-temperature process is thought to involve the MC blocks in their own domains and was observed up to the smectic A to nematic transition temperature of these blocks. The hightemperature process involves the interface between MC and SG domains and is probably due to melting of crystallites grown during annealing. It is shown that the crystallization develops with kinetics affected by the degree of order of the LC state of the SG domains.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Influence of the mesophase structure on the β-relaxation in liquid crystalline poly(meth)acrylates (1996)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 7 (1996), S. 853-857 
    Details
    ISSN: 1042-7147
    Keywords: liquid crystalline polymethacrylates and polyacrylates ; dielectric spectroscopy ; X-ray experiments ; β-relaxation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dependence of the rotation of the mesogenic unit around its long axis (β-relaxation) on the actual mesophase in liqid crystalline polymethacrylates and polyacrylates was studied by dielectric spectroscopy in the frequency range from 10-2 Hz to 106 Hz and in a temperature range from 170 K to 430 K. As mesogenic units derivatives of (p-alkoxy-phenyl)-benzoate were used where different mesophases were achieved by small variation of the mesogenic structure, the spacer length and the tail group of the mesogenic unit. For all samples the temperature dependence of the relaxation rate of the β-relaxation can be described by an Arrhenius equation where both the pre-exponential factor and the activation energy increase significantly with the order of the mesophase. To characterize the structure X-ray measurements were also carried out. The mean lateral mesogenic distance was correlated directly with relaxational quantities.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New azo-dye containing side group copolymethacrylates (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1943-1949 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new type of side group copolymethacrylates was synthesized, characterized and tested with respect to its behavior on irradiation with an Ar+-laser beam. The side groups consist of methylene spacer units with different length and of three-ring mesogens with an ester group between the first and the second aromatic ring and on the other hand of two-ring mesogens with an azo-structure between the aromatic rings, respectively. The azochromophoric structure contains different substituents in the terminal aromatic ring. The homopolymers of the azo-dye containing monomers do not display liquid crystalline (lc) mesophases, but the three-ring mesogens induce lc-phases in opposition to the equimolaric copolymers with two-ring ester group mesogens. The lc phases are important for the stability of the recorded change of birefringence (photorecording process) which is influenced by irradiation of the polymers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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