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Thermal phase behavior of homologous liquid crystalline side group polyesters in dependence on the polymethylene main chain spacer length
Author(s) -
Emmerling Uwe,
Diele Siegmar,
Schmalfuß Heiko,
Werner Johannes,
Kresse Horst,
Lindau Jürgen
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980801)199:8<1529::aid-macp1529>3.0.co;2-6
Subject(s) - mesogen , liquid crystal , polyester , homologous series , differential scanning calorimetry , materials science , side chain , polymer chemistry , crystallography , phase (matter) , chemistry , polymer , organic chemistry , liquid crystalline , composite material , thermodynamics , physics , optoelectronics
With the aim to investigate the influence of a systematic variation of the length of flexible non‐mesogenic main chain segments on the mesomorphic properties a series of new liquid crystalline polyesters with 4‐(4‐nitrobenzyloxy)biphenyl moieties as mesogenic side groups was prepared. The mesomorphic and dynamic behavior were investigated by means of differential scanning calorimetry (DSC), X‐ray measurements, polarization microscopy and dielectric spectroscopy. All polyesters exhibit nematic and different smectic phases. Some of the homologues show “re‐entrant” nematic phases. The clearing point decreases at first with increasing main chain spacer length and passes through a minimum. From the results it was possible to propose packing models of the smectic phases with low order.