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Manipulation of the ferroelectricity in LC polymers via photomechanical isomerization of azobenzene moieties
Author(s) -
Öge Tanja,
Zentel Rudolf
Publication year - 1996
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/macp.1996.021970602
Subject(s) - azobenzene , chromophore , isomerization , photoisomerization , mesogen , photochemistry , ferroelectricity , polymer , side chain , liquid crystal , copolymer , polymer chemistry , chemistry , materials science , phase (matter) , liquid crystalline , organic chemistry , optoelectronics , catalysis , dielectric
We report the synthesis and characterization of a new ferroelectric liquid crystalline side chain copolymer containing photoisomerizable chromophores and non‐photoisomerizable mesogenic units. On illumination with UV‐light a suppression of the polar order is obtained as indicated by a substantial drop of the spontaneous polarization ( P S ) compared to the dark state. We interpret this as the phase order being disrupted by the cis ‐isomer of the chromophore. After illumination with VIS‐light only the major part of P s is restored. The photochemical cis‐trans back‐isomerization (restoration of the phase) leads to a different stationary state than the dark state of the material. The thermal reisomerization ( cis‐trans ) in the liquid‐crystalline phase was observed to be faster than in solution by one order of magnitude.