Poly(phenylenevinylene)-based conjugated polymers with azobenzene groups in the main chains were prepared by the Pd-catalyzed coupling polymerization of divinylarenes with dihaloarenes. The Pd-catalyzed coupling polymerization of 4,4Јdivinylazobenzene with dihaloarenes such as 1,3-dibromobenzene, 1,
Manipulation of the ferroelectricity in LC polymers via photomechanical isomerization of azobenzene moieties
✍ Scribed by Tanja Öge; Rudolf Zentel
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 384 KB
- Volume
- 197
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
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.
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