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Photoswitchable Smectic Liquid-Crystalline Elastomers

✍ Scribed by Patrick Beyer; Rudolf Zentel

Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
159 KB
Volume
26
Category
Article
ISSN
1022-1336

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✦ Synopsis

Abstract

Summary: We succeeded in the synthesis of azo side chain containing polysiloxanes with broad smectic C* and A phases. In these polymers the phase transition temperatures can be shifted reversibly by up to 17 °C by irradiation with UV (cis) or VIS (trans) light. Thin films of these polymers in the smectic phase (both on substrates and as free‐standing films) orient perfectly in a homeotropic manner. As a consequence, the azo chromophores do no longer absorb during a perpendicular illumination with light (dichroism). It is thus possible to crosslink these films photochemically to prepare “photoswitchable smectic LC elastomers”.

The trans‐cis isomerization in homeotropically oriented LC elastomers.

magnified imageThe trans‐cis isomerization in homeotropically oriented LC elastomers.

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