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Photoswitchable Smectic Liquid‐Crystalline Elastomers
Author(s) -
Beyer Patrick,
Zentel Rudolf
Publication year - 2005
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200500093
Subject(s) - elastomer , isomerization , chromophore , materials science , homeotropic alignment , polymer , photoisomerization , side chain , phase (matter) , liquid crystal , phase transition , liquid crystalline , polymer chemistry , photochemistry , composite material , chemistry , organic chemistry , optoelectronics , catalysis , physics , quantum mechanics
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.