Synthesis of a series of liquid crystalline photosensitive monomers, with azo-group used as a connecting link in central parts of the molecules, has been successfully proposed and experimentally optimized. These substances form in their basic state the stable isomer (E). When being irradiated they pass to the less stable isomer (Z), but after the irradiation is stopped, they spontaneously pass to the basic state. This reverse process was studied by nuclear magnetic resonance spectroscopy and by high-pressure liquid chromatography. Some of the prepared materials revealed an extraordinarily long time of life of the less stable isomers, up to several days, which enables a more detailed study of their dielectric and liquid crystalline characteristics. First from those monomers, with acrylate ending group, was yet used for preparation and study of polymer, in collaboration with professor Shibaev΄s laboratory on Moscow State University. |
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