SYNTHESIS AND CHARACTERIZATION OF NOVEL CHIRAL SMECTIC C(Sc*) PHASE SHISH-KEBAB TYPE LIQUID CRYSTALLINE BLOCK COPOLYMERS* |
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Authors: | Shi-jun Zheng Zi-fa Li Shu-yuan Zhang Shao-kui Cao Ming-sheng Tang Qiu-jun Fen Qi-feng Zhou |
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Institution: | Department of Materials Engineering; Zhengzhou University; Zhengzhou 450052; China Department of Polymer Science and Engineering; College of Chemistry; Peking University; Beijing 100871; China |
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Abstract: | A new series of chiral shish-kebab type liquid crystal block copolymers that form the smecticC(Sc~*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC.DSC. TG, POM. X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whenthey were heated to their melting temperatures (T_m) and the copolymers 8 were in liquid crystal phase at roomtemperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM.All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiralsmectic C(Sc~*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal blockcopolymers that form a chiral smectic C(Sc~*) phase. The variation of melting and isotropization temperatureswith molecular structure was also discussed. |
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Keywords: | Shish-kebab type liquid crystal Block copolymers Chiral smectic C phase Synthesis and characterization |
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