Formation of smectic phases in binary liquid crystal mixtures with a huge length ratio

Beilstein Journal of Organic Chemistry

Robert P. Lemieux¹  C. Scott Hartley¹  Jeffrey C. Roberts¹  Friederike Knecht²  Frank Giesselmann²  Nadia Kapernaum² 

[1] Department of Chemistry, Queen’s University, Kingston, Ontario, Canada;Institut für Physikalische Chemie, Universität Stuttgart, D-70569 Stuttgart, Germany;

关键词: bidispersity;    liquid crystals;    phase diagrams;    smectic phases;    smectic F phase;    structure and dynamics;   

DOI  :  10.3762/bjoc.8.124

来源: DOAJ

【 摘 要 】

A system of two liquid-crystalline phenylpyrimidines differing strongly in molecular length was studied. The phase diagram of these two chemically similar mesogens, with a length ratio of 2, was investigated, and detailed X-ray diffraction and electrooptical measurements were performed. The phase diagram revealed a destabilization of the nematic phase, which is present in the pure short compound, while the smectic state was stabilized. The short compound forms smectic A and smectic C phases, whereas the longer compound forms a broad smectic C phase and a narrow higher-ordered smectic phase. Nevertheless, in the mixtures, the smectic C phase is destabilized and disappears rapidly, whereas smectic A is the only stable phase observed over a broad concentration range. In addition, the smectic translational order parameters as well as the tilt angles of the mixtures are reduced. The higher-ordered smectic phase of the longer mesogen was identified as a smectic F phase.

【 授权许可】

Unknown