Thermal- and Photo-Induced Phase-Transition Behaviors of a Tapered Dendritic Liquid Crystal with Photochromic Azobenzene Mesogens and a Bicyclic Chiral Center
A ribbon‐shaped chiral liquid crystalline (LC) dendrimer with photochromic azobenzene mesogens and an isosorbide chiral center (abbreviated as AZ3DLC) was successfully synthesized and its major phase transitions were studied by using differential scanning calorimetry (DSC) and linear polarized optic...
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Published in | Chemistry : a European journal Vol. 20; no. 19; pp. 5689 - 5695 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
WILEY-VCH Verlag
05.05.2014
WILEY‐VCH Verlag Wiley Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | A ribbon‐shaped chiral liquid crystalline (LC) dendrimer with photochromic azobenzene mesogens and an isosorbide chiral center (abbreviated as AZ3DLC) was successfully synthesized and its major phase transitions were studied by using differential scanning calorimetry (DSC) and linear polarized optical microscopy (POM). Its ordered structures at different temperatures were further identified through structure‐sensitive diffraction techniques. Based on the experimental results, it was found that the AZ3DLC molecule exhibited the low‐ordered chiral smectic (Sm*) LC phase with 6.31 nm periodicity at a high‐temperature phase region. AZ3DLC showed the reversible photoisomerization in both organic solvents and nematic (N) LC media. As a chiral‐inducing agent, it exhibited a good solubility, a high helical‐twisting power, and a large change in the helical‐twisting power due to its photochemical isomerization in the commercially available N LC hosts. Therefore, we were able to reversibly “remote‐control” the colors in the whole visible region by finely tuning the helical pitch of the spontaneously formed helical superstructures.
Remote‐controlled color: A ribbon‐shaped chiral dendritic liquid crystal was newly synthesized, and its thermal and photo‐induced phase behaviors were investigated with the combined techniques of the thermal, microscopic, and scattering methods (see figure). |
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Bibliography: | Global Ph.D Fellowship Program - No. 2013H1A2A1033907 Human Resource Training Project for Regional Innovation, Basic Science Research Program - No. 2013R1A1A2007238 LG Yonam Foundation ArticleID:CHEM201303924 Converging Research Center Program - No. 2013K001428 ark:/67375/WNG-KGXJ72SC-S BK21Plus Program, Korea istex:862EA51C3C8F3909F6A03CB89DBD8564D84014CB ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0947-6539 1521-3765 |
DOI: | 10.1002/chem.201303924 |