Cholesteric star-shaped liquid crystals induced by a maltose core: synthesis and characteristics

Three esters of maltose (A1-A3) with 4-(4-(alkoxybenzoyloxy)phenoxy) -6-oxohexanoic acid (b1-b3) side-arms have been synthesised. All the maltose derivatives were laevo-rotationary, unlike their parent cores. The side arm b1 did not display liquid crystalline (LC) properties, and b2 and b3 displayed...

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Bibliographic Details
Published in:Liquid crystals 2010-11, Vol.37 (11), p.1373-1379
Main Authors: Tian, Mei, Zhang, Bao-Yan, Cong, Yue-Hua, He, Xiao-Zhi, Chu, Hui-Shu, Zhang, Xiao-Yu
Format: Article
Language:English
Subjects:
Chemical compounds
Chemical synthesis
cholesteric phase
Derivatives
Esters
Liquid crystal polymers
Liquid crystals
Maltose
Mesophase
Nematic
nematic arms
Phase transitions
star-shaped liquid crystal
Surface layer
Terminals
Texture
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Summary:Three esters of maltose (A1-A3) with 4-(4-(alkoxybenzoyloxy)phenoxy) -6-oxohexanoic acid (b1-b3) side-arms have been synthesised. All the maltose derivatives were laevo-rotationary, unlike their parent cores. The side arm b1 did not display liquid crystalline (LC) properties, and b2 and b3 displayed thermotropic nematic LC properties. The star-shaped compound (SSC) A1 with b1 side-arms did not display a mesomorphic phase. Unlike the nematic schlieren texture provided by side-arms b2 and b3, the star-shaped liquid crystals (SSLC) A2 and A3 displayed Grandjean and oily texture in the cholesteric phase. The results suggest that the LC properties of the side-arms have an important influence on the formation of LC properties in an SSC, and that the maltose core is important in determining the mesomorphic phase type. In other words, the SSC displayed LC properties only when the side-arms were also LC, and the maltose core induced a cholesteric phase in the SSLC with nematic side-arms. The mesomorphic regions for A2 and A3 were 39.1 and 53.7°C during the heating cycle and 63.8 and 107.0°C during the cooling cycle, respectively. The longer terminal chain rendered the mesomorphic region broader.
ISSN:0267-8292
1366-5855
DOI:10.1080/02678292.2010.517325