The interplay of bent-shape, lateral dipole and chirality in thiophene based di-, tri-, and tetracatenar liquid crystals

被引:77
作者
Eichhorn, SH
Paraskos, AJ
Kishikawa, K
Swager, TM [1 ]
机构
[1] MIT, Dept Chem, Cambridge, MA 02139 USA
[2] MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA
关键词
D O I
10.1021/ja0268027
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
A range of mesogenic molecules varying in both bend angle and strength of lateral dipole were synthesized, and their phase behavior was characterized by polarizing microscopy, thermal analysis, X-ray diffraction, and electrooptical measurements. We find the general destabilization of the liquid crystallinity caused by strong lateral dipolar groups and the bent molecular shape are off-set in mesomorphic tetracatenars, which display stable nematic, smectic, columnar, and cubic mesophases. The broad mesomorphism of the tetracatenars containing lateral dipoles and their incompatibility with chiral induction are explained by considering that loosely correlated dimers exist within the mesophases. Chiral mesophases of derivatives with strong lateral dipoles were achieved by attaching fewer or different side chains to each end of the mesogen.
引用
收藏
页码:12742 / 12751
页数:10
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