We thank the Defence Research and Development Organization for funding and Council of Scientific and Industrial Research for research fellowships. This work is contribution No. 248 from NIIST. Supporting Information is available online from Wiley InterScience or from the authors.
Manifestation of a Chiral Smectic C Phase in Diphenylbutadiene-Cored Bolaamphiphilic Sugars†
Article first published online: 12 JUN 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 18, Issue 11, pages 1632–1640, June 11, 2008
How to Cite
Das, S., Gopinathan, N., Abraham, S., Jayaraman, N., Singh, M. K., Prasad, S. K. and Rao, D. S. S. (2008), Manifestation of a Chiral Smectic C Phase in Diphenylbutadiene-Cored Bolaamphiphilic Sugars. Adv. Funct. Mater., 18: 1632–1640. doi: 10.1002/adfm.200701181
- Issue published online: 12 JUN 2008
- Article first published online: 12 JUN 2008
- Manuscript Revised: 18 DEC 2007
- Manuscript Received: 13 OCT 2007
- amphiphilic materials;
- liquid crystals;
- chiral materials;
A series of symmetrical bolaamphiphiles possessing a diphenylbutadiene core and glucopyranoside head groups linked together by oligomethylene spacers, were synthesized and their thermotropic liquid crystalline properties investigated by polarized light optical microscopy, differential scanning calorimetry, X-ray diffraction and electro-optic switching. In spite of the presence of chiral centers, amphiphilic sugars in general do not exhibit macroscopic chirality and this phenomenon is attributed to strong hydrogen bonding between sugar head groups resulting in microphase-segregated layer like arrangements. In the present study all the molecules investigated exhibited the smectic C* phase, i.e., tilted lamellar phase with macroscopic chiral ordering of the molecules. The stability of this phase increased with increase in the length of the oligomethylene spacers. Whereas for derivatives with spacers containing ≤4 methylene groups, the smectic C* phase was observed only in the cooling phase, for those containing spacers with ≥5 methylene groups this phase was observed both in the heating and cooling cycles. The absorption and fluorescence spectra of these materials suggest that the unusual observation of macroscopic chirality in these bolaamphiphiles containing free hydroxyl groups could be attributed to self-aggregating behavior of the diphenylbutadiene core.