The sterically induced packing of bent-shape molecules (so called “banana liquid crystals”) forms unique smectic phases, which have no counterpart in conventional calamitic liquid crystals. The structural features of the new mesophases observed from these non-chiral molecules may lead to unusual physical properties such as spontaneous polar ordering, superstructural (layer) chirality, supramolecular chirality, and modulated/undulated layer structures. We study structures, spontaneous desymmetrisation and transitions of the phase, and optical / electro-optical responses of this type of materials based on the Synchrotron x-ray diffraction, polarizing optical microscopy, and electro-optical measurement studies.

Selected Publications


1. Thermotropic uniaxial and biaxial nematic and smectic phases in bent-core mesogens, V. Prasad, S.-W. Kang, K.A. Suresh, L. Joshi, Q. Wang, and S. Kumar, J. Am. Chem. Soc. 127, 17224-17227 (2005).

2. Photo-responsive and electrically switchable mesophases in a novel class of achiral bent-core azo compounds, V. Prasad, S.-W. Kang, and S. Kumar, J. Mat. Chem., 14, 1495 (2004).

3. The Bent-Core Biaxial Nematic Phase, B. R. Acharya, A. Primak, S. Kumar, Invited Article, Liquid Crystal Today, 13, 1 (2004).

4. A Biaxial Nematic Phase Exhibited by Bent-core Molecules, B.R. Acharya, A. Primak, and S. Kumar, Phys. Rev. Lett, 92, 145506 (2004).

5. The elusive thermotropic biaxial nematic phase in rigid bent-core molecules, B. R. Acharya, A. Primak, T. J. Dingemans, E. T. Samulski, and S. Kumar, Pramana, 61, 231 (2003).

5. Bent-Core Liquid Crystal Materials

Project List: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11