Issue
EPL
Volume 88, Number 2, October 2009
Article Number 26003
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/88/26003
Published online 05 November 2009
EPL, 88 (2009) 26003
DOI: 10.1209/0295-5075/88/26003

Polymeric-nanoparticles–induced vertical alignment in ferroelectric liquid crystals

A. Kumar1, J. Prakash1, P. Goel1, T. Khan2, S. K. Dhawan2, P. Silotia3 and A. M. Biradar1

1   Liquid Crystal Group, National Physical Laboratory - Dr. K. S. Krishnan Road, New Delhi-110012, India
2   Conducting Polymer Group, National Physical Laboratory - Dr. K. S. Krishnan Road, New Delhi-110012, India
3   Department of Physics and Astrophysics, University of Delhi - Delhi-110007, India

abiradar@mail.nplindia.ernet.in

received 13 July 2009; accepted in final form 5 October 2009; published October 2009
published online 5 November 2009

Abstract
Here, we report the polymeric (copolymer of benzene and pentacene) nanoparticles (PNPs) induced vertical alignment in ferroelectric liquid crystals (FLCs). The nanoparticles used in this study have been synthesized via chemical route method. The PNPs have been doped in FLC mixture. It has been observed that pentacene molecules (presented in PNPs used) prefer an upright orientation on the indium-tin-oxide–coated surfaces, which in turn provide assistance to align FLC molecules vertically (or homeotropically). It has also been observed that the addition of PNPs into the FLC materials improves the electro-optical response. However, the transition temperatures of the PNPs-doped FLC materials have been lowered. These findings will provide a fascinating tool to align FLC materials devoid of any surface treatment. Moreover, these studies would be helpful in the realization of low threshold and faster liquid crystal display devices.

PACS
61.30.-v - Liquid crystals.
77.84.Nh - Liquids, emulsions and suspensions; liquid crystals.
42.79.Kr - Display devices, liquid-crystal devices.

© EPLA 2009