Liquid Crystals

38. 1: Study of Ion Beam Alignment of Liquid Crystals on Polymer Substrates

by Kateryna Artyushkova

Flexoelectric and elastic coefficients of odd and even homologous bimesogens

by Flynn Castles

Published in 'Physical Review E' [copyright (2012) American Physical Society].

Katie L. Atkinson, Stephen M. Morris, Flynn Castles, Malik M. Qasim, Damian J. Gardiner, and Harry J. Coles
more Katie L. Atkinson, Stephen M. Morris, Flynn Castles, Malik M. Qasim, Damian J. Gardiner, and Harry J. Coles

Official link: http://link.aps.org/doi/10.1103/PhysRevE.85.012701
PDF: http://www.eng.cam.ac.uk/~fc252/PRE_85_012701_2012.PDF

It is known that bimesogenic liquid crystals exhibit a marked “odd-even” effect in the flexoelastic ratio (the effective flexoelectric coefficient to the average elastic coefficient), with the ratio being higher for the “odd-spaced” bimesogens (those with an odd number of alkyl groups in the spacer chain) than their neighboring even-spaced counterparts. To determine the contribution of each property to the flexoelastic ratio, we present experimental results on the flexoelectric and elastic coefficients of two homologous nonsymmetric bimesogens which possess odd and even alkyl spacers. Our results show that, although there are differences in the flexoelectric coefficients, there are substantially larger differences in the effective elastic coefficient. Specifically, the odd bimesogen is found to have both a low splay elastic coefficient and a very low bend elastic coefficient which, when combined, results in a significantly lower effective elastic coefficient and consequently a higher flexoelastic ratio.

Flying Geese as Moving Targets: Are Korea and Taiwan Catching Up with Japan in Advanced Displays?

by Jeffrey Hart

(with Greg Linden, Stefanie Ann Lenway, and Thomas P. Murtha) Industry and Innovation, 5 (June 1998), 11-34.

Display's the Thing: The Real Stakes In the Conflict Over High-Resolution Displays

by Jeffrey Hart

(with Michael Borrus) Journal of Policy Analysis and Management, 13 (Winter 1994), pp. 21-54.

The Anti‐dumping Petition of the Advanced Display Manufacturers of America: Origins and Consequences

by Jeffrey Hart

published in The World Economy, 16 (January 1993), 85-109.

Imidazoliums supramoléculaires aux propriétés ajustables

by William Dobbs

Fast-switching phase gratings using in-plane addressed short-pitch polymer stabilized chiral nematic liquid crystals

by Flynn Castles

Published in 'Applied Physics Letters' [copyright (2011) American Institute of Physics].

S. M. Morris, D. J. Gardiner, F. Castles, P. J. W. Hands, T. W. Wilkinson, and H. J. Coles

Official link:... more S. M. Morris, D. J. Gardiner, F. Castles, P. J. W. Hands, T. W. Wilkinson, and H. J. Coles

Official link: http://dx.doi.org/10.1063/1.3670041
PDF: http://www.eng.cam.ac.uk/~fc252/APL_99_253502_2011.PDF

We demonstrate a fast-switching (sub-millisecond) phase grating based upon a polymer stabilized short-pitch chiral nematic liquid crystal that is electrically addressed using in-plane electric fields. The combination of the short-pitch and the polymer stabilization enables the diffraction pattern to be switched “on” and “off” reversibly in 600 µs. Results are presented on the far-field diffraction pattern along with the intensity of the diffraction orders as a function of the applied electric field and the response times.

Modification in dielectric properties of SWCNT doped ferroelectric liquid crystals

by Swadesh Kumar Gupta

Dielectric Relaxation Study of Two Different Mesogenic Cinnamates with a Substituted Ethyl Terminal Chain

by Swadesh Kumar Gupta

Creep and stress relaxation in a longitudinal polymer liquid crystal: Prediction of the temperature shift factor

by Nandika D'Souza

Yan Jun Liu*, Qingzhen Hao*, Joseph S. T. Smalley, Justin Liou, Iam Choon Khoo, and Tony Jun Huang, A Frequency-Addressed Plasmonic Switch Based on Dual-Frequency Liquid Crystal, Applied Physics Letters, Vol. 97, 091101, 2010 (*equal contributions) (featured as front cover image).

by Joseph Smalley

Cholesteric colloidal liquid crystals from phytosterol rod-like particles

by Laura Rossi

New Low Molar Mass Organosiloxanes With Unusual Ferroelectric Properties

by Hywel Owen

A new low molar mass chiral organosiloxane mesogen and its racemic analogue have been synthesized and their... more A new low molar mass chiral organosiloxane mesogen and its racemic analogue have been synthesized and their mesomorphic and ferroelectric properties investigated. The chiral derivative, denoted AB, exhibits one tilted enantiotropic ferroelectric smectic C mesophase over a broad temperature range, with very high tilt angles and moderate spontaneous polarization (36° and 19 nC cm−2 at 20°C). The achiral siloxane derivative, denoted AB, exhibits one broad enantiotropic smectic C phase. Preliminary electro-optic measurements indicate that the spontaneous polarization is weakly dependent on temperature between 10°C and 50°C, the latter being the Sc to isotropic phase transition. The tilt angle and layer spacing are temperature independent, and current response times of less than 200 μs were measured at 25°C for fields of 10 V μ−1. These results are discussed in comparison with those for side chain polymer liquid crystal structures and other low molar mass ferroelectric materials.

The limits of flexoelectricity in liquid crystals

by Flynn Castles

Published in 'AIP Advances' [copyright (2011) Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.]

F. Castles, S. M. Morris, and H. J. Coles

Official link: more F. Castles, S. M. Morris, and H. J. Coles

Official link: http://link.aip.org/link/?ADV/1/032120
PDF: http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=AAIDBI000001000003032120000001&idtype=cvips&doi=10.1063/1.3624725&prog=normal


The flexoelectric conversion of mechanical to electrical energy in nematic liquid crystals is investigated using continuum theory. Since the electrical energy produced cannot exceed the mechanical energy supplied, and vice-versa, upper bounds are imposed on the magnitudes of the flexoelectric coefficients in terms of the elastic and dielectric coefficients. For conventional values of the elastic and dielectric coefficients, it is shown that the flexoelectric coefficients may not be larger than a few tens of pC/m. This has important consequences for the future use of such flexoelectric materials in devices and the related energetics of distorted equilibrium structures.

Pyrrolidinium Ionic Liquid Crystals With Pendant Mesogenic Groups

by Peter Nockemann

Imidazolium and Pyrrolidinium Ionic Metallomesogens with Pendant Mesogenic Groups

by Peter Nockemann

Imidazolium Ionic Liquid Crystals With Pendant Mesogenic Groups

by Peter Nockemann

Rigid Tetracatenar Liquid Crystals Derived From 1, 10-Phenanthroline

by Peter Nockemann

Imidazo [4, 5-F]-1, 10-Phenanthrolines: Versatile Ligands for the Design of Metallomesogens

by Peter Nockemann

Lanthanide-Containing Metallomesogens With Low Transition Temperatures

by Peter Nockemann