The effects of molecular shape and quadrupole moment on tilted smectic phase formation

WITHERS, I. M., CARE, C., NEAL, M. P. and CLEAVER, D. J. (2002). The effects of molecular shape and quadrupole moment on tilted smectic phase formation. Molecular Physics, 100 (12), 1911-1924.

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Link to published version:: 10.1080/00268970210129274

Abstract

Results are presented from constant NPT Monte Carlo simulations of two systems based on the biaxial internally rotated Gay-Berne (IRGB) potential. First, the effect of increasing molecular elongation is considered, and it is shown that a change in aspect ratio from 3: 1 to 4: 1 leads to nematic and tilted smectic J phases being replaced by smectic A and tilted smectic G phases, respectively. Second, the effect of a longitudinal electric quadrupole on the phase behaviour of the IRGB model is examined. The presence of a moderate quadrupole moment results in the smectic G phase being replaced by a smectic J; the onset pressure of the smectic J increases monotonically as the quadrupole moment is increased, although the integrity of the tilted layers improves. In addition, the region of smectic A stability is found to persist for moderate quadrupole moment values. For the largest quadrupole moment considered, domains comprising poorly defined, tilted layers are formed but fail to develop into coherent smectic structures. This observation is ascribed to the competition between the unique tilt direction favoured by the biaxial IRGB potential and the random tilt direction of the uniaxial quadrupole-quadrupole interactions.

Item Type: Article
Research Institute, Centre or Group: Materials and Engineering Research Institute > Polymers Nanocomposites and Modelling Research Centre > Materials and Fluid Flow Modelling Group
Identification Number: 10.1080/00268970210129274
Depositing User: Hilary Ridgway
Date Deposited: 09 Apr 2010 14:51
Last Modified: 29 Sep 2010 10:52
URI: http://shura.shu.ac.uk/id/eprint/1536

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