Computer simulation of polar bent-core molecules

Johnston, Stephen, Low, Robert J. and Neal, Maureen P. (2002) Computer simulation of polar bent-core molecules. Physical Review E, 66 (6). 061702. ISSN 2470-0053

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Abstract

Results are presented from molecular dynamics simulations in the NPT ensemble of novel bent-core liquid crystal systems. Following on from a previous study of bent-core steric shape, this study examines the effect the addition of a transverse electric dipole has on the phase diagram of a bent-core liquid crystal model. A simple model of the interaction employed a two-site Gay-Berne potential with the sites separated by ±0.5 reduced units with a central transverse point dipole, for all models investigated. The angle between the sites 180°-γ was varied in a range γ=10° to γ=70° suggested by real molecules. The addition of the dipole to the model tended to stabilize smectic phases and increase the angle of tilted phases. As the angle γ increased, the transition temperature to the first ordered phase decreased markedly. Smectic A, tilted smectic B, and a spontaneously polarized smectic B phases were observed in the γ=10° bent-core model. The γ=20° model showed smectic A and tilted antiferroelectric smectic B phases. The γ=40° model showed an antiferroelectric phase that exhibited unusual packing behavior. Both the γ=20° and γ=40° models demonstrated a significant phase biaxiality in the smectic B phases.