Skip to main content Accessibility help
×
Home

Molecular Dynamics Simulation Of A Cyclic Siloxane Based Liquid Crystalline Material

  • Soumya S. Patnaik (a1), Ruth Pachter (a2), Steve Plimpton (a3) and W. WADE ADAMS (a2)

Abstract

We have used molecular dynamics (MD) to study the room temperature bulk phase behavior of a cyclic siloxane with a pentamethylcyclosiloxane core and biphenyl-4-allyloxybenzoate Mesogens (BCS). This Material exhibits thermotropic liquid crystalline behavior above 120 °C. Bonded and non-bonded interactions were considered and a Molecular Mechanics force field was used to model the structural anisotropy of the siloxane Molecules. Molecular clusters with and without periodic boundary conditions (pbc) were studied to investigate the effect of the finite system size on the time evolution of the molecular structure. The precise nature of the boundary conditions was found to be significant and simulations that exclude pbc were better able to model the molecular system. It was found that molecular shapes associated with low energy conformations were not cylindrically symmetric but more splayed like. An approximate measure of the shape of the mesogens was obtained by describing ellipsoids around the Mesogens, and estimating the molecular length, breadth, and width from the principal axes of the ellipsoids. The orientational order was then calculated by defining the molecular axis to be along the major principal axis.

Copyright

References

Hide All
1. Bunning, T.J., McNamee, S.G., McHugh, C.M., Patnaik, S.S., Ober, C.K., and Adams, W.W. in Applications of Synchrotron Radiation Techniques to Materials Science, edited by Perry, D.L., Shinn, N.D., Stockbauer, R.L., D'Amico, K.L. and Terminello, L.J. (Mater. Res. Soc. Proc. 307, Pittsburgh, PA, 1993) pp. 311316.
2. Patnaik, S.S., Pachter, R., Bunning, T.J., Crane, R.L. and Adams, W.W., to appear in Liquid Crystals.
3. Allen, M.P., Frenkel, D. and Talbot, J., Computer Physics Reports 9, 301 (1989).
4. Frenkel, D. in Phase Transitions in Liquid Crystals, edited by Martelluci, S. and Chester, A.N. (Plenum Press, New York, 1992) p.67.
5. Eppenga, R. and Frenkel, D., Mol. Phys. 52 (6), 1303 (1984).
6. Wilson, M.R. and Allen, M.P., Mol. Cryst. Liq. Cryst., 198, 465 (1991).
7. Wilson, M.R. and Allen, M.P., Liq. Cryst. 12 (1), 157 (1992).
8. Plimpton, S.J., Hendrickson, B.A., and Heffelfinger, G.S. in Proceedings of 6th SIAM Conference on Parallel Processing for Scientific Computing, (SIAM, Philadelphia, PA, 1993) p.178.
9. Brooks, B.R., Bruccoleri, R.E., Olafson, B.D., States, D.J., Swaminathan, S. and Karplus, M., J. of Comp. Chem. 4 (2), 187 (1993).
10. QUANTA is a Molecular Modeling package developed by Molecular Simulation Inc., Waltham, MA 02154. The parameters of version 2.2 (1993) were used.
11. Ober, C.K., McNamee, S.G., McHugh, C.M., Bunning, T.J., Patnaik, S.S. and Adams, W.W., presented at the APS March Meeting, Seattle, WA, 1993 (unpublished).

Molecular Dynamics Simulation Of A Cyclic Siloxane Based Liquid Crystalline Material

  • Soumya S. Patnaik (a1), Ruth Pachter (a2), Steve Plimpton (a3) and W. WADE ADAMS (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed