Dyes in Liquid Crystals: Experimental and Computational Studies of a Guest-Host System Based on a Combined DFT and MD Approach

TY - JOUR

T1 - Dyes in Liquid Crystals

T2 - Experimental and Computational Studies of a Guest-Host System Based on a Combined DFT and MD Approach

AU - Sims, Mark T.

AU - Abbott, Laurence C.

AU - Cowling, Stephen J.

AU - Goodby, John W.

AU - Moore, John N.

N1 - © 2015 The Authors. This content is made available by the publisher under a Creative Commons CC BY Licence

PY - 2015/7/6

Y1 - 2015/7/6

N2 - Practical applications of guest-host liquid crystal systems are critically dependent on the alignment of the guest species within the liquid crystal host. UV/Vis absorption spectroscopy shows that the 1,5-dihydroxy-2,6-bis-(4-propylphenyl)-9,10-anthraquinone dye aligns within the E7 nematic host, giving an experimental dichroic ratio of 9.40 and dye order parameter of 0.74. This alignment was modelled by using a combination of density functional theory (DFT) and molecular dynamics (MD) computational approaches that do not require the input of experimental data. Time-dependent DFT calculations show that the electronic transition dipole moment is highly aligned with the long molecular axis of the dye. Fully atomistic MD simulations show that the long axis of the dye is less highly aligned within the E7 host, indicating that this contribution limits the overall dye alignment and, thereby, the potential practical applications of this particular system. Importantly, this study demonstrates an experimental and combined DFT and MD computational approach that may be applied generally to guest-host systems, providing a potential route to their rational design. Model guest: A guest anthraquinone dye that aligns within a nematic liquid crystal host is modelled by a combined computational approach. DFT calculations give the alignment of the transition dipole moment within the dye, and fully atomistic MD simulations model the alignment of the dye within the host.

AB - Practical applications of guest-host liquid crystal systems are critically dependent on the alignment of the guest species within the liquid crystal host. UV/Vis absorption spectroscopy shows that the 1,5-dihydroxy-2,6-bis-(4-propylphenyl)-9,10-anthraquinone dye aligns within the E7 nematic host, giving an experimental dichroic ratio of 9.40 and dye order parameter of 0.74. This alignment was modelled by using a combination of density functional theory (DFT) and molecular dynamics (MD) computational approaches that do not require the input of experimental data. Time-dependent DFT calculations show that the electronic transition dipole moment is highly aligned with the long molecular axis of the dye. Fully atomistic MD simulations show that the long axis of the dye is less highly aligned within the E7 host, indicating that this contribution limits the overall dye alignment and, thereby, the potential practical applications of this particular system. Importantly, this study demonstrates an experimental and combined DFT and MD computational approach that may be applied generally to guest-host systems, providing a potential route to their rational design. Model guest: A guest anthraquinone dye that aligns within a nematic liquid crystal host is modelled by a combined computational approach. DFT calculations give the alignment of the transition dipole moment within the dye, and fully atomistic MD simulations model the alignment of the dye within the host.

KW - density functional calculations

KW - dyes/pigments

KW - liquid crystals

KW - molecular dynamics

KW - UV/Vis spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=84933524456&partnerID=8YFLogxK

U2 - 10.1002/chem.201406372

DO - 10.1002/chem.201406372

M3 - Article

AN - SCOPUS:84933524456

SN - 0947-6539

VL - 21

SP - 10123

EP - 10130

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 28

ER -