Systematic coarse graining of 4-Cyano-4′-pentylbiphenyl

Grigorios Megariotis, Antonia Vyrkou, Adrien Leygue, Doros N. Theodorou

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

A coarse-grained model is derived for a liquid-crystal-forming molecule, 4-cyano-4′-pentylbiphenyl (5CB), from a detailed atomistic model using the iterative Boltzmann inversion (IBI) method in the isotropic phase at 315 K and 1 bar. The coarse-grained model consists of five "superatoms" (one for the cyano group, two for the aromatic rings in the biphenyl moiety, and two for the alkyl tail), which are categorized as three types. A modification of IBI, wherein only one of the effective intermolecular potentials (the one corresponding to the superatom pair whose intermolecular correlation function exhibits the highest deviation from the atomistic one) is updated at each iteration, proves to be necessary to achieve convergence. The coarse-grained model, which enables a savings of a factor of 35 in computational cost relative to atomistic simulation, is used to explore ordering into liquid-crystalline phases at lower temperatures. It is found to yield a first-order ordering transition at 288 K with small hysteresis and negligible system size effects. A detailed investigation in terms of various structural and dynamical measurements indicates that the ordered phase is of the smectic type rather than nematic, as observed experimentally. The ordering temperature can be brought close to the experimental value of 308.5 K through the simple rescaling of the intermolecular effective interaction potentials employed in the coarse-grained model. A nematic ordered phase can be obtained from the coarse-grained model by scaling up the head-head and tail-tail effective interaction potentials obtained by IBI.

Original languageEnglish
Pages (from-to)546-556
Number of pages11
JournalIndustrial and Engineering Chemistry Research
Volume50
Issue number2
DOIs
Publication statusPublished - 19 Jan 2011
Externally publishedYes

Fingerprint

Liquid Crystals
Liquid crystals
Hysteresis
4-cyano-4'-pentylbiphenyl
Crystalline materials
Temperature
Molecules
Liquids
Costs
diphenyl

Cite this

Megariotis, Grigorios ; Vyrkou, Antonia ; Leygue, Adrien ; Theodorou, Doros N. / Systematic coarse graining of 4-Cyano-4′-pentylbiphenyl. In: Industrial and Engineering Chemistry Research. 2011 ; Vol. 50, No. 2. pp. 546-556.
@article{1eac39ae56e74dc79ec8d2ccad7e7d24,
title = "Systematic coarse graining of 4-Cyano-4′-pentylbiphenyl",
abstract = "A coarse-grained model is derived for a liquid-crystal-forming molecule, 4-cyano-4′-pentylbiphenyl (5CB), from a detailed atomistic model using the iterative Boltzmann inversion (IBI) method in the isotropic phase at 315 K and 1 bar. The coarse-grained model consists of five {"}superatoms{"} (one for the cyano group, two for the aromatic rings in the biphenyl moiety, and two for the alkyl tail), which are categorized as three types. A modification of IBI, wherein only one of the effective intermolecular potentials (the one corresponding to the superatom pair whose intermolecular correlation function exhibits the highest deviation from the atomistic one) is updated at each iteration, proves to be necessary to achieve convergence. The coarse-grained model, which enables a savings of a factor of 35 in computational cost relative to atomistic simulation, is used to explore ordering into liquid-crystalline phases at lower temperatures. It is found to yield a first-order ordering transition at 288 K with small hysteresis and negligible system size effects. A detailed investigation in terms of various structural and dynamical measurements indicates that the ordered phase is of the smectic type rather than nematic, as observed experimentally. The ordering temperature can be brought close to the experimental value of 308.5 K through the simple rescaling of the intermolecular effective interaction potentials employed in the coarse-grained model. A nematic ordered phase can be obtained from the coarse-grained model by scaling up the head-head and tail-tail effective interaction potentials obtained by IBI.",
author = "Grigorios Megariotis and Antonia Vyrkou and Adrien Leygue and Theodorou, {Doros N.}",
year = "2011",
month = "1",
day = "19",
doi = "10.1021/ie901957r",
language = "English",
volume = "50",
pages = "546--556",
journal = "Industrial & Engineering Chemistry Research",
issn = "0888-5885",
publisher = "American Chemical Society",
number = "2",

}

Systematic coarse graining of 4-Cyano-4′-pentylbiphenyl. / Megariotis, Grigorios; Vyrkou, Antonia; Leygue, Adrien; Theodorou, Doros N.

In: Industrial and Engineering Chemistry Research, Vol. 50, No. 2, 19.01.2011, p. 546-556.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Systematic coarse graining of 4-Cyano-4′-pentylbiphenyl

AU - Megariotis, Grigorios

AU - Vyrkou, Antonia

AU - Leygue, Adrien

AU - Theodorou, Doros N.

PY - 2011/1/19

Y1 - 2011/1/19

N2 - A coarse-grained model is derived for a liquid-crystal-forming molecule, 4-cyano-4′-pentylbiphenyl (5CB), from a detailed atomistic model using the iterative Boltzmann inversion (IBI) method in the isotropic phase at 315 K and 1 bar. The coarse-grained model consists of five "superatoms" (one for the cyano group, two for the aromatic rings in the biphenyl moiety, and two for the alkyl tail), which are categorized as three types. A modification of IBI, wherein only one of the effective intermolecular potentials (the one corresponding to the superatom pair whose intermolecular correlation function exhibits the highest deviation from the atomistic one) is updated at each iteration, proves to be necessary to achieve convergence. The coarse-grained model, which enables a savings of a factor of 35 in computational cost relative to atomistic simulation, is used to explore ordering into liquid-crystalline phases at lower temperatures. It is found to yield a first-order ordering transition at 288 K with small hysteresis and negligible system size effects. A detailed investigation in terms of various structural and dynamical measurements indicates that the ordered phase is of the smectic type rather than nematic, as observed experimentally. The ordering temperature can be brought close to the experimental value of 308.5 K through the simple rescaling of the intermolecular effective interaction potentials employed in the coarse-grained model. A nematic ordered phase can be obtained from the coarse-grained model by scaling up the head-head and tail-tail effective interaction potentials obtained by IBI.

AB - A coarse-grained model is derived for a liquid-crystal-forming molecule, 4-cyano-4′-pentylbiphenyl (5CB), from a detailed atomistic model using the iterative Boltzmann inversion (IBI) method in the isotropic phase at 315 K and 1 bar. The coarse-grained model consists of five "superatoms" (one for the cyano group, two for the aromatic rings in the biphenyl moiety, and two for the alkyl tail), which are categorized as three types. A modification of IBI, wherein only one of the effective intermolecular potentials (the one corresponding to the superatom pair whose intermolecular correlation function exhibits the highest deviation from the atomistic one) is updated at each iteration, proves to be necessary to achieve convergence. The coarse-grained model, which enables a savings of a factor of 35 in computational cost relative to atomistic simulation, is used to explore ordering into liquid-crystalline phases at lower temperatures. It is found to yield a first-order ordering transition at 288 K with small hysteresis and negligible system size effects. A detailed investigation in terms of various structural and dynamical measurements indicates that the ordered phase is of the smectic type rather than nematic, as observed experimentally. The ordering temperature can be brought close to the experimental value of 308.5 K through the simple rescaling of the intermolecular effective interaction potentials employed in the coarse-grained model. A nematic ordered phase can be obtained from the coarse-grained model by scaling up the head-head and tail-tail effective interaction potentials obtained by IBI.

UR - http://www.scopus.com/inward/record.url?scp=77957724835&partnerID=8YFLogxK

U2 - 10.1021/ie901957r

DO - 10.1021/ie901957r

M3 - Article

VL - 50

SP - 546

EP - 556

JO - Industrial & Engineering Chemistry Research

JF - Industrial & Engineering Chemistry Research

SN - 0888-5885

IS - 2

ER -