Mazza_manuscript.pdf (17.86 MB)
Emergent biaxiality in nematic microflows illuminated by a laser beam
journal contribution
posted on 2019-09-17, 12:24 authored by Jan-Christoph Eichler, Robert A Skutnik, Anupam Sengupta, Marco MazzaMarco Mazza, Martin SchoenAnisotropic fluids (e.g. liquid crystals) offer a remarkable promise as optofluidic materials owing to
the directional, tunable, and coupled interactions between the material, flow, and the optical fields.
Here we present a comprehensive in silico treatment of this anisotropic interaction by performing
nonequilibrium molecular dynamics simulations. We quantify the response of a nematic liquid crystal
(NLC) undergoing a Poiseuille flow in the Stokes regime, while being illuminated by a laser beam incident perpendicular to the flow direction. We adopt a minimalistic model to capture the interactions,
accounting for two features: first, the laser heats up the NLC locally; and second, the laser polarises
the NLC and exerts an optical torque that tends to reorient molecules of the nematic phase. Because
of this reorientation the liquid crystal exhibits small regions of biaxiality, where the nematic director
is one symmetry axis and the axis of rotation for the reorientation of the molecules is the other one.
We find that the relative strength of the viscous and the optical torques mediates the flow-induced
response of the biaxial regions, thereby tuning the emergence, shape and location of the regions of
enhanced biaxiality. The mechanistic framework presented here promises experimentally tractable
routes toward novel optofluidic applications based on material-flow-light interactions.
Funding
ATTRACT Investigator Grant of the Luxembourg National Research Fund [grant number A17/MS/11572821/MBRACE].
History
School
- Science
Department
- Mathematical Sciences
Published in
Molecular PhysicsVolume
117Issue
23-24Pages
3715-3733Publisher
Informa UK LimitedVersion
- AM (Accepted Manuscript)
Rights holder
© Taylor and FrancisPublisher statement
This is an Accepted Manuscript of an article published by Taylor & Francis in Molecular Physics on 16/09/2019 available online: https://doi.org/10.1080/00268976.2019.1663286Acceptance date
2019-08-27Publication date
2019-09-16Copyright date
2019ISSN
0026-8976eISSN
1362-3028Publisher version
Language
- en
Depositor
Dr Marco MazzaUsage metrics
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