Nonmechanical principle for producing a flow in a homogeneously aligned microfluidic nematic channel

Izabela S̀liwa; A. V. Zakharov

doi:10.1140/epje/i2020-11953-0

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2024 Impact factor 2.2

Soft Matter and Biological Physics

Eur. Phys. J. E (2020) 43: 29
https://doi.org/10.1140/epje/i2020-11953-0

Regular Article

Nonmechanical principle for producing a flow in a homogeneously aligned microfluidic nematic channel

Izabela S̀liwa¹^* and A. V. Zakharov²^*

¹ Poznan University of Economics and Business, Al. Niepodleglosci 10, 61-875, Poznan, Poland
² Saint Petersburg Institute for Machine Sciences, The Russian Academy of Sciences, 199178, Saint Petersburg, Russia

^* e-mail: izabela.sliwa@ue.poznan.pl
^** e-mail: alexandre.zakharov@yahoo.ca

Received: 18 December 2019
Accepted: 28 April 2020
Published online: 27 May 2020

Abstract

Nonmechanical fluid pumping principle has been developed utilizing the interactions of both the director $\hat{\mathbf{n}}$ and velocity v fields and temperature T redistribution across a two-dimensional homogeneously-aligned nematic (HAN) microfluidic channel under the influence both of a heat flux $\mathbf{q}$ and the surface electric field E₀, originating from the surface charge density $\sigma$ . The heat flux $\mathbf{q}$ is caused by the laser beam pulse focused on the channel’s boundary, whereas the normally directed electric field is due to electric double layers, that is naturally created within the liquid crystal near a charged surface. Calculations, based upon the nonlinear extension of the classical Ericksen-Leslie theory, with accounting the entropy balance equation, show that due to the coupling between the $\nabla T$ and $\nabla\hat{\mathbf{n}}$ , in the HAN microfluidic channel the vortical flow $\mathbf{v}$ may be excited. The direction and magnitude of $\mathbf{v}$ is influenced by $\mathbf{q}$ and E₀, as well as by the thickness of the HAN microfluidic channel.