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Title: Spontaneous topological charging of tactoids in a living nematic

Abstract

Living nematic is a realization of an active matter combining a nematic liquid crystal with swimming bacteria. The material exhibits a remarkable tendency towards spatio-temporal self-organization manifested in formation of dynamic textures of self-propelled half-integer topological defects (disclinations). Here we report on the study of such living nematic near normal inclusions, or tactoids, naturally realized in liquid crystals close to the isotropic-nematic (I-N) phase transition. On the basis of the computational analysis, we have established that tactoid's I-Ninterface spontaneously acquire negative topological charge which is proportional to the tactoid's size and depends on the concentration of bacteria. The observed negative charging is attributed to the drastic difference in the mobilities of +1/2 and -1/2 topological defects in active systems. The effect is described in the framework of a kinetic theory for point-like weakly-interacting defects with different mobilities. Our dedicated experiment fully confirmed the theoretical prediction. Here, the results hint into new strategies for control of active matter.

Authors:
ORCiD logo [1];  [2];  [3]
  1. Northwestern Univ., Evanston, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Northwestern Univ., Evanston, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Pennsylvania State Univ., University Park, PA (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1437834
Alternate Identifier(s):
OSTI ID: 1435953
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Published Article
Journal Name:
New Journal of Physics
Additional Journal Information:
Journal Volume: 20; Journal Issue: 4; Journal ID: ISSN 1367-2630
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; living liquid crystal; active nematic; motile bacteria; tactoids; topological charge

Citation Formats

Genkin, Mikhail M., Sokolov, Andrey, and Aranson, Igor S. Spontaneous topological charging of tactoids in a living nematic. United States: N. p., 2018. Web. doi:10.1088/1367-2630/aab1a3.
Genkin, Mikhail M., Sokolov, Andrey, & Aranson, Igor S. Spontaneous topological charging of tactoids in a living nematic. United States. doi:10.1088/1367-2630/aab1a3.
Genkin, Mikhail M., Sokolov, Andrey, and Aranson, Igor S. Fri . "Spontaneous topological charging of tactoids in a living nematic". United States. doi:10.1088/1367-2630/aab1a3.
@article{osti_1437834,
title = {Spontaneous topological charging of tactoids in a living nematic},
author = {Genkin, Mikhail M. and Sokolov, Andrey and Aranson, Igor S.},
abstractNote = {Living nematic is a realization of an active matter combining a nematic liquid crystal with swimming bacteria. The material exhibits a remarkable tendency towards spatio-temporal self-organization manifested in formation of dynamic textures of self-propelled half-integer topological defects (disclinations). Here we report on the study of such living nematic near normal inclusions, or tactoids, naturally realized in liquid crystals close to the isotropic-nematic (I-N) phase transition. On the basis of the computational analysis, we have established that tactoid's I-Ninterface spontaneously acquire negative topological charge which is proportional to the tactoid's size and depends on the concentration of bacteria. The observed negative charging is attributed to the drastic difference in the mobilities of +1/2 and -1/2 topological defects in active systems. The effect is described in the framework of a kinetic theory for point-like weakly-interacting defects with different mobilities. Our dedicated experiment fully confirmed the theoretical prediction. Here, the results hint into new strategies for control of active matter.},
doi = {10.1088/1367-2630/aab1a3},
journal = {New Journal of Physics},
number = 4,
volume = 20,
place = {United States},
year = {Fri Apr 13 00:00:00 EDT 2018},
month = {Fri Apr 13 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1088/1367-2630/aab1a3

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