Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.

The topology and geometry of closed defect loops is studied in chiral nematic colloids with variable chirality. The colloidal particles with perpendicular surface anchoring of liquid crystalline molecules are inserted in a twisted nematic cell with the thickness that is only slightly larger than the...

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Main Authors: Jampani, V, Škarabot, M, Ravnik, M, Čopar, S, Žumer, S, Muševič, I
Format: Journal article
Language:English
Published: 2011
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author Jampani, V
Škarabot, M
Ravnik, M
Čopar, S
Žumer, S
Muševič, I
author_facet Jampani, V
Škarabot, M
Ravnik, M
Čopar, S
Žumer, S
Muševič, I
author_sort Jampani, V
collection OXFORD
description The topology and geometry of closed defect loops is studied in chiral nematic colloids with variable chirality. The colloidal particles with perpendicular surface anchoring of liquid crystalline molecules are inserted in a twisted nematic cell with the thickness that is only slightly larger than the diameter of the colloidal particle. The total twist of the chiral nematic structure in cells with parallel boundary conditions is set to 0, π, 2π, and 3π, respectively. We use the laser tweezers to discern the number and the topology of the -1/2 defect loops entangling colloidal particles. For a single colloidal particle, we observe that a single defect loop is winding around the particle, with the winding pattern being more complex in cells with higher total twist. We observe that colloidal dimers and colloidal clusters are always entangled by one or several -1/2 defect loops. For colloidal pairs in π-twisted cells, we identify at least 17 different entangled structures, some of them exhibiting linked defect loops-Hopf link. Colloidal entanglement is even richer with a higher number of colloidal particles, where we observe not only linked, but also colloidal clusters knotted into the trefoil knot. The experiments are in good agreement with numerical modeling using Landau-de Gennes theory coupled with geometrical and topological considerations using the method of tetrahedral rotation.
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spelling oxford-uuid:a9809510-487a-4e81-afc8-687f4e07bfb82022-03-27T03:08:53ZColloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a9809510-487a-4e81-afc8-687f4e07bfb8EnglishSymplectic Elements at Oxford2011Jampani, VŠkarabot, MRavnik, MČopar, SŽumer, SMuševič, IThe topology and geometry of closed defect loops is studied in chiral nematic colloids with variable chirality. The colloidal particles with perpendicular surface anchoring of liquid crystalline molecules are inserted in a twisted nematic cell with the thickness that is only slightly larger than the diameter of the colloidal particle. The total twist of the chiral nematic structure in cells with parallel boundary conditions is set to 0, π, 2π, and 3π, respectively. We use the laser tweezers to discern the number and the topology of the -1/2 defect loops entangling colloidal particles. For a single colloidal particle, we observe that a single defect loop is winding around the particle, with the winding pattern being more complex in cells with higher total twist. We observe that colloidal dimers and colloidal clusters are always entangled by one or several -1/2 defect loops. For colloidal pairs in π-twisted cells, we identify at least 17 different entangled structures, some of them exhibiting linked defect loops-Hopf link. Colloidal entanglement is even richer with a higher number of colloidal particles, where we observe not only linked, but also colloidal clusters knotted into the trefoil knot. The experiments are in good agreement with numerical modeling using Landau-de Gennes theory coupled with geometrical and topological considerations using the method of tetrahedral rotation.
spellingShingle Jampani, V
Škarabot, M
Ravnik, M
Čopar, S
Žumer, S
Muševič, I
Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title_full Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title_fullStr Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title_full_unstemmed Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title_short Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.
title_sort colloidal entanglement in highly twisted chiral nematic colloids twisted loops hopf links and trefoil knots
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