Ionically charged topological defects in nematic fluids

Everts, Jeffrey Christopher (author), Ravnik, Miha (author)

Charge profiles in liquid electrolytes are of crucial importance for applications such as supercapacitors, fuel cells, batteries, or the self-assembly of particles in colloidal or biological settings. However, creating localized (screened) charge profiles in the bulk of such electrolytes generally requires the presence of surfaces—for example, provided by colloidal particles or outer surfaces of the material—which poses a fundamental constraint on the material design. Here, we show that topological defects in nematic electrolytes can perform as regions for local charge separation, forming charged defect cores and, in some geometries, even electric multilayers, as opposed to the electric double layers found in isotropic electrolytes. Using a Landau-de Gennes-Poisson-Boltzmann theoretical framework, we show that ions highly effectively couple with the topological defect cores via ion solvability and with the local director-field distortions of the defects via flexoelectricity. The defect charging is shown for different defect types—lines, points, and walls—using geometries of ionically screened flat isotropic-nematic interfaces, radial hedgehog point defects, and half-integer wedge disclinations in the bulk and as stabilized by (charged) colloidal particles. More generally, our findings are relevant for possible applications where topological defects act as diffuse ionic capacitors or as ionic charge carriers.

• Language: English
• Keywords: condensed matter physics, nematic liquid crystals, topological defects, electrostatic double layer, chemical physics, materials science, soft matter, electrostatic double layer forces, flexoelectricity, charged colloids, interfaces, condensed matter, materials, applied physics, polymers
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 17 str.
• Numbering: Vol. 11, iss. 1, art. 011054
• PID: 20.500.12556/RUL-125441
• UDC: 538.9
• ISSN on article: 2160-3308
• DOI: 10.1103/PhysRevX.11.011054
• COBISS.SI-ID: 55545603
• Publication date in RUL: 17.03.2021

Record is a part of a journal

• Title: Physical review
• Shortened title: Phys. rev., X
• Publisher: American Physical Society
• ISSN: 2160-3308
• COBISS.SI-ID: 19686152

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: fizika kondenzirane snovi, nematski tekoči kristali, topološki defekti, elektrostatska dvojna plast