Nanoparticle localization within chiral liquid crystal defect lines and nanoparticle interactions

Journal Article · Tue Mar 07 00:00:00 EST 2023 · Physical Review. E

DOI:https://doi.org/10.1103/physreve.107.034701· OSTI ID:2341905

Tasinkevych, Mykola ^[1]; Park, Sungoh ^[2]; Mundoor, Haridas ^[2]; Smalyukh, Ivan I. ^[3]

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1. Nottingham Trent University (United Kingdom); Universidade de Lisboa (Portugal); Hiroshima University, Higashihiroshima (Japan); CU-Boulder
2. University of Colorado, Boulder, CO (United States)
3. Hiroshima University, Higashihiroshima (Japan); University of Colorado, Boulder, CO (United States); National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Self-assembly of colloidal particles into predefined structures is a promising way to design inexpensive manmade materials with advanced macroscopic properties. Doping of nematic liquid crystals (LCs) with nanoparticles has a series of advantages in addressing these grand scientific and engineering challenges. It also provides a very rich soft matter platform for the discovery of unique condensed matter phases. The LC host naturally allows the realization of diverse anisotropic interparticle interactions, enriched by the spontaneous alignment of anisotropic particles due to the boundary conditions of the LC director. Here we demonstrate theoretically and experimentally that the ability of LC media to host topological defect lines can be used as a tool to probe the behavior of individual nanoparticles as well as effective interactions between them. LC defect lines irreversibly trap nanoparticles enabling controlled particle movement along the defect line with the use of a laser tweezer. Minimization of Landau–de Gennes free energy reveals a sensitivity of the ensuing effective nanoparticle interaction to the shape of the particle, surface anchoring strength, and temperature, which determine not only the strength of the interaction but also its repulsive or attractive character. Theoretical results are supported qualitatively by experimental observations. Furthermore, this work may pave the way toward designing controlled linear assemblies as well as one-dimensional crystals of nanoparticles such as gold nanorods or quantum dots with tunable interparticle spacing.

• Research Organization: University of Colorado, Boulder, CO (United States)
• Sponsoring Organization: Portuguese Foundation for Science and Technology (FCT); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• Grant/Contract Number: SC0019293
• OSTI ID: 2341905
• Alternate ID(s): OSTI ID: 1960323
• Journal Information: Physical Review. E, Journal Name: Physical Review. E Journal Issue: 3 Vol. 107; ISSN 2470-0045
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Charged colloids
Complex fluids
Liquid crystals