Nematic Braids: Modeling of Colloidal Structures

Journal article

Our recent advances in modeling of colloidal superstructures in spatially confined nematic liquid crystals are briefly reviewed. The approach is phenomenological and is based on Landau-de Gennes type free energy, where the effects of confinement and external fields are also taken into account. The inter-particle couplings that result in a nematic solvent are effectively many-body interactions. The complexity of the couplings leads to numerous nematic and colloidal structures not present in simple liquidswhere van derWaalsand electrostaticinteractions are dominant.Alocal "heating" tothe isotropic phaseisperformed, followedby a fast quenchtothe nematic phase. In the relaxation process that conserves the topological charge, a number of metastable colloidal superstructures are formed. Here we focus our attention on the entangled structures where colloidal particles arecoupledbyanentangled networkof delocalized disclination lines (nematic braid): colloidal dimers, chains, and multiscale structures. The string-like coupling provided by such disclination lines is much more robust comparedtoan interaction basedon anarray oflocalized disclinations.The controlled formation ofentangled colloidal structures opens new ways tothe assemblyof colloidal photonic crystals and hierarchical structures that could lead to metamaterials. Copyright © Taylor and Francis Group, LLC.

Authors: Ravnik, M; Crnko, B; Zumer, S

• Publication status: Published
• Journal: MOLECULAR CRYSTALS AND LIQUID CRYSTALS
• Volume: 508
• Issue: 1
• Pages: 150-162
• Publication date: 2009-01-01
• DOI: 10.1080/15421400903060532
• EISSN: 1563-5287
• ISSN: 1542-1406
• Language: English
• Keywords: colloid; nematic braid; hierarchical structure; nematic liquid crystal; entanglement; disclination