Inhomogeneous assembly of driven nematic colloids

We present a quantitative analysis of the nonequilibrium assembly of colloidal particles dispersed ina nematic liquid crystal. The driven particles assemble into reconfigurable circular clusters by liquid-crystal-enabled electrokinetic phenomena generated by an AC electric field that provides propul...

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Bibliographic Details
Authors: Pagès Casas, Josep M., Straube, Arthur V., Tierno, Pietro, Ignés i Mullol, Jordi, Sagués i Mestre, Francesc
Format: article
Status:Versión aceptada para publicación
Publication Date:2018
Country:España
Institution:Universidad de Barcelona
Repository:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/141945
Online Access:https://hdl.handle.net/2445/141945
Access Level:Open access
Keyword:Col·loides
Cristalls líquids nemàtics
Colloids
Nematic liquid crystals
Description
Summary:We present a quantitative analysis of the nonequilibrium assembly of colloidal particles dispersed ina nematic liquid crystal. The driven particles assemble into reconfigurable circular clusters by liquid-crystal-enabled electrokinetic phenomena generated by an AC electric field that provides propulsionalong the local director. We identify the coexistence of different aggregation states, including a central,jammed core, where short-range elastic attraction dominates, surrounded by a liquid-like corona whereparticles retain their mobility but reach a mechanical equilibrium that we rationalize in terms of abalance between centripetal phoretic drive and pairwise repulsion. An analysis of the compressibleliquid-like region reveals a linear density profile that can be tuned with the field frequency, and abond-orientational order that reaches a maximum at intermediate packing densities, where elasticeffects are minimized. Since the phoretic propulsion force acts also on assembled particles, wecompute the mechanical pressure and show that a hard-disk equation of state can be used to describethe assembly of this driven system.