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Lock-Key Microfluidics: Simulating Nematic Colloid Advection along Wavy-Walled Channels

2024/04/10 by Karolina Wamsler, Wamsler, Karolina, Louise C. Head +3
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Liquid Crystal Research Advancements #Micro and Nano Robotics #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft)

paper · pdf · doi:10.48550/arxiv.2404.07367

openalex publication_date 2024/04/10 · openalex created_date 2024/04/13 · openalex updated_date 2026/07/30

Abstract

Liquid crystalline media mediate interactions between suspended particles and confining geometries, which not only has potential to guide patterning and bottom-up colloidal assembly, but can also control colloidal migration in microfluidic devices. However, simulating such dynamics is challenging because nemato-elasticity, diffusivity and hydrodynamic interactions must all be accounted for within complex boundaries. We model the advection of colloids dispersed in flowing and fluctuating nematic fluids confined within 2D wavy channels. A lock-key mechanism between colloids and troughs is found to be stronger for planar anchoring compared to homeotropic anchoring due to the relative location of the colloid-associated defects. Sufficiently large amplitudes result in stick-slip trajectories and even permanent locking of colloids in place. These results demonstrate that wavy walls not only have potential to direct colloids to specific docking sites but also to control site-specific resting duration and intermittent elution.

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