Defect-influenced particle advection in highly confined liquid crystal flows

Area of Science:

• Soft Matter Physics
• Fluid Dynamics
• Colloidal Science

Background:

• Colloidal particles in liquid crystals exhibit complex behaviors due to anisotropic interactions.
• Understanding particle dynamics is crucial for applications in display technologies and microfluidics.

Purpose of the Study:

• To investigate the morphology of Saturn ring defects around a colloidal particle in a nematic host phase.
• To analyze the influence of defect structure and director profile on particle advection within a rectangular duct.
• To compare particle behavior in a nematic host with that in a Newtonian fluid.

Main Methods:

• Simulating the flow of a nematic host phase through a rectangular duct containing a colloidal particle.
• Analyzing the Saturn ring defect and director structure.
• Calculating the differential velocity (retardation ratio) of the particle and fluid.

Main Results:

• Observed changes in defect structures and director profiles due to particle-fluid interactions.
• Demonstrated that these changes significantly influence particle advection behavior.
• Revealed a non-monotonous dependence of the retardation ratio on the Ericksen number.

Conclusions:

• The morphology of Saturn ring defects and director structure critically affects colloidal particle movement in nematic fluids.
• Particle advection in nematic hosts differs significantly from Newtonian fluids, exhibiting complex flow dependencies.
• The Ericksen number is a key parameter governing particle-fluid differential velocity in this system.