Defects around nanocolloids in nematic solvents simulated by Multi-particle Collision Dynamics

Colloids of nanometric size dispersed in a nematic environment are simulated using a hybrid algorithm that combines rules from Multi-particle Collision Dynamics and Molecular Dynamics. Coupling between flow and orientation fields is incorporated through the application of the Leslie–Ericksen theory for reorientation of slender rods under flow. It is found that Multi-particle Collision Dynamics sustains Saturn ring defects in the solvent when homeotropic anchoring on the colloids is considered. Changes on these topological structures induced by different anchoring strengths and spontaneous fluctuating flows are quantified. Stable defect structures around two close colloidal particles are observed that coincide with those obtained in experiments and alternative numerical techniques. Simulations of uniform nematic flow around the suspended colloid are conducted. It is found that Saturn rings are displaced along the stream direction. Large flows can separate the Saturn ring from the colloid, though the motion of the defect and the suspended particle reaches a steady state where disclinations are aligned with the streamlines.