Effects of anchoring strength on the diffusivity of nanoparticles in model liquid-crystalline fluids

The diffusivity of a nanoparticle suspended in a liquid crystal is investigated in the limit of nematic ordering and under isotropic conditions. Molecular simulations are performed with the liquid-crystalline solvent represented at the level of Gay-Berne mesogens in the canonical (N,V,T) ensemble. The mesogen-colloid interaction strength is varied to induce anchoring that ranges from parallel to perpendicular. Mean square displacements, orientational correlation functions, and relative colloidal diffusivities are reported for different types of mesogenic anchoring on the nanoparticle. The Gay-Berne parametrization is contextualized with respect to experimental observations, and a specific set of parameters is found to reproduce the characteristic ratio of mesogenic diffusivities observed in recent experiments. The results presented in this work provide a means to determine anchoring strength at small length scales, and the parameterizations provided in this work could serve as a starting point to interpret experimental data for nanoparticle suspensions in liquid-crystals at a molecular level.