Effect of collective molecular reorientations on Brownian motion of colloids in nematic liquid crystal.

摘要: In the simplest realization of Brownian motion, a colloidal sphere moves randomly in an isotropic fluid; its mean squared displacement (MSD) grows linearly with time τ. motion orientationally ordered fluid--a nematic--is anisotropic, MSD being larger along axis molecular orientation, called director. We found that at short scales, anisotropic diffusion nematic becomes anomalous, growing slower or faster than τ; these states are respectively termed subdiffusion and superdiffusion. The anomalous occurs scales correspond to relaxation times director deformations around sphere. Once melts, normal isotropic. Our experiment shows fluctuations long-range orientational order profoundly influence diffusive regimes.