Non-Gaussian Dynamics in Smectic Liquid Crystals of Parallel Hard Rods

Abstract

Using computer simulations, we studied the diffusion and structural relaxation in equilibrium smectic liquid crystal bulk phases of parallel hard spherocylinders. These systems exhibit a non-Gaussian layer-to-layer diffusion due to the presence of periodic barriers and transient cages, and show remarkable similarities with the behavior of out-of-equilibrium supercooled liquids. We detect a very slow inter-layer relaxation dynamics over the whole density range of the stable smectic phase which spans a time interval of four time decades. The intrinsic nature of the layered structure yields a hopping-type diffusion which becomes more heterogeneous for higher packing fractions. In contrast, the in-layer dynamics is typical of a dense fluid with a relatively fast decay. Our results on the dynamic behavior agree well with that observed in systems of freely rotating hard rods, but differ quantitavely, as the height of the periodic barriers reduces to zero at the nematic-smectic transition for aligned rods, while it remains finite for freely rotating rods.

15 pages, 7 figures

References in corpus (11)

• Direct experimental evidence of a growing length scale accompanying the glass transition
• Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition
• Self-diffusion of Rod-like Viruses Through Smectic Layer
• Diffusion and Relaxation Dynamics in Cluster Crystals
• Dynamic light scattering measurements in the activated regime of dense colloidal hard spheres
• Dynamical Heterogeneities and Cooperative Motion in Smectic Liquid Crystals
• Self diffusion of particles in complex fluids: temporary cages and permanent barriers
• Static and dynamic heterogeneities in a model for irreversible gelation
• Molecular dynamics of a short range ordered smectic phase nanoconfined into porous silicon
• Relation between static short-range order and dynamic heterogeneities in a nanoconfined liquid crystal
• Dynamical heterogeneity in a model for permanent gels: Different behavior of dynamical susceptibilities

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• Long-time relaxation dynamics in nematic and smectic liquid crystals of soft-repulsive colloidal rods