Collective Diffusion of Colloidal Hard Rods in Smectic Liquid Crystals: Effect of Particle Anisotropy
arXiv:1004.2897 · doi:10.1063/1.3432864
Abstract
We study the layer-to-layer diffusion in smectic-A liquid crystals of colloidal hard rods with different length-to-diameter ratios using computer simulations. The layered arrangement of the smectic phase yields a hopping-type diffusion due to the presence of permanent barriers and transient cages. Remarkably, we detect stringlike clusters composed of inter-layer rods moving cooperatively along the nematic director. Furthermore, we find that the structural relaxation in equilibrium smectic phases shows interesting similarities with that of out-of-equilibrium supercooled liquids, although there the particles are kinetically trapped in transient rather than permanent cages. Additionally, at fixed packing fraction we find that the barrier height increases with increasing particle anisotropy, and hence the dynamics is more heterogeneous and non-Gaussian for longer rods, yielding a lower diffusion coefficient along the nematic director and smaller clusters of inter-layer particles that move less cooperatively. At fixed barrier height, the dynamics becomes more non-Gaussian and heterogeneous for longer rods that move more collectively giving rise to a higher diffusion coefficient along the nematic director.
24 pages, 10 figures
References in corpus (19)
- Dynamical heterogeneities in a supercooled Lennard-Jones liquid
- String-like Clusters and Cooperative Motion in a Model Glass-Forming Liquid
- Direct experimental evidence of a growing length scale accompanying the glass transition
- Universal nature of particle displacements close to glass and jamming transitions
- Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition
- The Monte-Carlo dynamics of a binary Lennard-Jones glass-forming mixture
- Colloidal glass transition observed in confinement
- Isotropic-nematic phase transition in suspensions of filamentous virus and the neutral polymer Dextran
- Connection between Adam-Gibbs Theory and Spatially Heterogeneous Dynamics
- Enhanced stability of layered phases in parallel hard-spherocylinders due to the addition of hard spheres
- Self-diffusion of Rod-like Viruses Through Smectic Layer
- Diffusion and Relaxation Dynamics in Cluster Crystals
- Surface freezing and a two-step pathway of the isotropic-smectic phase transition in colloidal rods
- Glassy dynamics in monodisperse hard ellipsoids
- Dynamical Heterogeneities and Cooperative Motion in Smectic Liquid Crystals
- Self diffusion of particles in complex fluids: temporary cages and permanent barriers
- Dynamical Heterogeneity in Lattice Glass Models
- Non-Gaussian Dynamics in Smectic Liquid Crystals of Parallel Hard Rods
- Stability of smectic phases in hard-rod mixtures
Cited by in corpus (10)
- Classical dynamical density functional theory: from fundamentals to applications
- Fast Diffusion of Long Guest Rods in a Lamellar Phase of Short Host Particles
- Monte Carlo simulation of binary mixtures of hard colloidal cuboids
- Speeding up dynamics by tuning the non-commensurate size of rod-like particles in a smectic phase
- Heterogeneous Dynamics in Columnar Liquid Crystals of Parallel Hard Rods
- Dynamics of Hard Colloidal Cuboids in Nematic Liquid Crystals
- Brownian dynamics simulations of oblate and prolate colloidal particles in nematic liquid crystals
- Dynamics in binary cluster crystals
- Long-time relaxation dynamics in nematic and smectic liquid crystals of soft-repulsive colloidal rods
- Elastic response of colloidal smectics: insights from microscopic theory