Nucleation of a liquid crystal

Presentation (2004)

Self-poisoning of crystal nuclei in hard-rod liquids

in Journal of Physics : Condensed Matter (2004), 16(19), 2029-2036

We report a Monte Carlo study of the pathway for crystal nucleation in a fluid of hard, colloidal rods. In the earliest stages of nucleation, a lamellar crystallite forms. Subsequent thickening of this ... [more ▼]

We report a Monte Carlo study of the pathway for crystal nucleation in a fluid of hard, colloidal rods. In the earliest stages of nucleation, a lamellar crystallite forms. Subsequent thickening of this lamella is hampered by the fact that the top and bottom surfaces of this crystallite are preferentially covered by rods that align parallel to the surface. As a consequence, subsequent growth of individual crystals is stunted. Experimental evidence for such stunted crystal growth has recently been reported by Maeda and Maeda in experiments on suspensions of colloidal rods [Phys. Rev. Lett. 90, 018303 (2003)]. The simulations suggest that, in experiments, the growth of multilayer colloidal crystals can be selectively enhanced by the application of an external aligning field. [less ▲]

Self-poisoning in suspensions of anisotropic colloids

Scientific Conference (2003, August 28)

Smectic Filaments in colloidal in colloidal suspensions of rods

Presentation (2003)

Smectic Filaments in colloidal in colloidal suspensions of rods

Scientific Conference (2003)

Smectic filaments in colloidal suspensions of rods

in Physical Review. E ,Statistical, Nonlinear, and Soft Matter Physics (2002), 66(4),

In supersaturated isotropic mixtures of hard rods, smectic filaments have recently been observed. We propose a model for formation and growth of these filaments similar to the Hoffman-Lauritzen model for ... [more ▼]

In supersaturated isotropic mixtures of hard rods, smectic filaments have recently been observed. We propose a model for formation and growth of these filaments similar to the Hoffman-Lauritzen model for polymer crystallization. Filament thickness is determined by a compromise between maximizing the amount of smectic phase formed and minimizing the nucleation barrier for adding new segments to the growing filament. We compare our analytical results to kinetic Monte Carlo simulations. [less ▲]

Dynamics of the swollen lamellar phase

Scientific Conference (2001)

Dynamics of the swollen lamellar phase

in European Physical Journal E. Soft Matter (2001), 4(1), 103-114

We investigate the dynamical behavior of lamellar phases in ternary amphiphilic systems of water, oil and amphiphile. The interaction between the amphiphilic monolayers is described by the steric ... [more ▼]

We investigate the dynamical behavior of lamellar phases in ternary amphiphilic systems of water, oil and amphiphile. The interaction between the amphiphilic monolayers is described by the steric interaction due to thermal fluctuations for uncharged, and by electrostatic interactions for charged systems. The dynamics of the system is determined by the hydrodynamics of the fluid layers. The basic parameters of our model are the viscosities of the two solvents, the average thicknesses of the oil and water layers, and the bending rigidity. The model allows to consider different monolayer interactions across the oil and water layers. Relaxation rates are calculated for arbitrary wave vectors parallel and perpendicular to the average monolayer plane. We find that there is a quite complex crossover behavior from a q2 law for small parallel wave vectors to a q3 law for large q . We discuss the relevance of our result for the interpretation of dynamic light-scattering and neutron-spin-echo experiments for these systems. [less ▲]

Superheavy nuclei in selfconsistent nuclear calculations

in Physical Review. C, Nuclear Physics (1997), 56(1), 238-243

The shell structure of superheavy nuclei is investigated within various parametrizations of relativistic and nonrelativistic nuclear mean-field models. The heaviest known even-even nucleus 156 264Hs108 is ... [more ▼]

The shell structure of superheavy nuclei is investigated within various parametrizations of relativistic and nonrelativistic nuclear mean-field models. The heaviest known even-even nucleus 156 264Hs108 is used as a benchmark to estimate the predictive value of the models. From that starting point, doubly magic spherical nuclei are searched in the region Z51102140 and N5134–298. They are found at (Z5114 , N5184), (Z5120 , N5172), or at (Z5126 , N5184), depending on the parametrization. [less ▲]

Approximate spectral functions in thermal field theory

in Physical Review. D, Particles and Fields (1996), 54(5239), 1-5

Causality requires that the ~anti!commutator of two interacting field operators vanishes for spacelike coordinate differences. This implies that the Fourier transform of the spectral function of this ... [more ▼]

Causality requires that the ~anti!commutator of two interacting field operators vanishes for spacelike coordinate differences. This implies that the Fourier transform of the spectral function of this quantum field should vanish in the spacelike domain. We find that this requirement imposes some constraints on the use of resummed propagators in high temperature gauge theory. [less ▲]