594 research outputs found
Generalized hydrodynamics of a dilute finite-sized particles suspension: Dynamic viscosity
We present a mesoscopic hydrodynamic description of the dynamics of colloidal
suspensions. We consider the system as a gas of Brownian particles suspended in
a Newtonian heat bath subjected to stationary non-equilibrium conditions
imposed by a velocity field. Using results already obtained in previous studies
in the field by means of a generalized Fokker-Planck equation, we obtain a set
of coupled differential equations for the local diffusion current and the
evolution of the total stress tensor. We find that the dynamic shear viscosity
of the system contains contributions arising from the finite size of the
particles.Comment: To appear in Physical Review
Self-assembly of anisotropic soft particles in two dimensions
The self assembly of core-corona discs interacting via anisotropic potentials
is investigated using Monte Carlo computer simulations. A minimal interaction
potential that incorporates anisotropy in a simple way is introduced. It
consists in a core-corona architecture in which the center of the core is
shifted with respect to the center of the corona. Anisotropy can thus be tuned
by progressively shifting the position of the core. Despite its simplicity, the
system self organize in a rich variety of structures including stripes,
triangular and rectangular lattices, and unusual plastic crystals. Our results
indicate that the amount of anisotropy does not alter the lattice spacing and
only influences the type of clustering (stripes, micells, etc.) of the
individual particles.Comment: submitte
Shape selection and mis-assembly in viral capsid formation by elastic frustration
The successful assembly of a closed protein shell (or capsid) is a key step in the replication of viruses and in the production of artificial viral cages for bio/nanotechnological applications. During self-assembly, the favorable binding energy competes with the energetic cost of the growing edge and the elastic stresses generated due to the curvature of the capsid. As a result, incomplete structures such as open caps, cylindrical or ribbon-shaped shells may emerge, preventing the successful replication of viruses. Using elasticity theory and coarse-grained simulations, we analyze the conditions required for these processes to occur and their significance for empty virus self-assembly. We find that the outcome of the assembly can be recast into a universal phase diagram showing that viruses with high mechanical resistance cannot be self-assembled directly as spherical structures. The results of our study justify the need of a maturation step and suggest promising routes to hinder viral infections by inducing mis-assembly
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