6 research outputs found
Simple flexible polymers in a spherical cage
We report the results of Monte Carlo simulations investigating the effect of
a spherical confinement within a simple model for a flexible homopolymer. We
use the parallel tempering method combined with multi-histogram reweighting
analysis and multicanonical simulations to investigate thermodynamical
observables over a broad range of temperatures, which enables us to describe
the behavior of the polymer and to locate the freezing and collapse
transitions. We find a strong effect of the spherical confinement on the
location of the collapse transition, whereas the freezing transition is hardly
effected.Comment: 7 pages, 4 figure
Scaling laws for random walks in long-range correlated disordered media
We study the scaling laws of diffusion in two-dimensional media with
long-range correlated disorder through exact enumeration of random walks. The
disordered medium is modelled by percolation clusters with correlations
decaying with the distance as a power law, , generated with the
improved Fourier filtering method. To characterize this type of disorder, we
determine the percolation threshold by investigating
cluster-wrapping probabilities. At , we estimate the
(sub-diffusive) walk dimension for different correlation
exponents . Above , our results suggest a normal random walk
behavior for weak correlations, whereas anomalous diffusion cannot be ruled out
in the strongly correlated case, i.e., for small .Comment: 11 pages, 6 figure
Linear and ring polymers in confined geometries
A short overview of the theoretical and experimental works on the polymer-colloid mixtures is given. The behaviour of a dilute solution of linear and ring polymers in confined geometries like slit of two parallel walls or in the solution of mesoscopic colloidal particles of big size with different adsorbing or repelling properties in respect to polymers is discussed. Besides, we consider the massive field theory approach in fixed space dimensions d = 3 for the investigation of the interaction between long flexible polymers and mesoscopic colloidal particles of big size and for the calculation of the correspondent depletion interaction potentials and the depletion forces between confining walls. The presented results indicate the interesting and nontrivial behavior of linear and ring polymers in confined geometries and give possibility better to understand the complexity of physical effects arising from confinement and chain topology which plays a significant role in the shaping of individual chromosomes and in the process of their segregation, especially in the case of elongated bacterial cells. The possibility of using linear and ring polymers for production of new types of nano- and micro-electromechanical devices is analyzed