125 research outputs found

    Structural Properties of Two-Dimensional Polymers

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    We present structural properties of two-dimensional polymers as far as they can be described by percolation theory. The percolation threshold, critical exponents and fractal dimensions of clusters are determined by computer simulation and compared to the results of percolation theory. We also describe the dependence of the typical cluster structures on the reaction rate.Comment: 7 pages, LaTeX with RevTeX and epsf styles and PostScript figures included (uuencoded shell archive), TVP-93051

    Deformation of polymer films by bending forces

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    We study the deformation of nano--scale polymer films which are subject to external bending forces by means of computer simulation. The polymer is represented by a generalized bead--spring--model, intended to reproduce characteristic features of n--alkanes. The film is loaded by the action of a prismatic blade which is pressed into the polymer bulk from above and a pair of columns which support the film from below. The interaction between blade and support columns and the polymer is modelled by the repulsive part of a Lennard-Jones potential. For different system sizes as well as for different chainlengths, this nano--scale experiment is simulated by molecular dynamics methods. Our results allow us to give a first characterization of deformed states for such films. We resolve the kinetic and the dynamic stage of the deformation process in time and access the length scale between discrete particle and continuum mechanics behaviour. For the chainlengths considered here, we find that the deformation process is dominated by shear. We observe strangling effects for the film and deformation fluctuations in the steady state.Comment: 15 pages, 8 figure

    Monte Carlo simulations reveal the straightening up of an end-grafted flexible chain with a rigid side chain

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    We have studied the conformational properties of a flexible end-grafted chain (length NN) with a rigid side chain (length SS) by means of Monte Carlo simulations. Depending on the lengths NN and SS and the branching site, bb, we observe a considerable straightening of the flexible backbone as quantified via the gyration tensor. For b=Nb=N, i.e. when attaching the side chain to the free end of the flexible backbone, the effect was strongest

    Impact of Anomalous Diffusion on Biochemical Kinetics

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