Static Rouse Modes and Related Quantities: Corrections to Chain Ideality in Polymer Melts (2007)
Meyer, H., Wittmer, J. P., Kreer, T., Beckrich, P., Johner, A., Farago, J., ...
Following the Flory ideality hypothesis intrachain and interchain excluded volume interactions are supposed to compensate each other in dense polymer systems. Multi-chain effects should thus be...
Wittmer, J. P., Beckrich, P., Meyer, H., Cavallo, A., Johner, A., Baschnagel, J.
Presenting theoretical arguments and numerical results we demonstrate long-range intrachain correlations in concentrated solutions and melts of long flexible polymers which cause a systematic...
Dynamic Glass Transition in Two Dimensions (2007)
Bayer, M., Brader, J., Ebert, F., Lange, E., Fuchs, M., Maret, G., ...
The question about the existence of a structural glass transition in two dimensions is studied using mode coupling theory (MCT). We determine the explicit d-dependence of the memory functional of...
Beckrich, P., Johner, A., Semenov, A. N., Obukhov, S. P., Benoit, H., Wittmer, J. P.
We discuss theoretically and numerically the intramolecular form factor $F(q)$ in dense polymer systems. Following Flory's ideality hypothesis, chains in the melt adopt Gaussian configurations and...
Dynamic Glass Transition in Two Dimensions (2007)
Bayer, M., Brader, J.M., Ebert, F., Fuchs, M., Lange, E., Maret, G., ...
Why polymer chains in a melt are not random walks (2006)
Wittmer, J. P., Beckrich, P., Johner, J., Semenov, A. N., Obukhov, S. P., Meyer, H., ...
A cornerstone of modern polymer physics is the `Flory ideality hypothesis' which states that a chain in a polymer melt adopts `ideal' random-walk-like conformations. Here we revisit theoretically and...
Are polymer melts "ideal"? (2006)
Wittmer, J. P., Beckrich, P., Crevel, F., Huang, C. C., Cavallo, A., Kreer, T., ...
It is commonly accepted that in concentrated solutions or melts high-molecular weight polymers display random-walk conformational properties without long-range correlations between subsequent bonds....
On the Dynamics and Disentanglement in Thin and Two-Dimensional Polymer Films (2006)
Meyer, H., Kreer, T., Cavallo, A., Wittmer, J. P., Baschnagel, J.
We present results from molecular dynamics simulations of strictly two-dimensional (2D) polymer melts and thin polymer films in a slit geometry of thickness of the order of the radius of gyration. We...
Cavallo, A., Müller, M., Wittmer, J. P., Johner, A., Binder, K.
Conformational properties of polymer melts confined between two hard structureless walls are investigated by Monte Carlo simulation of the bond-fluctuation model. Parallel and perpendicular...
On the Dynamics and Disentanglement in Thin and Two-Dimensional Polymer Films (2006)
Meyer, H., Kreer, T., Cavallo, A., Wittmer, J. P., Baschnagel, J.
We present results from molecular dynamics simulations of strictly two-dimensional (2D) polymer melts and thin polymer films in a slit geometry of thickness of the order of the radius of gyration. We...
Monte Carlo SImulation of Polymers: Coarse-Grained Models (2006)
Baschnagel, J., Wittmer, J. P., Meyer, H.
A coarse-grained simulation model eliminates microscopic degrees of freedom and represents a polymer by a simplified structure. A priori, two classes of coarse-grained models may be distinguished:...
On the Dynamics and Disentanglement in Thin and Two-Dimensional Polymer Films (2006)
Meyer, H., Kreer, T., Cavallo, A., Wittmer, J. P., Baschnagel, J.
We present results from molecular dynamics simulations of strictly two-dimensional (2D) polymer melts and thin polymer films in a slit geometry of thickness of the order of the radius of gyration. We...
On the Dynamics and Disentanglement in Thin and Two-Dimensional Polymer Films (2006)
Meyer, H., Kreer, T., Cavallo, A., Wittmer, J. P., Baschnagel, J.
We present results from molecular dynamics simulations of strictly two-dimensional (2D) polymer melts and thin polymer films in a slit geometry of thickness of the order of the radius of gyration. We...
Long Range Bond-Bond Correlations in Dense Polymer Solutions (2005)
Wittmer, J. P., Meyer, H., Baschnagel, J., Johner, A., Obukhov, S., Mattioni, L., ...
The scaling of the bond-bond correlation function $C(s)$ along linear polymer chains is investigated with respect to the curvilinear distance, $s$, along the flexible chain and the monomer density,...
Continuum limit of amorphous elastic bodies (III): Three dimensional systems (2005)
Léonforte, F., Boissière, R., Tanguy, A., Wittmer, J.P.
Extending recent numerical studies on two dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three dimensional (weakly polydisperse) Lennard-Jones systems. While...
Continuum limit of amorphous elastic bodies (II): Response to a point source (2005)
Leonforte, F., Tanguy, A., Wittmer, J.P.
The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress...
Continuum limit of amorphous elastic bodies (III): Three dimensional systems (2005)
Léonforte, F., Boissière, R., Tanguy, A., Wittmer, J. P.
Extending recent numerical studies on two dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three dimensional (weakly polydisperse) Lennard-Jones systems. While...
Continuum limit of amorphous elastic bodies (II): Response to a point source (2005)
Leonforte, F., Tanguy, A., Wittmer, J.P.
The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress...
Continuum limit of amorphous elastic bodies (III): Three dimensional systems (2005)
Léonforte, F., Boissière, R., Tanguy, A., Wittmer, J.P.
Extending recent numerical studies on two dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three dimensional (weakly polydisperse) Lennard-Jones systems. While...
Continuum limit of amorphous elastic bodies (III): Three dimensional systems (2005)
Léonforte, F., Boissière, R., Tanguy, A., Wittmer, J.P.
Extending recent numerical studies on two dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three dimensional (weakly polydisperse) Lennard-Jones systems. While...
Continuum limit of amorphous elastic bodies (III): Three dimensional systems (2005)
Léonforte, F., Boissière, R., Tanguy, A., Wittmer, J.P.
Extending recent numerical studies on two dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three dimensional (weakly polydisperse) Lennard-Jones systems. While...
Cavallo, A., Müller, M., Wittmer, J. P., Johner, A., Binder, K.
Conformational properties of polymer melts confined between two hard structureless walls are investigated by Monte Carlo simulation of the bond-fluctuation model. Parallel and perpendicular...
Cavallo, A., Müller, M., Wittmer, J. P., Johner, A., Binder, K.
Conformational properties of polymer melts confined between two hard structureless walls are investigated by Monte Carlo simulation of the bond-fluctuation model. Parallel and perpendicular...
Cavallo, A., Müller, M., Wittmer, J. P., Johner, A., Binder, K.
Conformational properties of polymer melts confined between two hard structureless walls are investigated by Monte Carlo simulation of the bond-fluctuation model. Parallel and perpendicular...
Monte Carlo SImulation of Polymers: Coarse-Grained Models (2004)
Baschnagel, J., Wittmer, J. P., Meyer, H.
A coarse-grained simulation model eliminates microscopic degrees of freedom and represents a polymer by a simplified structure. A priori, two classes of coarse-grained models may be distinguished:...
Long Range Bond-Bond Correlations in Dense Polymer Solutions (2004)
Wittmer, J. P., Meyer, H., Baschnagel, J., Johner, A., Obukhov, S., Mattioni, L., ...
The scaling of the bond-bond correlation function $C(s)$ along linear polymer chains is investigated with respect to the curvilinear distance, $s$, along the flexible chain and the monomer density,...
Monte Carlo SImulation of Polymers: Coarse-Grained Models (2004)
Baschnagel, J., Wittmer, J. P., Meyer, H.
A coarse-grained simulation model eliminates microscopic degrees of freedom and represents a polymer by a simplified structure. A priori, two classes of coarse-grained models may be distinguished:...
Long Range Bond-Bond Correlations in Dense Polymer Solutions (2004)
Wittmer, J. P., Meyer, H., Baschnagel, J., Johner, A., Obukhov, S., Mattioni, L., ...
The scaling of the bond-bond correlation function $C(s)$ along linear polymer chains is investigated with respect to the curvilinear distance, $s$, along the flexible chain and the monomer density,...
Continuum limit of amorphous elastic bodies (II): Response to a point source (2004)
Leonforte, F., Tanguy, A., Wittmer, J.P.
The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress...
Monte Carlo SImulation of Polymers: Coarse-Grained Models (2004)
Baschnagel, J., Wittmer, J. P., Meyer, H.
A coarse-grained simulation model eliminates microscopic degrees of freedom and represents a polymer by a simplified structure. A priori, two classes of coarse-grained models may be distinguished:...
Long Range Bond-Bond Correlations in Dense Polymer Solutions (2004)
Wittmer, J. P., Meyer, H., Baschnagel, J., Johner, A., Obukhov, S., Mattioni, L., ...
The scaling of the bond-bond correlation function $C(s)$ along linear polymer chains is investigated with respect to the curvilinear distance, $s$, along the flexible chain and the monomer density,...
Continuum limit of amorphous elastic bodies (II): Response to a point source (2004)
Leonforte, F., Tanguy, A., Wittmer, J.P.
The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress...
Continuum limit of amorphous elastic bodies (II): Response to a point source (2003)
Leonforte, F., Tanguy, A., Wittmer, J. P.
The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress...
Mattioni,L., Wittmer,J. P., Baschnagel,J., Barrat,J. L., Luijten,E.
Correlations in the motion of reptating polymers in a melt are investigated by means of Monte Carlo simulations of the three-dimensional slithering-snake version of the bond-fluctuation model....
Mattioni, L., Wittmer, J. P., Baschnagel, J., Barrat, J. L., Luijten, E.
Correlations in the motion of reptating polymers in a melt are investigated by means of Monte Carlo simulations of the three-dimensional slithering-snake version of the bond-fluctuation model....
Mattioni, L., Wittmer, J. P., Baschnagel, J., Luijten, E.
The correlations in the motion of reptating polymers in their melt are investigated by means of kinetic Monte Carlo simulations of the three dimensional slithering snake version of the...
Tanguy, A., Wittmer, J. P., Leonforte, F.
The approach of the elastic continuum limit in small amorphous bodies formed by weakly polydisperse Lennard-Jones beads is investigated in a systematic finite-size study. We show that classical...
Vibrations of amorphous, nanometric structures: When does continuum theory apply? (2001)
Wittmer, J. P., Tanguy, A., Lewis, L.
Structures involving solid particles of nanometric dimensions play an increasingly important role in material sciences. These structures are often characterized through the vibrational properties of...
Milchev, A., Wittmer, J. P., Landau, D.
The osmotic pressure $P$ in equilibrium polymers (EP) in good solvent is investigated by means of a three dimensional off-lattice Monte Carlo simulation. Our results compare well with real space...
The interplay of topological constraints, excluded volume interactions, persistence length and dynamical entanglement length in solutions and melts of linear chains and ring polymers is investigated...
Dynamical Monte Carlo Study of Equilibrium Polymers (II): The Role of Rings (2000)
We investigate by means of a number of different dynamical Monte Carlo simulation methods the self-assembly of equilibrium polymers in dilute, semidilute and concentrated solutions under good-solvent...
Formation and Equilibrium Properties of Living Polymer Brushes (1999)
Milchev, A., Wittmer, J. P., Landau, D. P.
Polydisperse brushes obtained by reversible radical chain polymerization reaction onto a solid substrate with surface-attached initiators, are studied by means of an off-lattice Monte Carlo algorithm...
Milchev, A., Wittmer, J. P., Landau, D. P.
An off-lattice Monte Carlo algorithm for solutions of equilibrium polymers (EP) is proposed. At low and moderate densities this is shown to reproduce faithfully the (static) properties found recently...
Topological effects in ring polymers (II): Influence of persistence length (1999)
Muller, M., Wittmer, J. P., Cates, M. E.
The interplay of topological constraints and persistence length of ring polymers in their own melt is investigated by means of dynamical Monte Carlo simulations of a three dimensional lattice model....
A Monte Carlo Study of Equilibrium Polymers in a Shear Flow (1999)
Milchev, A., Wittmer, J. P., Landau, D. P.
We use an off-lattice microscopic model for solutions of equilibrium polymers (EP) in a lamellar shear flow generated by means of a self-consistent external field between parallel hard walls. The...
Stresses in silos: Comparison between theoretical models and new experiments (1999)
Vanel, L., Claudin, Ph., Bouchaud, J. -Ph., Cates, M. E., Clément, E., Wittmer, J. P.
We present precise and reproducible mean pressure measurements at the bottom of a cylindrical granular column. If a constant overload is added, the pressure is linear in overload and nonmonotonic in...
Jamming and Stress Propagation in Granular Materials (1999)
Cates, M. E., Wittmer, J. P., Claudin, P.
We have recently developed some simple continuum models of static granular media which display "fragile" behaviour: they predict that the medium is unable to support certain types of infinitesimal...
Linear Aggregation Revisited: Rods, Rings and Worms (1998)
The problem of ring formation in solutions of cylindrical micelles is reinvestigated theoretically, taking into account a finite bending rigidity of the self-assembled linear objects. Transitions...
Jamming and Stress Propagation in Particulate Matter (1998)
Cates, M. E., Wittmer, J. P., Claudin, P.
We present simple models of particulate materials whose mechanical integrity arises from a jamming process. We argue that such media are generically "fragile", that is, they are unable to support...
Stress Propagation in Sand (1998)
We describe a new continuum approach to the modelling of stress propagation in static granular media, focussing on the conical sandpile created from a point source. We argue that the stress...
Topological effects in ring polymers: A computer simulation study (1998)
Mueller, M., Wittmer, J. P., Cates, M. E.
Unconcatenated, unknotted polymer rings in the melt are subject to strong interactions with neighboring chains due to the presence of topological constraints. We study this by computer simulation...
Diffusive growth of a polymer layer by in sity polymerization (1998)
Wittmer, J. P., Cates, M. E., Johner, A., Turner, M. S.
We consider the growth of a polymer layer on a flat surface in a good solvent by in-situ polymerization. This is viewed as a modified form of diffusion-limited aggregation without branching. We...
Formation of polymer brushes (1998)
In systems such as block copolymer mesophases or physical gels formed by associating copolymers, the dynamical properties are often controlled by the extraction/association of a sticking group. We...
Computational confirmation of scaling predictions for equilibrium polymers (1998)
Wittmer, J. P., Milchev, A., Cates, M. E.
We report the results of extensive Dynamic Monte Carlo simulations of systems of self-assembled Equilibrium Polymers without rings in good solvent. Confirming recent theoretical predictions, the...
Dynamical Monte Carlo Study of Equilibrium Polymers : Static Properties (1998)
Wittmer, J. P., Milchev, A., Cates, M. E.
We report results of extensive Dynamical Monte Carlo investigations on self-assembled Equilibrium Polymers (EP) without loops in good solvent. (This is thought to provide a good model of giant...
Models of stress propagation in granular media (1997)
Claudin, P., Cates, M. E., Wittmer, J. P.
Stress patterns in static granular media exhibit unusual features when compared to either liquids or elastic solids. Qualitatively, we attribute these features to the presence of `stress paths',...
Models of stress fluctuations in granular media (1997)
Claudin, P., Cates, M. E., Wittmer, J. P.
We investigate in detail two models describing how stresses propagate and fluctuate in granular media. The first one is a scalar model where only the vertical component of the stress tensor is...
Stress Propagation and Arching in Static Sandpiles (1996)
Wittmer, J. P., Cates, M. E., Claudin, P.
We present a new approach to the modelling of stress propagation in static granular media, focussing on the conical sandpile constructed from a point source. We view the medium as consisting of...