Search results for "Gyration tensor"
showing 5 items of 5 documents
Homopolymer adsorption on periodically structured surfaces in systems with incommensurable lengths
2013
Surface-induced selective adsorption of homopolymers on a generic level is numerically analyzed for freely jointed chains (with a fixed bond length) whose monomers are attracted by the sites of regular periodic patterns. In particular, the behavior of the specific heat, the gyration tensor, and the bond order tensor are investigated as functions of the temperature. The properties of the transition are related to the interplay of the characteristic lengths. The adsorption proceeds in two steps for certain incommensurabilities of the bond length and the lattice constant. The corresponding adsorption mechanisms are elucidated by looking at the evolution of the inter bond angle distribution upo…
A soft-quadrumer model for diblock copolymers
2010
We present a new soft-particle type model for diblock copolymers and compare its phase diagram to experimental data as well as to results of other models. To determine the phase diagram we suggest studying geometrical characteristics of the mesophases. Diblock copolymer mesophases differ by the number and geometrical form of clusters of the two components formed in the mesophase. The form of these clusters can be characterized by values of the principle components of their gyration tensor and shape invariants determined from them. Alternatively, it has been suggested to use Minkowski functionals to characterize the global morphology of the different mesophases. We will also discuss the prac…
Monte Carlo simulation of micelle formation in block copolymer solutions
1998
Short block copolymers in selective solvents (bad for A-block, good for B-block) are modeled by flexible bead-spring chains, where beads interact with short range Morse potentials of variable strength. It is shown that already very short chains (N A = N B = 2) exhibit a rather well-defined critical micelle concentration (cmc). The mass distribution of the micelles and their gyration tensor components as well as their internal structure are studied. It is shown that the relaxation time increases exponentially with the strength E AA of the attractive energy between the A-monomers, and thus frozen-in micelles of medium size are obtained when E AA is chosen too large. Our results are compared t…
Polymer Films in the Normal-Liquid and Supercooled State: A Review of Recent Monte Carlo Simulation Results
2000
This paper reviews recent Monte Carlo simulation studies of the glassy behavior in thin polymer films. The simulations employ a version of the bond-fluctuation lattice model, in which the glass transition is driven by the competition between a stiffening of the polymers and their dense packing in the melt. The melt is geometrically confined between two impenetrable walls separated by distances ranging from once to about fifteen times the bulk radius of gyration. The confinement influences static and dynamic properties of the films: Chains close to the wall preferentially orient parallel to it. This orientation tendency propagates through the film and leads to a layer structure at low temper…
Pattern-recognising Polymer Adsorption on Structured Surfaces: Gaussian Polymers vs. Freely Jointed Chains
2014
Abstract Selective adsorption of homopolymers is exploited as a model for pattern recognition. To this end the strong adsorption regime of Gaussian polymers adsorbed on a regularly structured surface is investigated for square and triangular lattices within a discrete Edwards model. The equilibrium behaviour of the specific heat, the gyration tensor and the (nematic) bond order tensor are analysed and compared to the properties for adsorbed freely jointed polymer chains.