Monte Carlo simulation of many-arm star polymers in two-dimensional good solvents in the bulk and at a surface
A Monte Carlo technique is proposed for the simulation of statistical properties of many-arm star polymers on lattices. In this vectorizing algorithm, the length of each arml is increased by one, step by step, from a starting configuration withl=1 orl=2 which is generated directly. This procedure is carried out for a large sample (e.g., 100,000 configurations). As an application, we have studied self-avoiding stars on the square lattice with arm lengths up tol max=125 and up tof=20 arms, both in the bulk and in the geometry where the center of the star is adsorbed on a repulsive surface. The total number of configurations, which behaves asN∼l γ G–1μ fl , whereμ=2.6386 is the usual effective…
Scaling theory of star polymers and general polymer networks in bulk and semi-infinite good solvents
Theorie d'echelle utilisant l'equivalence entre la fonction generatrice du nombre total de configuration et la fonction de correlation a plusieurs spins du modele de Heisenberg classique a n composantes dans la limite n→0
Insertion of Be Atoms inC60Fullerene Cages:Be@C60
Radioactive endohedral {sup 7}Be@C{sub 60} can be detected using radiochemical and radiochromatographic techniques in the final solvent. Such a {sup 7}Be atom can penetrate into the C{sub 60} cage to produce {sup 7}Be@C{sub 60} by a recoil process of the nuclear reactions. An {ital ab} {ital initio} molecular dynamics simulation was carried out to demonstrate that a direct insertion process is really possible. Both the experimental and the theoretical results were consistent with each other. {copyright} {ital 1996 The American Physical Society.}
Dynamics of star polymers in a good solvent: A Kramers potential treatment
The ‘‘effective’’ relaxation time τ of isolated star polymers with excluded volume interactions in the Rouse model limit (i.e., disregarding hydrodynamic interactions present in real solvents) is studied varying both the number of arms f and the number of monomers per arm l. Here τ is defined from the response of the gyration radius of the star polymer to a Kramers potential that describes the effect of shear flow in lowest order in the shear rate. Monte Carlo simulations are performed with two different techniques (simple sampling with enrichment or dynamic Monte Carlo, respectively) for two different models (simple self‐avoiding walks with an extended core or the bond fluctuation model, r…
Scaling theory for radial distributions of star polymers in dilute solution in the bulk and at a surface, and scaling of polymer networks near the adsorption transition
Monomer density profiles ρ(r) and center–end distribution functions g(rCE) of star polymers are analyzed by using a scaling theory in arbitrary dimensions d, considering dilute solutions and the good solvent limit. Both the case of a free star in the bulk and of a center‐adsorbed star at a free surface are considered. In the latter case of a semi‐infinite problem, a distinction is made between repulsive walls, attractive walls—where for large arm length l the configuration of the star is quasi‐(d−1) dimensional—, and ‘‘marginal walls’’ where for l→∞ the transition from d‐dimensional structure occurs. For free stars, ρ(r) behaves as r−d+1/ν for small r, where ν is the exponent describing the…