ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We consider the effects of the ratio of average bond length, l0, to excluded volume bead diameter, d0, on the dynamics of dense liquids of freely jointed bead-spring polymer chains. Monodisperse (N=50) systems for which 0.73〈l0/d0〈1.34 were simulated using molecular dynamics in the NVT ensemble at a monomer number density ρ=0.85 σ−3. The monomer friction coefficient, ζ, increased by a factor of ∼20 for a factor ∼2 increase in l0/d0. This is due to the enhancement of sphere-packing homogeneity in the melts for l0/d0〉1, which in turn increases the volume density and optimizes packing. Friction coefficients depend on local density (i.e., density of nearest neighbors around any monomer) in a manner akin to the empirical relationship between diffusivity and total number density in simple Lennard-Jones fluids [Levesque and Verlet, Phys. Rev. A 2, 2514 (1970)]. This work demonstrates the degree of interplay between structure and dynamics in macromolecular liquids. © 2002 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1445107
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