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Monte Carlo simulation of polymeric materials: Recent progress
Author(s) -
Binder K.
Publication year - 1993
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19930690123
Subject(s) - monte carlo method , spinodal , spinodal decomposition , statistical physics , thermodynamics , ising model , mesophase , crossover , copolymer , polymer , phase (matter) , materials science , physics , mathematics , quantum mechanics , statistics , artificial intelligence , computer science , composite material
Monte Carlo simulations are presented, dealing with phase diagrams of block copolymer melts and polymer blends, including the unmixing kinetics of the latter systems. The theoretical background is briefly reviewed: Ginzburg‐type criteria reveal that in mixtures of long flexible polymers a “crossover” occurs from mean‐field behavior (as described by Flory‐Huggins theory) to nonclassical Ising‐type behavior, and spinodal curves can be unusually sharp. This crossover is demonstrated by large scale simulations of the bond fluctuation model, and it is also shown that for symmetric mixtures the critical temperature scales with chain length as T c α N. The prefactor in this relation is distinctly smaller than predicted by Flory‐Huggins, but the Curro‐Schweizer integral equation theory prediction T c α √N is clearly ruled out. Tests of the Cahn theory on the initial stages of spinodal decomposition of polymer blends will also be reported. To conclude, the mesophase formation in block copolymers is discussed, and it is shown that the simulations agree very well with experiment. The pronounced chain stretching that already occurs in the disordered phase is compelling evidence against the validity of simple random phase approximation concepts for these systems. This shows how Monte Carlo simulations can assist in better understanding large classes of polymeric materials.