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1995
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Jan N, Glotzer SC, Poole PH, Coniglio A
Clusters and fractals in the Ising spin glass
FRACTALS-AN INTERDISCIPLINARY JOURNAL ON THE COMPLEX GEOMETRY OF NATURE 3 (3): 465-470 SEP 1995
[x] We define clusters in the Ising /-J spin glass model, and present evidence for a percolation transition of these correlated clusters coincident with the thermodynamic transition. At the transition temperature T-sg, we search for the appropriate clusters of quasifrozen spins which will percolate with exponents in the Ising spin glass universality class. These clusters should provide the dominant contribution to the nonlinear susceptibility, which diverges at T-sg, and result from the interference of clusters of parallel and antiparallel spins, as predicted by the Frustrated Percolation model.
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Glotzer SC
GLASSES AND THE GLASS-TRANSITION - CHALLENGES IN MATERIALS THEORY AND SIMULATION - PREFACE
COMPUTATIONAL MATERIALS SCIENCE 4 (4): 283-284 NOV 1995
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GLOTZER SC, CONIGLIO A
FRUSTRATION, CONNECTIVITY, AND THE GLASS-TRANSITION
COMPUTATIONAL MATERIALS SCIENCE 4 (4): 325-333 NOV 1995
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The concepts of connectivity, localization, and frustration are explored in relation to glass formation in amorphous materials, First, the concept of eigenclusters to geometrically characterize correlations in amorphous materials is introduced, and discussed in detail for both the Ising ferromagnet and Ising spin glass models. Second, a new, glass-forming percolation model that contains frustration as the essential ingredient, and exhibits two percolation transitions, is discussed. This new model gives new insights into frustrated systems, and applications to the Ising spin glass model and other glass-forming systems are discussed. In particular, we propose the possibility that the occurrence of a percolation-type transition at temperatures above the glass transition temperature may be a general feature of glass-forming systems, The important role of computer simulations in probing the mechanism of glass formation is emphasized.
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CASTELLANO C, GLOTZER SC
ON THE MECHANISM OF PINNING IN PHASE-SEPARATING POLYMER BLENDS
JOURNAL OF CHEMICAL PHYSICS 103 (21): 9363-9369 DEC 1 1995
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We reexplore the kinetics of spinodal decomposition in off-critical polymer blends through numerical simulations of the Cahn-Hilliard equation with the Flory-Huggins-De Gennes free energy functional. Even in the absence of thermal noise, the solution of the discretized equation of motion shows coarsening in the late stages of spinodal decomposition without evidence of pinning, regardless of the relative concentration of the blend components. This suggests this free energy functional is not sufficient to describe the physics responsible for pinning in real blends. (C) 1995 American Institute of Physics.
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GLOTZER SC, STAUFFER D, JAN N
MONTE-CARLO SIMULATIONS OF PHASE-SEPARATION IN CHEMICALLY REACTIVE BINARY-MIXTURES - REPLY
PHYSICAL REVIEW LETTERS 75 (8): 1675-1675 AUG 21 1995
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A Reply to the Comment by R. Lefever, D. Carati, and N. Hassani.
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DIMARZIO EA, YANG AJM, GLOTZER SC
MIXING PLATE-LIKE AND ROD-LIKE MOLECULES WITH SOLVENT - A TEST OF FLORY-HUGGINS LATTICE STATISTICS
JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 100 (2): 173-186 MAR-APR 1995
[x] Boehm and Martire have shown that the Flory-Huggins (FH) lattice model applied to mixtures of squares and rigid rods in solvent on a two dimensional lattice gives different results depending on whether rods or squares are placed first onto the lattice. This correct derivation places the validity of the FH model itself into question since the final result should be independent of the order of placement. An analysis of the FH model in terms of Poisson statistics suggests an alternative formula for the probability of successfully placing a rectangle into an area partially filled with other rectangles, which when incorporated into the FH counting procedure gives the exact thermodynamic result for the tiling of squares (i.e., no solvent and no rods). An attempt to solve the order of placement problem is made by solving the problem of one square plus any number of rods and then generalizing the statistics so that they are consistent with this result. Equations are given for squares plus rods plus solvent in both two and three dimensions. For plates plus solvent in three dimensions a purely entropy driven phase transition between an anisotropic layered phase and an isotropic phase is obtained. This transition is analogous to the isotropic to nematic liquid crystal phase transition in rigid rods. Our equations, when augmented by energy considerations, are useful for calculating the equilibrium properties of discotic systems, polymer-layered silicate composites, and the adsorption of plate like molecules onto surfaces.
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GLOTZER SC, DIMARZIO EA, MUTHUKUMAR M
REACTION-CONTROLLED MORPHOLOGY OF PHASE-SEPARATING MIXTURES
PHYSICAL REVIEW LETTERS 74 (11): 2034-2037 MAR 13 1995
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The role of externally-controlled chemical reactions in the selection of patterns in phase-separating mixtures is presented. Linearized theory and computer simulation show that the initial long-wavelength instability characteristic of spinodal decomposition is suppressed by chemical reactions, which restrict domain growth to intermediate length scales even in the late stages of phase separation. Our findings suggest that such reactions may provide a novel way to stabilize and tune the steady-state morphology of phase-separating materials.