TY - JOUR
T1 - Computer simulations of phase transitions of bulk and confined colloid-polymer systems
AU - Chou, C. Y.
AU - Vo, T. T.M.
AU - Panagiotopoulos, Athanassios Z.
AU - Robert, M.
N1 - Funding Information:
At Rice University, this work was supported by the National Science Foundation under Grants CTS-9700147 and CTS-0327487, and by the Welch Foundation (Houston, TX). At Princeton University this work was supported by the Department of Energy (Grant DE-FG02-01ER15121) and the Petroleum Research Fund administered by the American Chemical Society (Grant 38165-AC9). We thank K. Schweizer, I. Sleifzer and B. Widom for discussions, and O. Hehmeyer and J. Mourot for comments on the manuscript.
PY - 2006/9/15
Y1 - 2006/9/15
N2 - Grand canonical Monte Carlo, histogram reweighting and finite-size scaling methods are used to determine the phase transitions of bulk (three-dimensional) and confined (quasi-two-dimensional) neutral colloid-polymer systems. The colloids are modeled as hard spheres and the polymer molecules as hard chains, and the only attractive forces are effective ones induced by depletion effects. In contrast to the predictions of mean field and other approximate theories, the nature of the coexistence phases is found to not depend solely on the polymer-to-colloid size ratio, q, but on the colloid diameter, the polymer radius of gyration, and the polymer monomer size. The threshold values of q for the onset of liquid-liquid phase separation differ significantly from earlier predictions, and depend strongly on the dimensionality of space. Extrapolation to the "protein limit" of very small colloid and very long polymer indicates that immiscibility persists at this limit in three dimensions, while it does not always do so for confined systems.
AB - Grand canonical Monte Carlo, histogram reweighting and finite-size scaling methods are used to determine the phase transitions of bulk (three-dimensional) and confined (quasi-two-dimensional) neutral colloid-polymer systems. The colloids are modeled as hard spheres and the polymer molecules as hard chains, and the only attractive forces are effective ones induced by depletion effects. In contrast to the predictions of mean field and other approximate theories, the nature of the coexistence phases is found to not depend solely on the polymer-to-colloid size ratio, q, but on the colloid diameter, the polymer radius of gyration, and the polymer monomer size. The threshold values of q for the onset of liquid-liquid phase separation differ significantly from earlier predictions, and depend strongly on the dimensionality of space. Extrapolation to the "protein limit" of very small colloid and very long polymer indicates that immiscibility persists at this limit in three dimensions, while it does not always do so for confined systems.
KW - Colloid-polymer
KW - Computer simulation
KW - Depletion
KW - Phase transition
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U2 - 10.1016/j.physa.2006.01.079
DO - 10.1016/j.physa.2006.01.079
M3 - Article
AN - SCOPUS:33745684938
SN - 0378-4371
VL - 369
SP - 275
EP - 290
JO - Physica A: Statistical Mechanics and its Applications
JF - Physica A: Statistical Mechanics and its Applications
IS - 2
ER -