Computer simulations of phase transitions of bulk and confined colloid-polymer systems

C. Y. Chou, T. T.M. Vo, Athanassios Z. Panagiotopoulos, M. Robert

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)275-290
Number of pages16
JournalPhysica A: Statistical Mechanics and its Applications
Volume369
Issue number2
DOIs
StatePublished - Sep 15 2006

All Science Journal Classification (ASJC) codes

  • Statistics and Probability
  • Condensed Matter Physics

Keywords

  • Colloid-polymer
  • Computer simulation
  • Depletion
  • Phase transition

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