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Polydispersity effects in colloid-polymer mixtures

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Original languageEnglish
Article number194116
Pages (from-to)-
Number of pages6
JournalJournal of Physics: Condensed Matter
Volume23
Issue number19
DOIs
Publication statusPublished - 18 May 2011

Abstract

We study phase separation and transient gelation experimentally in a mixture consisting of polydisperse colloids (polydispersity: approximate to 6%) and non-adsorbing polymers, where the ratio of the average size of the polymer to that of the colloid is approximate to 0.062. Unlike what has been reported previously for mixtures with somewhat lower colloid polydispersity (approximate to 5%), the addition of polymers does not expand the fluid-solid coexistence region. Instead, we find a region of fluid-solid coexistence which has an approximately constant width but an unexpected re-entrant shape. We detect the presence of a metastable gas-liquid binodal, which gives rise to two-stepped crystallization kinetics that can be rationalized as the effect of fractionation. Finally, we find that the separation into multiple coexisting solid phases at high colloid volume fractions predicted by equilibrium statistical mechanics is kinetically suppressed before the system reaches dynamical arrest.

    Research areas

  • PHASE-BEHAVIOR, POLY(METHYL METHACRYLATE), LIGHT-SCATTERING, HARD-SPHERES, SMALL-ANGLE, DISPERSIONS, SYSTEMS, SIZE, FRACTIONATION, COEXISTENCE

ID: 1487327