Polydispersity Effects in Colloid-Polymer Mixtures

Abstract

We study phase separation and transient gelation in a mixture consisting of polydisperse colloids and non-adsorbing polymers, where the ratio of the average size of the polymer to that of the colloid is approximately 0.063. Unlike what has been reported previously for mixtures with somewhat lower colloid polydispersity, 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.

11 pages, 5 figures

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• Glasses in hard spheres with short-range attraction
• Crystallization of hard-sphere glasses
• Predicting phase equilibria in polydisperse systems
• Equilibrium phase behavior of polydisperse hard spheres
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Cited by in corpus (7)

• Charge regulation of nonpolar colloids
• Critical phase behavior in multi-component fluid mixtures: Complete scaling analysis
• The effects of polydispersity and metastability on crystal growth kinetics
• Simple analysis of scattering data with Ornstein-Zernike equation
• Spinodal fractionation in a polydisperse square well fluid
• Sedimentation path theory for mass-polydisperse colloidal systems
• Measuring local volume fraction, long-wavelength correlations and fractionation in a phase-separating polydisperse fluid