Phase separation dynamics in colloid-polymer mixtures: the effect of interaction range
Condensed Matter journal club
Phase separation dynamics in colloid-polymer mixtures: the effect of interaction range
- Event time: 11:30am
- Event date: 29th November 2013
- Speaker: Matthew Reeves (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Event details
Abstract
Colloid-polymer mixtures may undergo either fluid-fluid phase separation or gelation. This depends on the depth of the quench (polymer concentration) and the polymer-colloid size ratio. We present a real-space study of dynamics in phase separating colloid-polymer mixtures with medium- to long-range attractions (polymer-colloid size ratio qR = 0.45-0.89), with the aim of understanding the mechanism of gelation as the range of attraction is changed. In contrast to previous studies of short-range attractive systems, where gelation occurs shortly after crossing the equilibrium phase boundary, we find a substantial region of fluid-fluid phase separation. Upon quenching deeper, the system undergoes a continuous crossover to gel formation. We identify two regimes, 'classical' phase separation, where single particle relaxation is much faster than the dynamics of phase separation, and 'viscoelastic' phase separation, where demixing is slowed down appreciably due to slow dynamics in the colloid-rich phase. Particles at the surface of the strands of the network exhibit significantly greater mobility than those buried inside the gel strand which presents a method for coarsening.Soft Matter 9 pages 2076-2084 (2013)
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Authors
Isla Zhang, C. Patrick Royall, Malcolm A. Faers, Paul Bartlett
About Condensed Matter journal club
Given the diversity of research in the CM group, chosen topics vary widely. We tend to stick to high-impact journals - Nature, Science, PNAS and PRL have been popular - but this is not prescriptive..