Motility-Induced Phase Separation

By M. E. Cates, J. Tailleur. 2014

1,518 citations recorded by the source corpus.

Self-propelled particles include both self-phoretic synthetic colloids and various microorganisms. By continually consuming energy, they bypass the laws of equilibrium thermodynamics. These laws enforce the Boltzmann distribution in thermal equilibrium: The steady state is then independent of kinetic parameters. In contrast, self-propelled particles tend to accumulate where they move more slowly. They may also slow down at high density for either biochemical or steric reasons. This creates positive feedback, which can lead to motility-induced phase separation (MIPS) between dense and dilute fluid phases. At leading order in gradients, a mapping relates variable-speed, self-propelled particles to passive particles with attractions. This deep link to equilibrium phase separation is confirmed by simulations but generally breaks down at higher order in gradients: New effects, with no equilibrium counterpart, then emerge. We give a selective overview of the fast-developing field of MIPS, focusing on theory and...

Subfields: Condensed Matter Physics, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/b01f330edc15b67c97d73d3e1010eb9a553ce722

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Citations in the corpus

Temperature in and out of equilibrium: A review of concepts, tools and attempts (2017, background): “Interestingly, a role of a certain relevance has been played by equilibrium-like or equilibrium-inspired models, where the intrinsic non-equilibrium condition of active systems has been neglected or drastically reduced [301,297].”
Theories of binary fluid mixtures: from phase-separation kinetics to active emulsions (2017, background): “…bottom-up coarse-graining instead suggests a slightly different structure in which TRS is broken through terms in the deterministic sector that are incompatible with the existence of a free energy, meaning that no Boltzmann distribution is possible (Marchetti et al. 2013; Cates & Tailleur 2015).”
Entropy production in field theories without time reversal symmetry: Quantifying the non-equilibrium character of active matter (2016, background): “(Such particles can phase separate even when their interactions are purely repulsive [12].”
Active Particles in Complex and Crowded Environments (2016, background): “d exibility of the passive particles on the eects of an active bath (Section IV.C.6). Interesting reviews on some aspects of the topics covered in this section can be found in Bialke et al. (2015), Cates and Tailleur (2015), and Elgeti et al. (2015). 1. Active doping Doping of colloidal suspensions ”
Cluster Phases and Bubbly Phase Separation in Active Fluids: Reversal of the Ostwald Process (2018, background): “[3,4,32], we argue that the hard-core interactions effectively coarse grain into an effective propulsion speed vðr; 1⁄2ρ Þ that functionally depends on the coarse-grained density ρ of active particles.”
The statistical physics of active matter: From self-catalytic colloids to living cells (2017, background): “Amicroscopic phenomenological picture has emerged to describeMIPS.”
Topological active matter (2020, background): “This approach has lead to striking theoretical predictions such as the existence of two-dimensional ordered flocks [55, 56], giant number fluctuations [34, 57], spontaneous flow instabilities of active suspensions [58, 59], motility induced phase separation of purely repulsive particles [60, 61], an”
Classical dynamical density functional theory: from fundamentals to applications (2020, background): “Moreover, Dean’s results are of importance in active matter physics [248–255].”