Active phase separation in mixtures of chemically-interacting particles

EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS 48 (2019) S207-S207

Authors:

J Agudo-Canalejo, R Golestanian

Active phase separation in mixtures of chemically-interacting particles

EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS 48 (2019) S66-S66

Authors:

J Agudo-Canalejo, R Golestanian

Chemotaxis mediated interactions can stabilize the hydrodynamic instabilities in active suspensions

Soft Matter, 2019, 15, 3248-3255

Authors:

Mehrana Nejad, Ali Najafi

Abstract:

Ordered phases in active suspensions of polar swimmers are under long-wavelength hydrodynamic mediated instabilities. In this article, we show that chemical molecules dissolved in aqueous suspensions, as an unavoidable part of most wet active systems, can mediate long-range interactions and subsequently stabilize the polar phase. Chemoattractants in living suspensions and dissolved molecules in synthesized Janus suspensions are reminiscent of such chemical molecules. Communication between swimmers through the gradients of such chemicals is the foundation of this stabilization mechanism. To classify the stable states of such active systems, we investigate the detailed phase diagrams for two classes of systems with momentum conserving and non-conserving dynamics. Our linear stability analysis shows that the proposed stabilization mechanism can work for swimmers with different dynamical properties, e.g., pushers or pullers and with various static characteristics, e.g., spherical, oblate or prolate geometries.

DNA Systems Under Internal and External Forcing An Exploration Using Coarse-Grained Modelling Supervisor's Foreword

Chapter in DNA SYSTEMS UNDER INTERNAL AND EXTERNAL FORCING: AN EXPLORATION USING COARSE-GRAINED MODELLING, (2019) VII-+

Interplay of quenching temperature and drift in Brownian dynamics

EPL, 128 60006

Authors:

H. Khalilian, M. R. Nejad, A. G. Moghaddam and C. M. Rohwer

Abstract:

We investigate the non-equilibrium evolution of ideal Brownian particles confined
between two walls, following simultaneous quenches of the temperature and a constant external
force. We compute (analytically and in numeric simulations) the post-quench dynamics of the
density and the pressure exerted by the particles on the two walls perpendicular to the drift force.
For identical walls, symmetry breaking associated with the drift gives rise to unequal particle densities and pressures on the two walls. While the pressure on one wall increases monotonically after
the quench, on the other wall, depletion causes a non-monotonic dynamics with an overshooting at
finite times, before the long-term steady-state value is reached. For walls immersed in a Brownian
gas, the effective interaction force changes sign from repulsive at short times to attractive at late
times. These findings have potential applications in various soft matter systems or fluids with
charged Brownian particles, as well as carrier dynamics in semiconducting structures.