Active binary switching of soft colloids: stability and structural properties
Metadatos
Mostrar el registro completo del ítemEditorial
Royal Society of Chemistry
Fecha
2021-07-29Referencia bibliográfica
Soft Matter, 2021, 17, 7682. DOI: [10.1039/d1sm00670c]
Patrocinador
state of BadenWurttemberg through bwHPC; German Research Foundation (DFG) INST 39/963-1 FUGG; University of Granada PPVS2018-08; Plan Andaluz de Investigacion, Desarrollo e Innovacion of the Junta de Andalucia PY20_00241Resumen
We employ reactive dynamical density functional theory (R-DDFT) and reactive Brownian dynamics
(R-BD) simulations to study the non-equilibrium structure and phase behavior of an active dispersion of
soft Gaussian colloids with binary interaction switching, i.e., we consider a one-component colloidal
system in which every particle can individually switch stochastically between two interaction states
(here, sizes ‘big’ and ‘small’) at predefined rates. We consider the influence of switching activity on the
inhomogeneous density profiles of the colloids confined by various external potentials, as well as on
their pair structure and phase behavior in bulk solutions. For the latter, we extend the R-DDFT method
to incorporate the Percus test-particle route. Our results demonstrate that switching activity strongly
modifies the steady-state density profiles and structural (pair) correlations. In particular, the switching
rate interpolates from a near-equilibrium binary colloidal mixture of two states at very low rates to a
non-equilibrium, ‘one-state liquid’ at very high rates characterized by one, average interaction size. The
latter limit can be described by an equivalent effective one-component (EOC) equilibrium system, for
which the exact analytical expression for the effective pair potential is a diffusion-weighted
superposition of the active systems’ pair potentials. This leads to the interesting fact that under certain
conditions an interacting switching system can behave like a non-interacting (ideal) gas in the limit of
high switching rates. Moreover, for colloids that are unstable (i.e., demix) near equilibrium, we
demonstrate that phase separation and micro-clustering in both confinement and bulk can be
dynamically controlled by the switching rate, and vanish for high rates. All R-DDFT results are in
excellent agreement with our R-BD simulations.