Active interaction switching controls the dynamic heterogeneity of soft colloidal dispersions
Metadatos
Mostrar el registro completo del ítemEditorial
Royal Society of Chemistry
Fecha
2021-12-01Referencia bibliográfica
Soft Matter, 2022, 18, 397. [https://doi.org/10.1039/d1sm01507a]
Patrocinador
BadenWurttemberg through bwHPC; German Research Foundation (DFG) INST 39/963-1 FUGG WO 2410/2-1 FOR 5099 431945604; Spanish Ministry and Agencia Estatal de Investigacion (AEI) PID2020-113681GB-I00 FIS2017-84256-P; Junta de Andalucia; European Regional Development Fund Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia PY20-00241 A-FQM-90-UGR20 A-FQM175-UGR18 SOMM17/6105/UGR; University of Granada PPVS2018-08Resumen
We employ Reactive Dynamical Density Functional Theory (R-DDFT) and Reactive Brownian Dynamics
(R-BD) simulations to investigate the dynamics of a suspension of active soft Gaussian colloids with
binary interaction switching, i.e., a one-component colloidal system in which every particle stochastically
switches at predefined rates between two interaction states with different mobility. Using R-DDFT we
extend a theory previously developed to access the dynamics of inhomogeneous liquids [Archer et al.,
Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., 2007, 75, 040501] to study the influence of the
switching activity on the self and distinct part of the Van Hove function in bulk solution, and determine
the corresponding mean squared displacement of the switching particles. Our results demonstrate that,
even though the average diffusion coefficient is not affected by the switching activity, it significantly
modifies the non-equilibrium dynamics and diffusion coefficients of the individual particles, leading to a
crossover from short to long times, with a regime for intermediate times showing anomalous diffusion.
In addition, the self-part of the van Hove function has a Gaussian form at short and long times,
but becomes non-Gaussian at intermediates ones, having a crossover between short and large
displacements. The corresponding self-intermediate scattering function shows the two-step relaxation
patters typically observed in soft materials with heterogeneous dynamics such as glasses and gels. We
also introduce a phenomenological Continuous Time Random Walk (CTRW) theory to understand the
heterogeneous diffusion of this system. R-DDFT results are in excellent agreement with R-BD
simulations and the analytical predictions of CTRW theory, thus confirming that R-DDFT constitutes a
powerful method to investigate not only the structure and phase behavior, but also the dynamical
properties of non-equilibrium active switching colloidal suspensions.