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@ARTICLE{Banchio:862614,
      author       = {Banchio, Adolfo J. and Heinen, Marco and Holmqvist, Peter
                      and Naegele, Gerhard},
      title        = {{S}hort- and long-time diffusion and dynamic scaling in
                      suspensions of charged colloidal particles},
      journal      = {The journal of chemical physics},
      volume       = {148},
      number       = {13},
      issn         = {1089-7690},
      address      = {Melville, NY},
      publisher    = {American Institute of Physics},
      reportid     = {FZJ-2019-02883},
      pages        = {134902 -},
      year         = {2018},
      abstract     = {We report on a comprehensive theory-simulation-experimental
                      study of collective and self-diffusion in concentrated
                      suspensions of charge-stabilized colloidal spheres. In
                      theory and simulation, the spheres are assumed to interact
                      directly by a hard-core plus screened Coulomb effective pair
                      potential. The intermediate scattering function, fc(q, t),
                      is calculated by elaborate accelerated Stokesian dynamics
                      (ASD) simulations for Brownian systems where many-particle
                      hydrodynamic interactions (HIs) are fully accounted for,
                      using a novel extrapolation scheme to a macroscopically
                      large system size valid for all correlation times. The study
                      spans the correlation time range from the colloidal
                      short-time to the long-time regime. Additionally, Brownian
                      Dynamics (BD) simulation and mode-coupling theory (MCT)
                      results of fc(q, t) are generated where HIs are neglected.
                      Using these results, the influence of HIs on collective and
                      self-diffusion and the accuracy of the MCT method are
                      quantified. It is shown that HIs enhance collective and
                      self-diffusion at intermediate and long times. At short
                      times self-diffusion, and for wavenumbers outside the
                      structure factor peak region also collective diffusion, are
                      slowed down by HIs. MCT significantly overestimates the
                      slowing influence of dynamic particle caging. The dynamic
                      scattering functions obtained in the ASD simulations are in
                      overall good agreement with our dynamic light scattering
                      (DLS) results for a concentration series of charged silica
                      spheres in an organic solvent mixture, in the experimental
                      time window and wavenumber range. From the simulation data
                      for the time derivative of the width function associated
                      with fc(q, t), there is indication of long-time exponential
                      decay of fc(q, t), for wavenumbers around the location of
                      the static structure factor principal peak. The experimental
                      scattering functions in the probed time range are consistent
                      with a time-wavenumber factorization scaling behavior of
                      fc(q, t) that was first reported by Segrè and Pusey [Phys.
                      Rev. Lett. 77, 771 (1996)] for suspensions of hard spheres.
                      Our BD simulation and MCT results predict a significant
                      violation of exact factorization scaling which, however, is
                      approximately restored according to the ASD results when HIs
                      are accounted for, consistent with the experimental findings
                      for fc(q, t). Our study of collective diffusion is amended
                      by simulation and theoretical results for the
                      self-intermediate scattering function, fs(q, t), and its
                      non-Gaussian parameter α2(t) and for the particle mean
                      squared displacement W(t) and its time derivative. Since
                      self-diffusion properties are not assessed in standard DLS
                      measurements, a method to deduce W(t) approximately from
                      fc(q, t) is theoretically validated},
      cin          = {ICS-3},
      ddc          = {530},
      cid          = {I:(DE-Juel1)ICS-3-20110106},
      pnm          = {551 - Functional Macromolecules and Complexes (POF3-551)},
      pid          = {G:(DE-HGF)POF3-551},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:29626910},
      UT           = {WOS:000429359200053},
      doi          = {10.1063/1.5017969},
      url          = {https://juser.fz-juelich.de/record/862614},
}