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@INPROCEEDINGS{Kang:911210,
      author       = {Kang, Kyongok},
      title        = {{O}rientational {G}lasses and {P}hase {B}ehavior of
                      {C}harged {DNA}-{R}ods and their {R}esponse to {S}hear
                      {F}low},
      reportid     = {FZJ-2022-04515},
      year         = {2022},
      abstract     = {Long and thin, highly charged colloidal rods (fd-virus
                      particles) exhibit a glass transition at a concentration for
                      low ionic strengths, far above the isotropic-nematic
                      coexistence region. The morphology of the system consists of
                      chiral-nematic mesophases with different orientations. The
                      dynamics of single particles within the domains is arrested
                      due to initial caging of the charged rods by their neighbors
                      through long-ranged electrostatic interactions. The
                      microscopic dynamics of the orientation texture in domains
                      is found to freeze at the same concentration where single
                      particles are dynamically arrested [1,2]. Below the
                      glass-transition concentration, the initial morphology with
                      large shear-aligned domains breaks up into smaller domains,
                      and equilibrates after typically 50–100 hours. Two
                      dynamical modes are observed below the glass transition upon
                      equilibration. On approach of the glass-transition
                      concentration, the slow dynamical mode increases in
                      amplitude, while the amplitudes of a fast and slow modes
                      become equal at the glass transition [3-6]. In the first
                      part of this talk I will present experimental results on the
                      glass transition, the dynamics below the glass-transition,
                      and the phase diagram in the fd-concentration versus ionic
                      strength.The second part of the talk will be devoted to the
                      flow behavior of fd-suspensions in the glassy state. Such
                      suspensions exhibit stable inhomogeneous flow profiles,
                      depending on the applied shear rate: fracture and plug flow
                      at low shear rates, shear-banding at intermediate shear
                      rates, and a linear profile at sufficiently high shear rate.
                      These flow profiles coexist with Taylor vorticity bands
                      [7,8]. The mechanism for shear-banding in these systems with
                      a soft, long-ranged repulsive inter-particle potential is
                      not related to shear-gradient induced mass transport that
                      occurs in systems with a short-ranged interaction potential
                      [9], but is due to the classic banding scenario related to
                      strong shear-thinning behavior [7]. It is shown that there
                      is a subtle interplay between the stress originating from
                      inter-particle interactions within the domains and the
                      texture stress due to inter-domain interactions [8,10].
                      References: [1] Phys. Rev. Lett. 110, 015901 (2013) [2] Soft
                      Matter 9, 4401 (2013)[3] Soft Matter 10, 3311 (2014)[4]
                      Scientific Reports 11, 3472 (2021), [5] J. Phys. Commun. 5,
                      065011 (2021)[6] J. Phys. Commun. 6, 015001 (2022)[7] Phys.
                      Rev. Fluids 2, 043301 (2017)[8] J. Rheol. 66, 2, March 1st
                      (2022)[9] Soft Matter 10, 9470 (2014) [10] J. Phys. Commun.
                      5, 045011 (2021)},
      organization  = {Invited Seminar Talk, SNU, South
                       Korea, (South Korea)},
      subtyp        = {Invited},
      cin          = {IBI-4},
      cid          = {I:(DE-Juel1)IBI-4-20200312},
      pnm          = {5241 - Molecular Information Processing in Cellular Systems
                      (POF4-524)},
      pid          = {G:(DE-HGF)POF4-5241},
      typ          = {PUB:(DE-HGF)31},
      url          = {https://juser.fz-juelich.de/record/911210},
}