title: Validity of the Stokes-Einstein Relation in Soft Colloids up to the Glass Transition.
abstract: We investigate the dynamics of kinetically frozen block copolymer micelles of different softness across a wide range of particle concentrations, from the fluid to the onset of glassy behavior, through a combination of rheology, dynamic light scattering, and pulsed field gradient NMR spectroscopy. We additionally perform Brownian dynamics simulations based on an ultrasoft coarse-grained potential, which are found to be in quantitative agreement with experiments, capturing even the very details of dynamic structure factors S(Q,t) on approaching the glass transition. We provide evidence that for these systems the Stokes-Einstein relation holds up to the glass transition; given that it is violated for dense suspensions of hard colloids, our findings suggest that its validity is an intriguing signature of ultrasoft interactions.
authors.affiliation: JCNS-1 and ICS-1, Forschungszentrum Jülich, Leo-Brandt-Straße, 52425 Jülich, Germany.|JCNS-SNS, Oak Ridge National Laboratory, Bethel Valley Road, Oak Ridge, Tennessee 37831, USA.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Gupta
authors.affiliation: JCNS-1 and ICS-1, Forschungszentrum Jülich, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Stellbrink
authors.affiliation: CNR-ISC and Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Rome, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Zaccarelli
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Christos N
authors.initials: CN
authors.lastname: Likos
authors.affiliation: Centro de Investigaciones en Ciencias Básicas y Aplicadas, Universidad Antonio Nariño, Km 18 via Cali-Jamundí, 760030 Santiago de Cali, Colombia.
authors.forename: Manuel
authors.initials: M
authors.lastname: Camargo
authors.affiliation: Division of Physical Chemistry, Lund University, 22100 Lund, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Holmqvist
authors.affiliation: JCNS-1 and ICS-1, Forschungszentrum Jülich, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Allgaier
authors.affiliation: JCNS-1 and ICS-1, Forschungszentrum Jülich, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Willner
authors.affiliation: JCNS-1 and ICS-1, Forschungszentrum Jülich, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Richter