Soft Condensed Matter
O'Connor, Alvarez, and Robbins Reply to Xu et al. (arXiv:1808.05390) (1902.04020v1)
Thomas C. O'Connor, Nicolas J. Alvarez, Mark O. Robbins
2019-02-11
The preceding Comment by Xu et al. (Phys. Rev. Lett. 122, 059803 (2019); arXiv:1808.05390) erroneously applies the entropic stress expression in our Letter (T.C. O'Connor et al., Phys. Rev. Lett. 121, 047801 (2018); arXiv:1806.09509) to transient stress. In addition, the authors only apply this expression at extreme extension rates where we clearly showed deviations from the entropic stress expression for steady-state extensional flow. Hence the surprisingly minor discrepancies noted in the Comment between observed and "predicted" stress are entirely expected and have no bearing on the discussion or conclusions in our Letter.
Transient response of an electrolyte to a thermal quench (1902.03963v1)
Mathijs Janssen, Markus Bier
2019-02-11
We study the transient response of an electrolytic cell subject to a small, suddenly-applied temperature increase at one of its two bounding electrode surfaces. An inhomogeneous temperature profile then develops, causing, via the Soret effect, ionic rearrangements towards a state of polarized ionic charge density
and local salt density
. We derive analytical approximations to
, and the electrostatic potential
for early
and late
times as compared to the relaxation time
of the temperature. We challenge the conventional wisdom that the typically large Lewis number, the ratio
of thermal to ionic diffusivities, of most liquids implies a quickly-reached steady-state temperature profile onto which ions relax slowly. Though true for the evolution of
of thermal to ionic charge relaxation times involves, besides
, the salt concentration-dependent Debye length
, which can be varied over many decades. Consequently, one can access both
(if
, with
being the electrode separation), for which the temperature relaxes quickly and our analytical
-expressions apply for most of the transient response, as well as
(if
). In the latter scenario, corresponding to several prior experimental setups, a significant portion of the transient response of the cell falls in the
-regime, for which our approximated
Eshelby ensemble of highly viscous flow out of equilibrium (1902.02746v2)
U. Buchenau
2019-02-07
The recent description of the highly viscous flow in terms of irreversible structural Eshelby rearrangements is extended to calculate the heat capacity of a glass former at a constant cooling rate through the glass transition. The result is compared to measured data from the literature, showing that the explanation works both for polymers and other glass formers.
Critical motility-induced phase separation belongs to the Ising universality class (1810.06112v2)
Benjamin Partridge, Chiu Fan Lee
2018-10-14
A collection of self-propelled particles with volume exclusion interactions can exhibit the phenomenology of gas-liquid phase separation, known as motility-induced phase separation (MIPS). The non-equilibrium nature of the system is fundamental to the phase transition, however, it is unclear whether MIPS at criticality contributes a novel universality class to non-equilibrium physics. We demonstrate here that this is not the case by showing that a generic critical MIPS belongs to the Ising universality class with conservative dynamics.
A new look at effective interactions between microgel particles (1902.03784v1)
Maxime J. Bergman, Nicoletta Gnan, Marc Obiols-Rabasa, Janne-Mieke Meijer, Lorenzo Rovigatti, Emanuela Zaccarelli, Peter Schurtenberger
2019-02-11
Thermoresponsive microgels find widespread use as colloidal model systems, because their temperature-dependent size allows facile tuning of their volume fraction "in situ". However, an interaction potential unifying their behavior across the entire phase diagram is sorely lacking. Here we investigate microgel suspensions in the fluid regime at different volume fractions and temperatures, and in the presence of another population of small microgels, combining confocal microscopy experiments and numerical simulations. We find that effective interactions between microgels are clearly temperature dependent. In addition, microgel mixtures possess an enhanced stability compared to hard colloid mixtures - a property not predicted by a simple Hertzian model. Based on numerical calculations we propose a multi-Hertzian model, which reproduces the experimental behaviour for all studied conditions. Our findings highlight that effective interactions between microgels are much more complex than usually assumed, displaying a crucial dependence on temperature and the internal core-corona architecture of the particles.
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