Issue 27, 2018

Different scenarios of dynamic coupling in glassy colloidal mixtures

Abstract

Colloidal mixtures represent a versatile model system to study transport in complex environments. They allow for a systematic variation of the control parameters, namely size ratio, total volume fraction and composition. We study the effects of these parameters on the dynamics of dense suspensions using molecular dynamics simulations and differential dynamic microscopy experiments. We investigate the motion of small particles through the matrix of large particles as well as the motion of large particles. A particular focus is on the coupling of the collective dynamics of small and large particles and on the different mechanisms leading to this coupling. For large size ratios, of about 1 : 5, and an increasing fraction of small particles, the dynamics of the two species become increasingly coupled and reflect the structure of the large particles. This is attributed to the dominant effect of the large particles on the motion of the small particles, which is mediated by the increasing crowding of the small particles. Furthermore, for moderate size ratios of about 1 : 3 and sufficiently high fractions of small particles, mixed cages are formed and hence the dynamics are also strongly coupled. Again, the coupling becomes weaker as the fraction of small particles is decreased. In this case, however, the collective intermediate scattering function of the small particles shows a logarithmic decay corresponding to a broad range of relaxation times.

Graphical abstract: Different scenarios of dynamic coupling in glassy colloidal mixtures

Supplementary files

Article information

Article type
Paper
Submitted
22 apr 2018
Accepted
14 jun 2018
First published
15 jun 2018

Phys. Chem. Chem. Phys., 2018,20, 18630-18638

Different scenarios of dynamic coupling in glassy colloidal mixtures

M. Laurati, T. Sentjabrskaja, J. Ruiz-Franco, S. U. Egelhaaf and E. Zaccarelli, Phys. Chem. Chem. Phys., 2018, 20, 18630 DOI: 10.1039/C8CP02559B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements