Dynamic phase diagram of soft nanocolloids

Author(s)
Sudipta Gupta, Manuel Camargo, Joerg Stellbrink, Juergen Allgaier, Aurel Radulescu, Peter Lindner, Emanuela Zaccarelli, Christos N. Likos, Dieter Richter
Abstract

We present a comprehensive experimental and theoretical study covering micro-, meso-and macroscopic length and time scales, which enables us to establish a generalized view in terms of structure-property relationship and equilibrium dynamics of soft colloids. We introduce a new, tunable block copolymer model system, which allows us to vary the aggregation number, and consequently its softness, by changing the solvophobic-to-solvophilic block ratio (m: n) over two orders of magnitude. Based on a simple and general coarse-grained model of the colloidal interaction potential, we verify the significance of interaction length sigma(int) governing both structural and dynamic properties. We put forward a quantitative comparison between theory and experiment without adjustable parameters, covering a broad range of experimental polymer volume fractions (0.001 <= phi <= 0.5) and regimes from ultra-soft star-like to hard sphere-like particles, that finally results in the dynamic phase diagram of soft colloids. In particular, we find throughout the concentration domain a strong correlation between mesoscopic diffusion and macroscopic viscosity, irrespective of softness, manifested in data collapse on master curves using the interaction length sigma(int) as the only relevant parameter. A clear reentrance in the glass transition at high aggregation numbers is found, recovering the predicted hard-sphere (HS) value in the hard-sphere like limit. Finally, the excellent agreement between our new experimental systems with different but already established model systems shows the relevance of block copolymer micelles as a versatile realization of soft colloids and the general validity of a coarse-grained approach for the description of the structure and dynamics of soft colloids.

Organisation(s)
Computational and Soft Matter Physics
External organisation(s)
Institut Laue-Langevin (ILL), Sapienza University of Rome, Forschungszentrum Jülich, Oak Ridge National Laboratory , Universidad Antonio Nariño, Technische Universität München
Journal
Nanoscale
Volume
7
Pages
13924-13934
No. of pages
11
ISSN
2040-3364
DOI
https://doi.org/10.1039/c5nr03702f
Publication date
2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103029 Statistical physics, 210004 Nanomaterials
Keywords
ASJC Scopus subject areas
Materials Science(all)
Portal url
https://ucris.univie.ac.at/portal/en/publications/dynamic-phase-diagram-of-soft-nanocolloids(1c498d65-30e2-4c1c-9258-aec715414e28).html