Journal Article

FZJ-2015-05341

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Dynamic phase diagram of soft nanocolloids

Gupta, S. (Corresponding author)FZJ* ; Camargo, M. ; Stellbrink, J.FZJ* ; Allgaier, J.FZJ* ; Radulescu, A.FZJ* ; Lindner, P. ; Zaccarelli, E. ; Likos, C. N. ; Richter, D.FZJ*

2015
RSC Publ. Cambridge

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Please use a persistent id in citations: doi:10.1039/C5NR03702F

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 σint 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 ≤ ϕ ≤ 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 σint 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.

Keyword(s): Health and Life (1st) ; Health and Life (1st) ; Soft Condensed Matter (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)
3. Neutronenstreuung (ICS-1)

Research Program(s):

1. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
3. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. KWS-1: Small angle scattering diffractometer (NL3b)
2. KWS-2: Small angle scattering diffractometer (NL3ao)

Appears in the scientific report 2015

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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