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Title: Multiple dynamic regimes in colloid-polymer dispersions: New insight using X-ray photon correlation spectroscopy

We present an X-ray photon correlation spectros- copy (XPCS) study of dynamic transitions in an anisotropic colloid-polymer dispersion with multiple arrested states. The results provide insight into the mechanism for formation of repulsive glasses, attractive glasses, and networked gels of col- loids with weakly adsorbing polymer chains. In the presence of adsorbing polymer chains, we observe three distinct regimes: a state with slow dynamics consisting of finite particles and clusters, for which interparticle interactions are predominantly repulsive; a second dynamic regime occurring above the satu- ration concentration of added polymer, in which small clusters of nanoparticles form via a short-range depletion attraction; and a third regime above the overlap concentration in which dynamics of clusters are independent of polymer chain length. The observed complex dynamic state diagram is primarily gov- erned by the structural reorganization of a nanoparticle cluster and polymer chains at the nanoparticle-polymer surface and in the concentrated medium, which in turn controls the dynamics of the dispersion
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4]
  1. Department of Chemistry, Stony Brook University, Stony Brook New York; National Institute of Standards and Technology, Gaithersburg Maryland
  2. Department of Chemistry, Stony Brook University, Stony Brook New York; Department of Chemical Engineering, University of Massachusetts Amherst, Amherst Massachusetts
  3. Argonne National Laboratory, Advanced Photon Source, Argonne Illinois
  4. Department of Chemistry, Stony Brook University, Stony Brook New York; Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton New York
Publication Date:
OSTI Identifier:
1325247
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Polymer Science. Part B, Polymer Physics; Journal Volume: 54; Journal Issue: 7
Publisher:
Wiley
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE colloids; gels; nanoparticles