Multiple dynamic regimes in colloid-polymer dispersions: New insight using X-ray photon correlation spectroscopy
- Department of Chemistry, Stony Brook University, Stony Brook New York; National Institute of Standards and Technology, Gaithersburg Maryland
- Department of Chemistry, Stony Brook University, Stony Brook New York; Department of Chemical Engineering, University of Massachusetts Amherst, Amherst Massachusetts
- Argonne National Laboratory, Advanced Photon Source, Argonne Illinois
- Department of Chemistry, Stony Brook University, Stony Brook New York; Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton New York
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
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1325247
- Journal Information:
- Journal of Polymer Science. Part B, Polymer Physics, Vol. 54, Issue 7; ISSN 0887-6266
- Publisher:
- Wiley
- Country of Publication:
- United States
- Language:
- English
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