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Title: Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations

Here, we have examined the formation and dissolution of gels composed of intermediate volume-fraction nanoparticles with temperature-dependent short-range attractions using small-angle x-ray scatter- ing (SAXS), x-ray photon correlation spectroscopy (XPCS), and rheology to obtain nanoscale and macroscale sensitivity to structure and dynamics. Gel formation after temperature quenches to the vicinity of the rheologically-determined gel temperature, T gel, was characterized via the slow-down of dynamics and changes in microstructure observed in the intensity autocorrelation functions and structure factor, respectively, as a function of quench depth (ΔT = T quench - T gel), wave vector, and formation time (t f). We find similar patterns in the slow-down of dynamics that maps the wave-vector-dependent dynamics at a particular ΔT and t f to that at other ΔTs and t fs via an effective scaling temperature, Ts. A single Ts applies to a broad range of ΔT and tf but does depend on the particle size. The rate of formation implied by the scaling is a far stronger function of ΔT than that of the attraction strength between colloids. Finally, we interpret this strong temperature de- pendence in terms of changes in cooperative bonding required to form stable, energetically favored, local structures.
 [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [4] ;  [3] ;  [1] ;  [3] ;  [2] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). X-Ray Science Division
  2. Florida State Univ., Tallahassee, FL (United States). College of Engineering, Chemical and Biomedical Engineering
  3. AGH Univ. of Science and Technology, Krakow (Poland)
  4. Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 119; Journal Issue: 17; Journal ID: ISSN 0031-9007
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science (SC); National Center for Research and Development, Poland
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1404748