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.
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- Argonne National Lab. (ANL), Argonne, IL (United States). X-Ray Science Division
- Florida State Univ., Tallahassee, FL (United States). College of Engineering, Chemical and Biomedical Engineering
- AGH Univ. of Science and Technology, Krakow (Poland)
- Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy
- Publication Date:
- Grant/Contract Number:
- AC02-06CH11357
- Type:
- Accepted Manuscript
- Journal Name:
- Physical Review Letters
- Additional Journal Information:
- Journal Volume: 119; Journal Issue: 17; Journal ID: ISSN 0031-9007
- Publisher:
- 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
- Language:
- English
- Subject:
- 42 ENGINEERING
- OSTI Identifier:
- 1425262
- Alternate Identifier(s):
- OSTI ID: 1404748