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, Tgel, 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 = Tquench - Tgel), wave vector, and formation time (tf). We find similar patterns in the slow-down of dynamics that maps the wave-vector-dependent dynamics at a particular ΔT and tf to that at other ΔTs and tfs 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.
Zhang, Qingteng, Bahadur, Divya, Dufresne, Eric M., et al., "Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations," Physical Review Letters 119, no. 17 (2017), https://doi.org/10.1103/PhysRevLett.119.178006
@article{osti_1425262,
author = {Zhang, Qingteng and Bahadur, Divya and Dufresne, Eric M. and Grybos, Pawel and Kmon, Piotr and Leheny, Robert L. and Maj, Piotr and Narayanan, Suresh and Szczygiel, Robert and Ramakrishnan, Subramanian and others},
title = {Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations},
annote = {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, Tgel, 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 = Tquench - Tgel), wave vector, and formation time (tf). We find similar patterns in the slow-down of dynamics that maps the wave-vector-dependent dynamics at a particular ΔT and tf to that at other ΔTs and tfs 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.},
doi = {10.1103/PhysRevLett.119.178006},
url = {https://www.osti.gov/biblio/1425262},
journal = {Physical Review Letters},
issn = {ISSN PRLTAO},
number = {17},
volume = {119},
place = {United States},
publisher = {American Physical Society (APS)},
year = {2017},
month = {10}}
Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, Vol. 359, Issue 1782https://doi.org/10.1098/rsta.2000.0812