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We present investigations of the kinetics of the colloidal sol-to-gel transition by combining small angle static light scattering (SASLS) and dynamic light scattering (DLS) techniques. Dilute monomer volume fractions were used to allow for a full investigation of the gelation to obtain all possible kinetic regimes. Our data verify the predictions of a kinetic theory, the ideal gel point (IGP) theory, where three regimes of kinetics are expected. We observe the first regime, the well-known cluster-dilute regime, with a kinetic exponent of z = 1. Followed by a cluster-dense regime with an enhanced kinetics and z ’ 2. Finally, a gelation regime is observed where the aggregate growth slows and ceases to grow at the IGP predicted size, Rg,G. These results quantitatively verify the IGP theory. We conclude that kinetic description provides a complete theory of the gelation process from sol to gel.
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Kinetics of sol-to-gel transition in irreversible particulate systems
A comprehensive theory encompassing the kinetics of the sol-to-gel transition is yet to be formulated due to break-down of the mean-field Smoluchowski Equation. Using high temporal-resolution Monte Carlo simulation of irreversible aggregation systems, we show that this transition has three distinct regimes with kinetic exponent z 2 1 ½ ; 2Þ corresponding to aggregation of sol clusters proceeding to the ideal gel point (IGP); z 2 ½2; 5:7Þ for gelation of sol clusters beyond IGP; and z 2 ½2; 3:5Þ for a hitherto unidentified regime involving aggregation of gels when monomer-dense. We further establish universal power-law scaling relationships that connect the kinetics of these three regimes. Improved parameterizations are performed on the characteristic timescale parameters that define each regime.
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- Award ID(s):
- 1649783
- PAR ID:
- 10160899
- Date Published:
- Journal Name:
- Journal of colloid and interface science
- Volume:
- 550
- ISSN:
- 0021-9797
- Page Range / eLocation ID:
- 57–63
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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