Thermodynamics Explains How Solution Composition Affects the Kinetics of Stochastic Ice Nucleation
Open access
Date
2023-07-06Type
- Journal Article
Abstract
The freezing of aqueous solutions is of great relevanceto multiplefields, yet the kinetics of ice nucleation, its first step, remainspoorly understood. The literature focuses on the freezing of microdroplets,and it is unclear if those findings can be generalized and extendedto larger volumes such as those used in the freezing of biopharmaceuticals.To this end, we study ice nucleation from aqueous solutions of tendifferent compositions in vials at the milliliter scale. The statisticalanalysis of the approximately 6,000 measured nucleation events revealsthat the stochastic ice nucleation kinetics is independent of thenature and concentration of the solute. We demonstrate this by estimatingthe values of the kinetic parameters in the nucleation rate expressionfor the selected solution compositions, and we find that a singleset of parameters can describe quantitatively the nucleation behaviorin all solutions. This holds regardless of whether the nucleationrate is expressed as a function of the chemical potential difference,of the water activity difference, or of the supercooling. While thechemical potential difference is the thermodynamically correct drivingforce for nucleation and hence is more accurate from a theoreticalpoint of view, the other two expressions allow for an easier implementationin mechanistic freezing models in pharmaceutical manufacturing. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000620174Publication status
publishedExternal links
Journal / series
The Journal of Physical Chemistry LettersVolume
Pages / Article No.
Publisher
American Chemical SocietyOrganisational unit
03484 - Mazzotti, Marco / Mazzotti, Marco
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