Homogeneous nucleation and growth of ice from solutions. TTT curves, the nucleation rate, and the stable glass criterion

Abstract

Using water-in-oil emulsion samples to avoid, for the most part, heterogeneous nucleation, the crystallization of ice from a series of aqueous LiCl solutions has been studied isothermally, using differential calorimetry to monitor the process through the release of the heat of crystallization. The classical form of the time–temperature transformation TTT curve has thereby been directly observed for the first time for cystallizing supercooled liquids, and its movement with concentration changes has been determined. The conditions of observation are such that each ∼3 μ diameter droplet is multiply nucleated during the time of observation. At temperatures well above the ‘‘nose’’ of the TTT curve, where multiple nucleation does not occur, a new phenomenon—in which the rate of crystallization increases with increasing temperature of observation—is encountered. It seems probable that this is due to some heterogeneous process perhaps involving a reaction at the water–oil–surfactant interface to account for the positive temperature coefficient. The results in the homogeneously nucleated region correlate well with the much longer time scale studies reported recently on the basis of time-dependent conductivity measurements. Using approximate diffusivity data for water in this system, the combined crystallization data can be analyzed to yield nucleation rates which are in reasonable agreement with the results of recent small angle neutron scattering studies on this system.

Universal two-step crystallization of DNA-functionalized nanoparticles

“…Figure 3 shows the time crystallization time τ X and the amorphous relaxation time τ α for density ρd 3 = 0.5, which have been averaged over 10 independent trajectories. Such a plot is commonly referred to as a "time-temperaturetransformation" diagram 42,43 . We find that τ α is significantly smaller than τ X so that the clustered state can reach a metastable equilibrium prior to crystallization.…”

“…Accordingly, there is a very narrow slot that must be found for successfully nucleating the crystal state. The minimum, or "nose", in the crystallization time is ubiquitous in supercooled liquids [42][43][44][45] . If the system is cooled below T nose in a time less than τ nose , the system will not have adequate time to crystallize.…”

Interplay between Time-Temperature Transformation and the Liquid-Liquid Phase Transition in Water

“…A well-defined nose shape is visible, as measured for water solutions [11]. We also show the structural relaxation times τα as calculated from the self-intermediate scattering function Fs(Q, t) (closed circles).…”

“…The nucleation and growth of ice particles from aqueous solution has been extensively studied, and the "nose-shaped" time-temperature-transformation (TTT) curves have been measured [1,11,12]. The nonmonotonic relation between crystallization rate and supercooling depth results from the competition between the thermodynamic driving force for nucleation and the kinetics of growth [1].…”

The TTT Curves of the Heterogeneous and Homogeneous Crystallization of Lithium Disilicate – A Stochastic Approach to Crystal Nucleation

“…6 was used, while I 0 (HOM) was converted to a surface nucleation rate [I 0 (HOM, S) = I 0 (HOM, V) 2/3 × t V −1/3 (Krüger and Deubener, 2015a), the uncertainty of the conversion is less than 1%] and added to the HET nucleation rate. The shape of the overall time with a "double-nose" (black solid line) resembles those of an aqueous lithium chloride solution (MacFarlane et al, 1983) and of polybutylene terephthalate (Androsch et al, 2015). The double-nose diagram helps to explain the formation of a coast-island microstructure if lithium disilicate glass is heated at low rates from below T g in practice.…”