화학공학소재연구정보센터
Journal of Chemical Physics, Vol.117, No.11, 5319-5327, 2002
Liquid-to-crystal nucleation: A new generation lag-time apparatus
The statistics of liquid-to-crystal nucleation are examined using a new generation automated lag-time apparatus denoted ALTA 4. Two modes of operation are described and implemented. A single 200 mul sample of distilled water is cooled repeatedly at a constant rate, alpha, until the sample freezes. This cycle is repeated many hundreds of times, to generate the reliable and reproducible statistics for nucleation. From a single experiment, under a single testable approximation, we extract the functional form which characterizes the average lag-time, , as a function of the degree of supercooling DeltaT below the equilibrium freezing temperature, T-f. These data and the analysis yield, from a single experiment, a profile for the average lag-time, , as a function of change in temperature, DeltaT. Identical results are obtained over more than an order of magnitude of cooling rates alpha, from 0.6 to 7.5 K min(-1) (0.01-0.125 K s(-1)).