COMP 15 |
| We propose the following reason for the concentration dependence of the nonequilibrium freezing points of AF solutions. The crystal growth is spicular, parallel to [0001], and AF adsorption only inhibits growth normal to [0001]. Spicule growth rate depends upon supercooling at the spicule tip and upon the area of basal face, and is not directly affected by AF. However, AF adsorption at newly-created, non-basal surfaces limits spicule diameter. This depends upon adsorption rate, and hence upon AF concentration in solution. The supercooling at which spicule growth can occur depends upon the spicule diameter being small enough that the temperature at the tip is cold enough for fast growth parallel to [0001], yet large enough to provide an area big enough to support that growth by layer nucleation. This probably is how solution concentration determines the freezing point. Mechanistically, the nonequilibrium freezing point is a function of interface orientation, and we hope to provide a means of measuring that aspect of it. |
|
Antifreeze Proteins: A Memorial Symposium for Robert Feeney
8:30 AM-12:05 PM, Sunday, August 19, 2007 BCEC -- 162A, Oral
Division of Computers in Chemistry |