Ice nucleation at the silver iodide-aqueous solution interface

The ability of a solid substrate to activate ice nucleation in supercooled water depends on the extent to which it effects the orientation of the adsorbed water molecules into the ice like structure. The nucleating activity of silver iodide in supercooled water depends upon the potential determining silver and iodide ions. In order to find the influence of silver ion, nucleation experiments were conducted with varying concentration of silver ion from 10−2 to 10−12 M. The highest nucleating activity was observed at pAg6. The addition of isobutyl, n-butyl and n-propyl alcohols improved the nucleation temperature to −3°C. In addition to that the higher values of pAg were found to be more active than the lower pAg values in the presence of aliphatic alcohols. The exposition of AgI sols to ultra violet radiation affected the nucleation temperature depending upon the time of exposure. The mechanism of these effects is discussed in detail.