CLUSTER SIZE ESTIMATION IN BINARY SUPERSATURATED SOLUTIONS

Concentration gradients have been observed in a number of supersaturated binary solutions by several investigators. It is postulated that these gradients are due to the presence of solute clusters. The average size of these clusters have been determined by reanalyzing the data using the concept of number and weight average molecular weights. For all experimental observations to date, the calculations yielded a value of the number average cluster size ranging from 2 to 100 molecules. The number average cluster size is a strong function of the degree of association in the solution. The degree of association is a function of the solution temperature, time, the degree of supersaturation and possibly the thermal history of the solution. The calculated cluster sizes compare favorably to those determined independently from diffusivity observations.