Freezing of Oil-Water and Oil-Saline Emulsions Lillian Truong and Colin I?.Phillips’ Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto M5S 1A4, Ont., Canada
The effect of freeze-thaw cycles on the oil content of an emulsion (“breakage”) and on the oil droplet size distribution was determined. The method of Lien and Phillips was used to measure the droplet size distributions of emulsions of tetralin in water and in saline (3.5% NaCl) in both aging and freeze-thaw cycles. Oil-to-aqueous-phase ratios of 1050% by volume were investigated, using Tween-80 at its critical micelle concentration to stabilize the emulsions. After freeze-thaw cycles, a decrease in the specific surface of the droplets was observed (for example from 8.9 X lo4 to 0.67 lo4 cm2/g for the size range 0.75-12.5-pm diameter). Coalescence appears to be the most important breaking mechanism for emulsions in such a cycle. Repetition of cycles did not cause further emulsion breakage but resulted in a gradual shift of the peak in the particle size curve from
