THE AGGREGATION PHENOMENA OF A CALCIUM SULFONATE ADDITIVE IN HYDROCARBON MEDIA BY DYNAMIC LIGHT-SCATTERING

The aggregation phenomena of a calcium sulfonate additive In several h ydrodynamic solvents was studied by dynamic light scattering. The Stok es-Einstein equation was used to calculate the average hydrocarbon rad ii. The aggregate size of calcium sulfonate in hexadecane was found to increase moderately with increasing concentrations. No critical micel lar concentration was observed at even concentrations as low as 0.2 mi llimole/liter. Within the temperature range studied, 15.8 degrees-47.1 degrees C, the aggregate size decreased moderately as the temperature increased. Hexane, heptane, nonane, dodecane, 1-heptene, 1-heptanol, 2-heptanone, and heptanoic acid were used to study the effect of the s olvent. A solvent with a longer chain length tended to result in a sma ller aggregate size. The polarity of the solvent also had a critical e ffect on the aggregate size. The results were discussed by using a the rmodynamic model for the aggregation of amphiphiles in nonaqueous solv ents.