Experimental study of the water in oil emulsions features by differential scanning calorimetry analysis

The present work proposes a differential scanning calorimetric (DSC) analysis approach in order to characterize a W/O emulsion in function of the vaporization temperature of the inner water droplets. The correlation between the most probable boiling temperatures of the droplets and their radii involves the evaluation of the story of the released energy during the vaporization process. The experimental set-up consists in a heat flow DSC system provided by a temperature programmable oven. A set of seven emulsions, containing the same amount of water, is classified in function of the dispersed water droplet diameters and tested several times. The resulting thermograms are statistically processed to obtain the most probable vaporization temperature for every emulsion in function of the dispersed water droplets size.The results show that the smaller the dispersed water droplet, the higher the vaporization temperature. Moreover, a notable degree of metastability, included in a range temperature from 5 to 10 °C, is pointed out and it is evident that it increases in reducing the dispersed water droplets size.

► A W/O emulsion is characterized by using differential scanning calorimetric technique.
► We examined relationship between boiling temperature and size of dispersed component.
► The smaller the dispersed water droplet, the higher the vaporization temperature.
► A degree of metastability of water is obtained and quantified.