ABSTRACT
This article is a review of some results obtained by Differential Scanning Calorimetry (DSC) for characterizing the morphology of emulsions. In a classical DSC experiment, an emulsion sample is submitted to a regular cooling and heating cycle between temperatures that include freezing and melting of the dispersed droplets. By using the thermograms found in the literature for various emulsions, how to get information about the solidification and melting, the presence of solute, the emulsion type, the transfer of matter, the stability and the droplet size is shown.
Subject(s)
Calorimetry, Differential Scanning , Emulsions/chemistry , Models, Theoretical , Temperature , Time , Transition TemperatureABSTRACT
Emulsions are used in a wide range of applications and industries. Their size distribution is an important parameter because it influences most of the emulsion properties of emulsions. Several techniques of characterization are used to determine the granulometric distribution of emulsions, but they are generally limited to dilute samples and are based on complex algorithms. We describe a method that allows characterization of the droplet size distribution of emulsions using thermal analysis (thermogranulometry). This method permits the use of very concentrated samples without any dilution or perturbation of the system. We first define our method by a thermodynamic and kinetic approach. We studied a real system, i.e., crude oil emulsions, which form very concentrated, viscous, and opaque emulsions with water. We present a correlation between the size of droplets and their freezing temperature, corresponding to our system. Then we compare the size distributions obtained by our method with those derived by direct microscopy observations. The results obtained show that thermogranulometry may be an interesting method of characterization of emulsions, even for concentrated systems.
