## 3 Results and Discussions  
### DSC Thermogram Interpretation  
DSC is a technique to measure the thermal properties of materials to establish a connection between temperature absorbed or emitted during controlled heating, and the specific physical properties of the substance. It is the only method for direct determination of enthalpy associated with the process of interest [16; 17]. The principle of the DSC is based on the measurement of heat flux required for the temperature of the sample increases or decreases. This heat flux is directly proportional to the heat capacity of the material for a given temperature. The amount of heat involved depends on whether the process is exothermic or endothermic. By observing the difference in energy flow between the sample and reference, the thermal properties of materials can be measured [18]. DSC is widely used for the decomposition behavior determination of the polymer [19; 20; 21; 22]. In the emulsion system, DSC monitors the solidification process inside the droplets and calculates the temperature dependence of the nucleation rate [23]. The sample is regularly cooled below and heated above to its solid-liquid equilibrium temperature to determine the freezing, \(\mathrm{T_{f}}\) and melting temperature, \(\mathrm{T_{m}}\). The energies involved are recorded as peaks presented in exothermic and endothermic flows versus temperature. The droplet sizes and the way they evolved with time might be determined from the peaks obtained [14]. A DSC thermogram of a freezing water droplet is presented in Figure 1. The straight line in the figure indicated there is no water droplet that has been frozen before \(\mathrm{T_{1}}\). As the temperature is lower than 0 \({}^{\circ}\)C, the ice formation starts to form inside the droplet even in a very small number because the nucleation rate is nearly zero [23]. The nucleation rate is drastically increasing between temperature \(\mathrm{T_{1}}\) and \(\mathrm{T_{2}}\). All the droplets have full frozen as \(\mathrm{T_{2}}\) is attained, but it depends on the sensibility of the calorimeter used. The exothermic peak (Figure 1, C is the energy released and the area below the baseline (Figure 1, C) is the energy to heat of the sample [24]. The \(\mathrm{T^{*}}\) refers to the mean freezing temperature because the maximum number of droplets are frozen in this temperature [25]. According to [PERSON], 2009 [13] the \(\mathrm{T^{*}}\) may be correlated to the mean diameter of dispersed droplets because the maximum number of droplets are expected to freeze around this temperature. Figure 2 shows the thermogram of a bulk aqueous phase (in dotted line) and a sample W/O emulsion (in solid line). During the cooling process from 30 to \(-\)60 \({}^{\circ}\)C, water freezes at different temperatures depending on their size. For 30 mg of the sample aqueous solution with diameter, \(\mathcal{O}\) = 1 mm, a mean freezing temperature, T* is found at \(-\)14 \({}^{\circ}\)C (Figure 2, _i_). For 30 mg of the sample W/O emulsion with a mean droplet size distribution, D\({}_{43}\) = 4 \(\mu\)m, T* is found \(-\)39 \({}^{\circ}\)C (Figure 2, _ii_), while the oil continuous phase freezes at T* = \(-\)50 \({}^{\circ}\)C (Figure 2, _iii_). During the heating process, the temperature returns to the initial one, all the water melts at the same temperature, namely T\({}_{\text{m}}\) = 0 \({}^{\circ}\)C, as seen in Figure 2, \(v\) for the water dispersed droplets of sample emulsion and Figure 1B, _vi_ for the bulk aqueous phase. And the melting temperature of the oil continuous phase is found at T\({}_{\text{m}}\) = \(-\)33 \({}^{\circ}\)C (Figure 2, _iv_). According to [PERSON] et al., 2014 [23], freezing is the result of nucleation phenomena, temperature variations can induce a change in morphology, consequently, all the water droplets do not freeze at the equilibrium point, so their freezing temperatures are scattered.