## 3 Results and Discussion
### Thermal Stability of Electro-Sprayed mPCM  
The thermal stability of raw PCM, neat PCL electro-sprayed microparticles and mPCM were analyzed by TGA. TG and DTG curves of PCL microparticles, \(n\)-hexadecane (or \(n\)-eicosane) and \(n\)-hexadecane (or \(n\)-eicosane) based microparticles from chloroform and ethyl acetate are shown in Figure 5 (or Figure 6). The thermal behavior of \(n\)-hexadecane and \(n\)-eicosane displays single step degradation under N\({}_{2}\) atmosphere. The decomposition of \(n\)-alkanes, characterized by the onset temperature at 5% weight loss, starts at 151.6 and 178.8 \({}^{\circ}\)C for \(n\)-hexadecane, and \(n\)-eicosane, respectively. The main decomposition peaks of \(n\)-hexadecane and \(n\)-eicosane corresponding to the \(n\)-alkanes backbone decomposition take place at 246 and 269, and the maximum rates of decomposition are about 2.2, and 2.6% \({}^{\circ}\)C\({}^{-1}\), respectively. Furthermore, there is no residue for these compounds at over 280 \({}^{\circ}\)C. Under an inert atmosphere, PCL electro-sprayed microparticles display a single step degradation between 350 to 500 \({}^{\circ}\)C, corresponding to polymer pyrolysis with a maximum of degradation temperature at 411 or 413 \({}^{\circ}\)C, according to the solvent used in the electrospray process. The initial degradation temperatures (\(T_{onset}\)) were found to occur at 359 and 369 \({}^{\circ}\)C for samples prepared from ethyl acetate and chloroform, respectively. Furthermore, it seems that the solvent used has a few influences on the temperatures and maximum rate degradation (Table 3). \(N\)-alkanes based microparticles exhibit a two-step degradation. The first one, located from about 100 to 350 \({}^{\circ}\)C is ascribed to the PCM degradation, whereas the second one to the PCL matrix between 350 to 500 \({}^{\circ}\)C. The presence of PCL does not have an effect on the initial degradation temperature in the case of \(n\)-hexadecane, but a shift from 10 to 18 \({}^{\circ}\)C is observed for samples containing \(n\)-eicosane (Table 4). In the first degradation step, two types of phenomena occur, the first one corresponds to the degradation of \(n\)-alkane at the surface of the sample until 250 \({}^{\circ}\)C. When the temperature reaches 60-62 \({}^{\circ}\)C, PCL melts, and then all the microparticles samples are in a liquid state. Due to its lower density during the increase of temperature, a part of \(n\)-alkane chains can diffuse at the crucible surface and starts its degradation. The second phenomenon, between 250 to 300 \({}^{\circ}\)C, is related to the entrapped \(n\)-alkane chains in the PCL matrix and their entanglements, which required more thermal energy to be degraded since PCL acts as a barrier to prevent the degradation. In addition, with the increasing of \(n\)-alkane content, the maximum degradation rate in the first stage increases gradually; on the other hand, the second step is similar to that of the PCL. On the one hand, even if the initial degradation temperatures are close to the \(n\)-hexadecane, the maximum degradation temperatures in the first stage are significantly lower than the raw compound, increase with the increase in the loading content, and are not very dependent on the solvent used. On the other hand, when \(n\)-eicosane was used as a core compound, the initial thermal degradation temperatures are 10 to 18 \({}^{\circ}\)C higher than that of the raw compound one and decrease with the increase in the loading content. The maximum degradation temperatures in the first stage are 30 \({}^{\circ}\)C lower than \(n\)-eicosane one for low loading content and increase up to the \(n\)-alkane one at higher loading content. Furthermore, chloroform based microparticles have better thermal stability than the ethyl acetate-based one. This stability is related to the affinity between PCL and \(n\)-alkanes chains in the solvent solutions, which can favorize the entanglement during the electro-spraying process.