## 1 Introduction  
Phase change materials (PCM) are inorganic or organic compounds, which can store or release a large amount of latent heat during their phase change transition induced with the surrounding temperature variations [1; 2; 3; 4; 5]. Thus, they are mainly used in space applications, smart textile structures, battery thermal management, industrial waste heat recovery, building energy conservation, and solar energy, in order to manage the thermal management due to their high energy storage density [6; 7; 8; 9]. The use of organic phase change materials has some limitations due to their low thermal conductivity, low density, high volatilization, and flammability [10; 11]. Since they are sometimes in their liquid phase, they cannot be applied on a substrate without being stabilized, which overcomes their drawbacks [12; 13; 14; 15; 16]. The PCM shape stabilization technique is one of the well-known ways to achieve the best benefits in energy storage in practical applications [17]. The PCM shape stabilizing materials can be obtained from various routes. Their microencapsulation improves heat transfer by increasing the surface-to-volume ratio [18]. Their incorporation into a polymer matrix is a low-cost technology. The use of nanomaterials in composite design improves their stability [19], while their impregnation into porous materials prevents their leakage, as well as the formulation of solid-solid phase change materials. The encapsulation step leads, not only to protect the active substance and to prevent leaching, but also to an increase in the specific surface contact area, and therefore, improve the thermal transfer management. Microencapsulation of PCM is mainly carried out via in-situ polymerization [18], interfacial polycondensation [20], sol-gel method [21; 22], simple or complex coacervation [23; 24], phase separation or suspension process [25; 26], and spray drying [27; 28; 29]. These methods have some drawbacks in the preparation of phase-change microcapsules, such as the complex shell formation process, the use of toxic substances or organic solvent, chemical additives and surfactants, and the difficulty in the control of structure, as well as morphology (i.e., size, shape, and porosity). Electrospraying method, as a one-step electrohydrodynamic atomization technology, has great potential and advantages to fabricate polymeric microcapsules or nanocapsules in a green and simple way [30; 31; 32; 33]. Furthermore, the control of the process and formulation parameters avoids particle aggregation and ensures a narrow and mono-dispersed particle size distribution under stable cone-jet mode. It also ensures the the shape, the surface state and porosity, and phase structure of microcapsules to be adjusted [34; 35]. Among the electrohydrodynamic atomization technologies, the electrospinning method is the most used with the phase change materials to prepare core-sheath structure nanofibers from a coaxial system [36; 37; 38]. The use of electrospray for PCM microencapsulation, even if some authors recognize it as a suitable method, is seldom described in the scientific literature [39]. In their works, [PERSON] et al. prepared \(n\)-nonadecane/sodium alginate mPCM, using melting coaxial electrospraying [39; 40; 41]. The formation of the shell was carried out via the cross-linking solidification reaction between alginate solution (outer liquid) and calcium chloride in collecting bath. The investigation of the alginate solution concentration and the optimization of the process parameters, controlling the mean diameter of the particles, allowed them to reach an encapsulation efficiency of about 59%, a phase change enthalpy of their capsules about 88 J/g, and a mean diameter between 200 to 700 \(\upmu\)m. \(N\)-octadecane was successfully entrapped in a polyamic acid shell via a coaxial electrospraying process [42]. The authors observed that the core feed rate affected the surface morphology as well as the mean diameter of the capsules.