## 4 Conclusions  
In the present study, a CAR was encapsulated in SAN nanocapsules through the coaxial electrospraying for self-healing purposes. Morphological studies revealed that the uniform core-shell nanocapsules with a mean diameter of \(708\pm 252\) were prepared, while the core content and encapsulation yield were measured to be 32% and 69%, respectively. In addition, morphological studies revealed the formation of the rough outer surface, which made them suitable for better dispersion and enhanced self-healing performance, and a soft inner surface of the nanocapsules, confirming the successful encapsulation process without any reaction between shell and core materials. The FTIR and TGA test results confirmed the presence of both SAN and CAR in the prepared nanocapsules and the thermal stability of the capsules up to 270 \({}^{\circ}\)C. Furthermore, the DSC test results confirmed the reactivity of released healing agent from nanocapsules. The evaluation of the mechanical properties of the coatings showed that the incorporation of the nanocapsules decreased both the adhesion of the coating to the substrate and bending elongation of the coatings. The evaluation of the self-healing performance revealed that the coatings containing nanocapsules have the self-healing ability during the salt spray test. In addition, the EIS test results showed that the coating has the autonomous ability to heal in both NaCl and HCl media. The best self-healing performance occurred for the coating containing 2 wt.% nanocapsules in the NaCl solution with 99% healing efficiency. In contrast, for HCl media, the best self-healing performance was observed for the coating containing 1 wt.% of the nanocapsules with 95% healing efficiency. **Supplementary Materials:** The following are available online at [[http://www.mdpi.com/2076-3417/10/9/3171/s1](http://www.mdpi.com/2076-3417/10/9/3171/s1)]([http://www.mdpi.com/2076-3417/10/9/3171/s1](http://www.mdpi.com/2076-3417/10/9/3171/s1)), Figure S1: FESEM images of the prepared capsules at 22 kV, 0.6 and 0.05 mL/h, and 15 cm of applied voltage, flow rates of the shell and core solutions, and the distance of needle to the collector, respectively at the shell solution concentration of (a) 4 \(w\)/\(\psi\) %; (b) 6 \(w\)/\(\psi\) %. Figure S2: FESEM images of the prepared capsules at 0.6 and 0.05 mL/h, 15 cm, and 5 \(w\)/\(\psi\) % of flow rates of the shell and core solutions, the distance of needle to the collector, and concentration of the shell solution, respectively at the applied voltage of (a) 20 kV (tripping mode) and (b) 24 kV (multi-jet mode). Figure S3: FESEM images of the prepared capsules at 22 kV, 15 cm, and 5 \(w\)/\(\psi\) % of the applied voltage, the distance of needle to the collector, and concentration of the shell solution, respectively. The flow rate of the core solution is 0.05 mL/h while the flow rate of shell solution is; (a) 0.5 mL/h; (b) 0.7 mL/h and. The flow rate of shell solution is 0.6 mL/h and the flow rate of core solution is; (c) 0.04 mL/h; (d) 0.06 mL/h. Figure S4: FESEM images of the prepared capsules at 22 kV, 0.6 and 0.05 mL/h, and 5 \(w\)/\(\psi\) % of the applied voltage, flow rates of the shell and core solutions, and concentration of the shell solution, respectively at the distance between needle to the collector of (a) 13 cm, and (b) 17 cm. Figure S5: FESEM images of the prepared nanocapsules at 22 kV, 0.6 and 0.05 mL/h, 15 cm, and 5 \(w\)/\(\psi\) % of the applied voltage, flow rates of the shell and core solutions, the distance of needle and collector, and concentration of the shell solution, respectively while the solvent was (a) DCM, and (b) DMF (wet collector and incapability of the process for encapsulating the healing agent). **Author Contributions:** Conceptualization, R.M., S.N.K. and R.E.N. ; methodology R.M., S.N.K., R.E.N., and M.S.K. ; software, R.M., R.E.N., M.S.K. ; validation, R.E.N., M.S.K., and O.D. ; formal analysis, R.M., R.T.; investigation,R.M., and R.T.; resources, S.N.K. ; data curation, R.E.N., M.S.K., R.T., and O.D.