## 3 Results and Discussion  
The Effective Young's modulus (\(E\)) at 23 \({}^{\circ}\)C and 60 \({}^{\circ}\)C was evaluated for three different samples at each temperature on the top of the microcapsules. In Figure 1, the histograms displaying the results for the sample composed of PMMA and tetracosane (1:3) for both temperatures are shown. This is a graphical representation of the data distribution as a probability distribution estimation of a quantitative variable. The difference obtained when increasing the temperature is noticeable. At 23 \({}^{\circ}\)C, the \(E\) value of the PMMA microcapsules had a mean of 2.7 GPa, while at 60 \({}^{\circ}\)C this value dramatically decreased to 0.1 GPa. That is, there was a 96% of \(E\) reduction between the temperatures. The histograms showing the results for PS and tetracosane (1:3) are shown in Figure 2. In this case, \(E\) at 23 \({}^{\circ}\)C had an average value of 1.5 GPa, while \(E\) at 60 \({}^{\circ}\)C was 1.1 GPa. This means a 27% reduction of Effective Young's Modulus between the temperatures. Accordingly, and only taking into account the \(E\) values, it would be better to use polystyrene (PS) as a shell in a MPCM system due to the \(E\) value not decreasing so abruptly when the temperature rises. Additionally, tests were performed to evaluate the maximum force that can be applied on the top of the microcapsule before breaking it. In the case of the MPCM formed using PMMA as the shell and tetracosane as a PCM, this force at 23 \({}^{\circ}\)C was 31.2 \(\upmu\)N, as shown in Figure 3. In a typical loading curve, the applied force is proportional to the deflection error, and \(Z\) (nm) is the penetration of the tip inside the sample. Four subsections can be taken into account in this kind of graph: (a) No contact between sample and tip. In the graph, this point (a) is marked with an arrow and an image of the sample before applying forces has also been added. This is the first part of the blue continuous line; (b) Plastic deformation or plastic penetration of the sample. There is a change in the slope, which can be defined as the maximum force that can be applied to the sample. This is the area between two vertical discontinuous lines, and is also marked with an arrow; (c) Deformation of the sample; (d) Retraction of the AFM probe until there is no contact between the tip and the sample, which is marked by a red discontinuous line. Most of the time, the end of line (d) and the beginning of line (a) are overlapped. Figure 1: Results for PMMA:tetracosane (1:3): (a) 3D image tested; (b) [PERSON]’s modulus results at 23 \({}^{\circ}\)C; (c) [PERSON]’s modulus results at 60 \({}^{\circ}\)C.  
The same test was performed at 60 \({}^{\circ}\)C, and the result was 11.4 \(\upmu\)N, 63.5% less than that obtained at room temperature. The graphic representation is shown in Figure 4.  
Figure 3: Mechanical testing of the elastic-plastic region by AFM of the MPCM composed by PMMA:tetracosane (1:3) microcapsule at 23 \({}^{\circ}\)C: (**a**) image of the sample before applying forces, no contact; (**b**) change in the slope, defined as the maximum force that can be applied to the sample ; (**c**) deformation of the sample; (**d**) retraction of the AFM probe until there is no contact between the tip and the sample. Figure 2: Results for PS:tetracosane (1:3): (**a**) Effective Young’s modulus results at 23 \({}^{\circ}\)C; (**b**) Effective Young’s modulus results at 60 \({}^{\circ}\)C.  
The same kind of test was done for the sample composed by PS and tetracosane at 23 \({}^{\circ}\)C and 60 \({}^{\circ}\)C. The results can be observed in Figures 5 and 6, respectively.