## Materials and Methods
### Testing and Characterization
Grade 0 indicated that the paint film surface had not fallen off. Grade 1 indicated that about 5% of the paint film surface had fallen off. Grade 2 indicated that the paint film surface has fallen off by 15%. Grade 3 indicated that 35% of the paint film had fallen off. Grade 4 indicated that the paint film surface had fallen off by about 55%. Grade 5 indicated that the paint film surface had fallen off seriously, exceeding 60%. The impact resistance of the paint film was tested by QCJ impactor tester (Tianjin Shumnuo Instrument Technology Co., Ltd., Tianjin, China) according to GB/T 1732-1993 [28]. The 1.0 kg weight hammer was fixed on a certain height, and the hammer was allowed to drop freely on the impact test sheet, and whether there were cracks and peeling phenomenon of the paint film was observed. The maximum height of the paint film without rupture was the impact strength. The AG-IC100 KN precision universal mechanical testing machine (Dongguan Seput Testing Equipment Co., Ltd., Dongguan, China) was used to measure the elongation at break of the paint film. The paint film was coated on the glass substrate and peeled off with a knife after being dried. The two ends of the paint film were fixed with a clamp, and the paint film was stretched at a speed of 0.12 mm/min and broken under a certain longitudinal load. L\({}_{0}\) represented the initial value of the distance between the clampers, L\({}_{a}\) represented the distance of the clampers when it is broken. The elongation at break (e) of the paint film can be calculated by Equation (2)  
\[\mathrm{e}=(\mathrm{L}_{a}-\mathrm{L}_{0})/\mathrm{L}_{0}\times 100\% \tag{2}\]  
The liquid resistance of the paint film was tested by 15.0% NaCl, red ink, 70.0% medical ethanol, white cat detergent which contained 25.0% fatty alcohol ethylene oxide and 75.0% water. The filter paper was soaked in the test solution, taken out with tweezers and placed on the sample. Five layers of paper were placed on each test area and covered with glass. After 24 h, the circular paper was peeled off, then the residual liquid was sucked up with filter paper, and the color difference and the gloss of the paint film surface were observed [29]. When American lime is heated above 160 \({}^{\circ}\)C, the discoloration is serious, and it is easy to deform and crack at high temperature due to the wet expansion and dry shrinkage. Therefore, the maximum temperature of 160 \({}^{\circ}\)C is selected as the limit value. Aging and stability tests were carried out in the oven at temperatures of 120 and 160 \({}^{\circ}\)C, and a ZN ultraviolet weather resistance test chamber (Shenzhen Changxu Machinery Equipment Co., Ltd., Shenzhen, China). Then, the color difference and gloss of the paint film were tested. The aging time of oven was set as 40 h, and that of the UV weathering test chamber was 200 h. The damage of the paint films with microcapsules and without microcapsules in different aging environments was compared. The standard deviation analysis method is used for statistical analysis of data. In short, standard deviation is a measurement concept of the degree to which a set of values are dispersed from the average value. A large standard deviation means that there is a big difference between most values and their average values; a small standard deviation means that these values are closer to the average. \(N\) is the number of the total number, \(\chi_{i}\) is the \(i\)-th data and \(\mu\) is the average value. The standard deviation (\(\sigma\)) was calculated by Equation (3)  
\[\sigma=\sqrt{\frac{1}{N}\sum_{i=1}^{N}(\chi_{i}-\mu)^{2}} \tag{3}\]  
All the tests were repeated four times, and the error was within 5.0%.