Liu Jianguo, Chen Feiyu, Zhang Qiaosheng, Xing Xiao, Cui Gan
College of Pipeline and Civil Engineering China University of Petroleum (East China), No. 66, West Changjiang Road, Huangdao District, Qingdao 266580, China.
Changqing Engineering Design Co., Ltd., Xi'an 710000, China.
Polymers (Basel). 2024 Aug 30;16(17):2473. doi: 10.3390/polym16172473.
In this paper, microcapsules with acidic pH stimulus responsiveness were prepared through a one-step in situ polymerization method and a layer-by-layer assembly method. The effects of factors such as chitosan (CS) concentration, polymerization time, polymerization process temperature, and the number of polymerization layers on the performance of microcapsules were explored, and microcapsules with optimal performance were prepared and added to the epoxy coating. The morphology and structure of the microcapsules were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential testing. The thermal stability and sustained release properties of the microcapsules were studied through thermogravimetric analysis and sustained release curve testing. Through scratch experiments, immersion experiments, salt spray experiments, and electrochemical impedance spectroscopy tests, the impact of the added amount of microcapsules on the self-healing performance and anti-corrosion performance of the coating in complex environments was explored. The results show that the optimal preparation process of acidic pH-responsive microcapsules requires that the concentration of chitosan is 2 mg/mL, the polymerization time of the polyelectrolyte layer is 8 h, the heating temperature during the polymerization process is 75 °C, and the number of polyelectrolyte layers is three. The prepared acidic pH-responsive microcapsules have good morphology, pH sensitivity, and thermal stability. The average particle size is approximately 203 μm, the drug loading rate reaches 59.74%, and the encapsulation rate reaches 63.99%. The optimal added amount of the acidic pH-responsive microcapsule coating is 15 wt%. The coating has a dual-trigger mechanism underlying it stimulus response capability and has an obvious stimulus response to acidic pH. It can inhibit corrosion in non-scratch areas, and its anti-corrosion ability is significantly stronger than that of epoxy coatings and ordinary self-healing coatings. The coating has a stronger repair effect and anti-corrosion ability when the environmental pH becomes acidic.
本文通过一步原位聚合法和层层组装法制备了具有酸性pH刺激响应性的微胶囊。探讨了壳聚糖（CS）浓度、聚合时间、聚合过程温度和聚合层数等因素对微胶囊性能的影响，制备了性能最优的微胶囊并将其添加到环氧涂层中。通过扫描电子显微镜、傅里叶变换红外光谱和zeta电位测试对微胶囊的形貌和结构进行了表征。通过热重分析和缓释曲线测试研究了微胶囊的热稳定性和缓释性能。通过划痕实验、浸泡实验、盐雾实验和电化学阻抗谱测试，探讨了微胶囊添加量对涂层在复杂环境下的自修复性能和防腐性能的影响。结果表明，酸性pH响应性微胶囊的最佳制备工艺要求壳聚糖浓度为2 mg/mL，聚电解质层的聚合时间为8 h，聚合过程中的加热温度为75℃，聚电解质层数为三层。所制备的酸性pH响应性微胶囊具有良好的形貌、pH敏感性和热稳定性。平均粒径约为203μm，载药率达到59.74%，包封率达到63.99%。酸性pH响应性微胶囊涂层的最佳添加量为15 wt%。该涂层具有双重触发机制，具有刺激响应能力，对酸性pH有明显的刺激响应。它可以抑制非划痕区域的腐蚀，其防腐能力明显强于环氧涂层和普通自修复涂层。当环境pH值变为酸性时，该涂层具有更强的修复效果和防腐能力。
