Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Advanced Coatings Research Center of Ministry of Education of China , Fudan University , Shanghai 200433 , China.
Shanghai Institute of Spacecraft Equipment , Shanghai 200240 , China.
ACS Appl Mater Interfaces. 2019 Sep 11;11(36):33314-33322. doi: 10.1021/acsami.9b10737. Epub 2019 Aug 26.
Advanced polymer composite coatings in the spacecraft are threatened by harsh space environment factors, such as strong UV radiation, atomic oxygen, thermal cycles, space debris, etc. Their service life can be drastically shortened by the unavoidable formation of cracks caused by these factors (especially strong and abundant UV radiation) during long-term flight. Herein, a UV-responsive microcapsule-based coating is developed for in-orbit damage repairing. UV-responsive microcapsules of which the inner polymeric shell can be degraded rapidly by the outer pure TiO shell under UV radiation are produced by UV-initiated polymerization of Pickering emulsions and subsequently embedded into silicon resin matrices. When damaged, some microcapsules will be ruptured under the stimulus of external force, afterward the unbroken ones around the scratched areas will be degraded by UV radiation, as a result, encapsulated healing agents can be released and finally repair cracks. In this system, UV-responsive microcapsules can release more agents more effectively due to the dual release mode, compared with the traditional crack-repairing system. Moreover, the damage of UV radiation in space can be transferred into the favorable ones, which makes it have a potential application in aerospace coatings.
航天器中的先进聚合物复合涂层受到恶劣空间环境因素的威胁，如强紫外线辐射、原子氧、热循环、空间碎片等。在长期飞行过程中，这些因素（尤其是强烈和丰富的紫外线辐射）不可避免地会导致裂纹的形成，从而大大缩短其使用寿命。在此，开发了一种基于紫外光响应微胶囊的涂层，用于轨道损伤修复。通过 Pickering 乳液的紫外光引发聚合反应制备了外层为纯 TiO 壳、内层聚合物壳可在紫外光辐射下迅速降解的紫外光响应微胶囊，随后将其嵌入硅树脂基质中。当受到损伤时，一些微胶囊会在外部力的刺激下破裂，随后划伤区域周围未破裂的微胶囊会被紫外光降解，从而释放出封装的愈合剂并最终修复裂纹。在该体系中，由于双重释放模式，紫外光响应微胶囊可以更有效地释放更多的试剂，与传统的裂纹修复体系相比。此外，空间中紫外线辐射的损伤可以转化为有利的损伤，这使得它在航空航天涂料中有潜在的应用。
