Designing Smart Microcapsules with Natural Polyelectrolytes to Improve Self-Healing Performance for Water-Based Polyurethane Coatings
Designing Smart Microcapsules with Natural Polyelectrolytes to Improve Self-Healing Performance for Water-Based Polyurethane Coatings
复制标题
用天然聚电解质设计智能微胶囊以提高水性聚氨酯涂料的自修复性能
DOI：
10.1021/acsami.2c18339
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发表时间：
2022-11-15
影响因子：
9.5
通讯作者：
Li, Ying
中科院分区：
文献类型：
--
作者：
Li, Bowen;Njuko, Demian;Li, Ying
采用微胶囊的活性防腐有机涂料近年来受到了广泛的关注，因为它们被证明能够有效地减少金属腐蚀并提供持久的保护性能。本文以2-巯基苯并噻唑(2-MBT)为缓蚀剂，埃洛石粘土纳米管(HNTs)为缓蚀剂载体，以天然聚电解质epsilon-聚-L-赖氨酸(epsilon-pll)和海藻酸钠(SA)为逐层包覆聚电解质，以水性和碱性pH响应型智能MC为缓蚀剂，设计了一种新型环保型活性防腐体系。盐雾试验和电化学测试表明，在AA2024表面形成了一层释放的2MBT的吸附层，在浸泡6d内缓蚀率可达90%以上，具有良好的自愈合性能。UV-Vis分光光度结果进一步表明，2-MBT的释放是一个对水和碱性pH值敏感的三阶段长时间过程，而向外释放速率同时受2-MBT的溶解度和SA层的调节。制造的MC不仅提供了良好的自愈性能，而且为未来基于LBL技术的高级MC的按需设计提供了光明。
Active anticorrosive organic coatings adopting microcapsules (MCs) have lately attracted extensive attention as they were proven to be effective to minimize metal corrosions and offer a long-lasting protection performance. Herein, a novel environmental-friendly active corrosion protection system was designed for aluminum alloy 2024 (AA2024) based on water-based polyurethane coatings with the addition of water and alkaline pH responsive smart MCs, which is fabricated by utilizing 2mercaptobenzothiazole (2-MBT) as an inhibitor, halloysite clay nanotubes (HNTs) as an inhibitor carrier, and the natural polyelectrolytes epsilon-poly-L-lysine (epsilon-PLL) and sodium alginate (SA) as layer-by-layer (LBL) encapsulation polyelectrolytes. Salt spray tests and electrochemical measurements prove that the scratched coatings with embedded MCs possess an excellent self-healing performance by forming an adsorption layer of released 2MBT on the AA2024 surface, thereby providing over 90% inhibition efficiency within 6 days' immersion. The UV-vis spectrophotometer results further showed that the release of 2-MBT is a three-stage long-term process sensitive to water and alkaline pH value, while the outward release rate is both regulated by the solubility of 2-MBT and the SA layer. The fabricated MCs not only offer a great promise to provide an excellent self-healing performance but also shed light on the future design of advanced MCs on demand based on the LBL technique.