Kim Dong-Min, Cho Yu-Jin, Choi Ju-Young, Kim Beom-Jun, Jin Seung-Won, Chung Chan-Moon
Department of Chemistry, Yonsei University, Wonju 26493, Gangwon-do, Korea.
Materials (Basel). 2017 Sep 14;10(9):1079. doi: 10.3390/ma10091079.
Low-temperature self-healing capabilities are essential for self-healing materials exposed to cold environments. Although low-temperature self-healing concepts have been proposed, there has been no report of a microcapsule-type low-temperature self-healing system wherein the healing ability was demonstrated at low temperature. In this work, low-temperature self-healing of a microcapsule-type protective coating was demonstrated. This system employed silanol-terminated polydimethylsiloxane (STP) as a healing agent and dibutyltin dilaurate (DD) as a catalyst. STP underwent a condensation reaction at -20 °C in the presence of DD to give a viscoelastic product. The reaction behavior of STP and the viscoelasticity of the reaction product were investigated. STP and DD were separately microencapsulated by in situ polymerization and interfacial polymerization methods, respectively. The STP- and DD-loaded microcapsules were mixed into a commercial enamel paint, and the resulting formulation was applied to glass slides, steel panels, and mortars to prepare self-healing coatings. When the self-healing coatings were damaged at a low temperature (-20 °C), STP and DD were released from broken microcapsules and filled the damaged area. This process was effectively visualized using a fluorescent dye. The self-healing coatings were scratched and subjected to corrosion tests, electrochemical tests, and saline solution permeability tests. The temperature of the self-healing coatings was maintained at -20 °C before and after scratching and during the tests. We successfully demonstrated that the STP/DD-based coating system has good low-temperature self-healing capability.
低温自愈能力对于暴露在寒冷环境中的自愈材料至关重要。尽管已经提出了低温自愈的概念，但尚未有关于微胶囊型低温自愈系统的报道，即在低温下展现出愈合能力的系统。在这项工作中，展示了微胶囊型保护涂层的低温自愈性能。该系统采用硅烷醇封端的聚二甲基硅氧烷（STP）作为愈合剂，二月桂酸二丁基锡（DD）作为催化剂。在DD存在的情况下，STP在-20°C发生缩合反应，生成粘弹性产物。研究了STP的反应行为以及反应产物的粘弹性。分别通过原位聚合法和界面聚合法对STP和DD进行微胶囊化。将负载STP和DD的微胶囊混入商用瓷漆中，所得配方涂覆在载玻片、钢板和砂浆上，制备自愈涂层。当自愈涂层在低温（-20°C）下受损时，STP和DD从破裂的微胶囊中释放出来，填充受损区域。使用荧光染料有效地观察到了这一过程。对自愈涂层进行划痕处理，并进行腐蚀试验、电化学试验和盐溶液渗透性试验。在划痕前后以及试验过程中，自愈涂层的温度保持在-20°C。我们成功证明了基于STP/DD的涂层系统具有良好的低温自愈能力。
