基于动态共价交联网络自修复涂层的研究进展

Research progress of self-healing coatings based on dynamic covalent crosslinking

  • 摘要: 涂层是材料抵御外界应力损伤的重要屏障,且随着科技的发展,智能涂层可在原先的基础上赋予涂层荧光、抗菌、检测、传感等先进功能。然而,此类涂层在使用过程中不可避免会受到机械破坏(如擦痕、刮伤等)及与内部各组分应力不匹配引发的宏观或者微观损伤,导致裂纹甚至开裂,结构损伤会引起功能的减弱甚至消失。因此,对涂层结构稳定性和功能持续性提出了更高要求。基于动态共价交联网络的自修复涂层是以动态共价键可逆反应为基础,在一定的外界刺激下建立原料分子与产物分子之间的热力学平衡,通过动态网络“重组”实现对涂层自修复。动态网络活化能的大小不仅能直接反映修复难易程度(反应速率),也能间接反映材料的力学表现。因此,本文将从化学热/动力学角度出发,分析自修复网络构筑与反应活化能之间的关系,并进一步概述基于动态共价交联网络的自修复涂层在传统涂料(层)、智能传感、光学变色、生物医药领域的应用。最后对动态共价自修复涂层目前存在的局限和未来的发展进行展望。

     

    Abstract: It is an important barrier for coating materials to resist external stress damage, with the development of science and technology, intelligent coating can endow the original coating with advanced functions such as fluorescence, antibacterial, detection and sensing, etc. However, it will inevitably suffer from mechanical damage (such as scratches, scratches, etc.) and macroscopic or microscopic damage caused by stress mismatch with internal components, which will lead to cracks or even cracks, and structural damage will lead to functional weakening or even disappearance. Therefore, higher requirements were put forward for the structural stability and functional continuity of the coating. The self-healing coatings, based on dynamic covalent cross-linking network, can establish a thermodynamic equilibrium between the raw materials molecules and product molecules, and obtain the self-healing capacity via the recombination of dynamic network. The activation energy value of dynamic network not only directly reflects ease of healing reaction (i.e., reaction rate), but also affects the mechanical performance of the resultant materials. In this paper, we discuss and clarify the relationship between the construction of self-healing network and activation energy of reaction according to the chemical thermodynamics, subsequently, we comment the applications of the self-healing coatings with dynamic covalent cross-linking network in the fields of traditional coatings, intelligent sensor, photochromic, biological medicine. Finally, we prospect the developed bottleneck and perspective of the dynamic covalent self-healing coatings.

     

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