White S R, Sottos N R, Geubelle P H, Moore J S, Kessler M R, Sriram S R, Brown E N, Viswanathan S
Department of Aeronautical and Astronautical Engineering, University of Illinois at Urbana-Champaign, Urbana 61801, USA.
Nature. 2001 Feb 15;409(6822):794-7. doi: 10.1038/35057232.
Structural polymers are susceptible to damage in the form of cracks, which form deep within the structure where detection is difficult and repair is almost impossible. Cracking leads to mechanical degradation of fibre-reinforced polymer composites; in microelectronic polymeric components it can also lead to electrical failure. Microcracking induced by thermal and mechanical fatigue is also a long-standing problem in polymer adhesives. Regardless of the application, once cracks have formed within polymeric materials, the integrity of the structure is significantly compromised. Experiments exploring the concept of self-repair have been previously reported, but the only successful crack-healing methods that have been reported so far require some form of manual intervention. Here we report a structural polymeric material with the ability to autonomically heal cracks. The material incorporates a microencapsulated healing agent that is released upon crack intrusion. Polymerization of the healing agent is then triggered by contact with an embedded catalyst, bonding the crack faces. Our fracture experiments yield as much as 75% recovery in toughness, and we expect that our approach will be applicable to other brittle materials systems (including ceramics and glasses).
结构聚合物容易受到裂缝形式的损伤，这些裂缝在结构内部深处形成，难以检测且几乎无法修复。裂缝会导致纤维增强聚合物复合材料的机械性能下降；在微电子聚合物部件中，它还可能导致电气故障。由热疲劳和机械疲劳引起的微裂纹也是聚合物粘合剂中长期存在的问题。无论应用场景如何，一旦聚合物材料内部形成裂缝，结构的完整性就会受到严重损害。此前已有探索自我修复概念的实验报道，但迄今为止报道的唯一成功的裂缝修复方法都需要某种形式的人工干预。在此，我们报告一种具有自主修复裂缝能力的结构聚合物材料。该材料包含一种微胶囊化的愈合剂，在裂缝侵入时释放。然后，愈合剂与嵌入的催化剂接触引发聚合反应，使裂缝面结合在一起。我们的断裂实验表明，韧性恢复高达75%，我们预计我们的方法将适用于其他脆性材料系统（包括陶瓷和玻璃）。
