Mechanics of light-activated self-healing polymer networks
Mechanics of light-activated self-healing polymer networks
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DOI：
10.1016/j.jmps.2018.11.019
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发表时间：
2019-03
影响因子：
5.3
通讯作者：
Kunhao Yu;A. Xin;Qiming Wang
中科院分区：
文献类型：
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作者：
Kunhao Yu;A. Xin;Qiming Wang
可光学修复的聚合物代表了一种有趣的刺激响应型自我修复材料，因为修复过程可以按需远程控制。光激活界面自愈合过程的基本机制在理论上尚不清楚。在这里，我们提出了一个理论框架来理解具有光响应光团的软聚合物的光激活界面自修复。我们认为，光通过材料基质的传播触发了自由基的产生，从而促进了界面的自我修复过程。自愈过程被认为是一种耦合行为，即聚合物链在界面上扩散，并在自由基的帮助下重新形成动态键。我们从理论上将光性质与聚合物的界面自愈强度联系起来。我们预测，聚合物的界面自愈合强度随着光照时间的延长而增加，直到达到平台期。我们从理论上解释了光强度、光波长和光引发剂浓度对自愈性能的影响。然后，我们将该理论应用于两种类型的软聚合物，分别具有无机和有机光团。实验测量的原始试件和自愈试件的应力-应变行为可以用该理论一致地解释。实验测得的愈合强度与愈合时间的关系也与理论结果吻合较好。
Optically healable polymers represent an interesting stimuli-responsive self-healing material as the healing process can be controlled on-demand and remotely. The fundamental mechanism of the light-activated interfacial self-healing process has not been theoretically understood. Here, we present a theoretical framework to understand the light-activated interfacial self-healing of soft polymers with light-responsive photophores. We consider that the light propagation through the material matrix triggers the production of free radicals that facilitate the interfacial self-healing process. The self-healing process is considered as a coupled behavior that polymer chains diffuse across the interface and re-form the dynamic bonds assisted by the free radicals. We theoretically relate the light property to the interfacial self-healing strength of the polymers. We predict that the interfacial self-healing strength of the polymer increases with the light illumination time until reaching a plateau. We theoretically explain the effects of the light intensity, light wavelength, and photoinitiator concentration on the self-healing performance. We then apply the theory to two types of soft polymers with inorganic and organic photophores, respectively. The experimentally measured stress–strain behaviors of the original and self-healed samples can be consistently explained by the theory. The experimentally measured relationships between the healing strength and the healing time also agree well with the theoretical results.