Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds
Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds
复制标题
具有可交换共价键的可塑液晶弹性体致动器
DOI：
10.1038/nmat3812
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发表时间：
2014-01-01
期刊：
影响因子：
41.2
通讯作者：
Ji, Yan
中科院分区：
文献类型：
--
作者：
Pei, Zhiqiang;Yang, Yang;Ji, Yan
液晶弹性体（LCE）是一类主动移动的聚合物，具有将外部刺激转化为机械驱动的显着实用潜力（1）。然而，LCE的实际应用是缺乏的，因为可逆致动所需的液晶有序的宏观取向（2，3）在实践中难以实现。在这里，我们表明，LCE的处理瓶颈可以通过引入可交换的链接来代替永久的网络交联来克服，这是以前为vitrimers（4，5）证明的概念。具有可交换链接的液晶弹性体（xLCE）是可模制的，允许容易的加工和对准，并且随后可以通过具有不同应力模式的重塑来改变，从而为实用的xLCE致动器和人造肌肉开辟了道路。令人惊讶的是，代替通过具有可交换连接的非液晶瞬态网络的蠕变的外部应力松弛（6，7），xLCE发展出强液晶对准作为机械松弛的替代机制。
Liquid-crystal elastomers (LCEs) are a class of actively moving polymers with remarkable practical potential for converting external stimuli into mechanical actuation(1). However, real-world applications of LCEs are lacking because macroscopic orientation of liquid-crystal order, which is required for reversible actuations(2,3), is hard to achieve in practice. Here we show that the processing bottleneck of LCEs can be overcome by introducing exchangeable links in place of permanent network crosslinks, a concept previously demonstrated for vitrimers(4,5). Liquid-crystal elastomers with exchangeable links (xLCEs) are mouldable, allow for easy processing and alignment, and can be subsequently altered through remoulding with different stress patterns, thus opening the way to practical xLCE actuators and artificial muscles. Surprisingly, instead of external-stress relaxation through the creep of non-liquid-crystal transient networks with exchangeable links(6,7), xLCEs develop strong liquid-crystal alignment as an alternative mechanism of mechanical relaxation.