Title: A Reactive Azobenzene Liquid-Crystalline Block Copolymer as a Promising Material for Practical Application of Light-driven Soft Actuators

Author: Jiu-an Lv, Wei Wang, Wei Wu, Yanlei Yu*

Journal: J. Mater. Chem. C, 2015, 3(26), 6621-6626

Abstract:

Cross-linked liquid-crystalline polymers containing azobenzene have been drawing the great research interests of the scientists due to their significant values in design of light-driven soft actuators. However, poor processabilities due to the chemical cross-linking severely prevent their practical applications. Here, we designed and synthesized a novel reactive block copolymer PEO-b-PAZO bearing N-hydroxysuccinimide carboxylate substituted azobenzene groups. This copolymer is compatible with the traditional polymer processing methodology including melt and solution processing methods, providing a facile way to prepare the photoresponsive films and fibers, and enabling post-crosslinking after processing through a mild reaction between N-hydroxysuccinimide carboxylate substituents and a difunctional amine. Most importantly, the prepared fibers and films showed reversible photodeformation regulated by alternating irradiation of UV and visible light (365 nm/470 nm). We envision that this novel liquid crystalline polymer will open up new possibilities for low-cost fabrication of high performance photo-driven actuators on a large scale.

论文链接：https://pubs.rsc.org/en/content/articlelanding/2015/TC/C5TC00595G#!divAbstract

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该研究成功地合成了一种新型反应性嵌段共聚物PEO-b-PAZO，并通过将PEO-b-PAZO与1,6-己二胺在室温下进行温和的化学交联反应，制备了单畴交联液晶聚合物（CLCP）纤维和多畴CLCP膜。在紫外和可见光的交替照射下，CLCP纤维和薄膜均表现出可逆的光诱导弯曲和回复行为。单畴CLCP纤维沿纤维轴线即液晶基元取向方向向光源弯曲，因此，当我们改变入射紫外光的照射方向时，纤维能够向任何方向弯曲。另一方面，多畴CLCP薄膜在线性偏振光照射下发生定向弯曲行为。该反应性嵌段共聚物（PEO-b-PAZO）具有优良的加工性能，可制备具有良好光机械性能和无形状限制的独立式CLCP。PEO-b-PAZO无论是熔融处理还是溶液处理，都有利于实现CLCP作为光驱动执行器的大规模实际应用。