Xie Hui, Deng Xiao-Ying, Cheng Chuan-Ying, Yang Ke-Ke, Wang Yu-Zhong
Center for Degradable and Flame-Retardant Polymeric Materials, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), State Key Laboratory of Polymer Materials Engineering, College of Chemistry, Sichuan University, Chengdu, 610064, China.
Macromol Rapid Commun. 2017 Feb;38(4). doi: 10.1002/marc.201600664. Epub 2017 Jan 3.
Multistimuli-responsive shape-memory polymers are highly desirable in various applications, and numerous modes have been developed in recent years. However, most of them need to reprogram before they are ready to respond to another stimulus while one is triggered. Here, a new strategy is developed to achieve dual-stimuli-responsive triple-shape memory with non-overlapping effect in one programming cycle. Here, a series of poly(l-lactide)-poly(tetramethylene oxide) glycol copolymers (PLA-PTMEG-A) is prepared by selected dangling photoresponsive anthracene moieties on the crystalline PTMEG backbone. The architectures of the copolymers are well-controlled in order to keep a good balance between the crystallinity of the soft segment and the mobility of the anthracene moieties. Thus, PLA-PTMEG-A's can respond to heat and light with non-overlapping effect. The thermally-induced shape-memory effect (TSME) is realized by the crystallization-melting transition of PTMEG soft segments, while the light-induced shape-memory effect (LSME) is achieved by the reversible photodimerization of anthracene groups. In view of the non-overlapping effect of TSME and LSME in the copolymers, a triple-shape-memory effect triggered by dual-stimuli is realized in one programming and recovery cycle.
多刺激响应形状记忆聚合物在各种应用中非常理想，近年来已经开发出多种模式。然而，它们中的大多数在一种刺激被触发时，需要重新编程才能对另一种刺激做出响应。在此，开发了一种新策略，以在一个编程周期内实现具有非重叠效应的双刺激响应三重形状记忆。在此，通过在结晶的聚四亚甲基醚二醇（PTMEG）主链上选择悬挂的光响应性蒽基团，制备了一系列聚（L-丙交酯）-聚四亚甲基醚二醇共聚物（PLA-PTMEG-A）。对共聚物的结构进行了良好控制，以便在软段的结晶度和蒽基团的流动性之间保持良好平衡。因此，PLA-PTMEG-A能够以非重叠效应响应热和光。热诱导形状记忆效应（TSME）通过PTMEG软段的结晶-熔融转变实现，而光诱导形状记忆效应（LSME）通过蒽基团的可逆光二聚化实现。鉴于共聚物中TSME和LSME的非重叠效应，在一个编程和恢复周期内实现了由双刺激触发的三重形状记忆效应。
