Enabling Room-Temperature Mechanochromic Activation in a Glassy Polymer: Synthesis and Characterization of Spiropyran Polycarbonate
Enabling Room-Temperature Mechanochromic Activation in a Glassy Polymer: Synthesis and Characterization of Spiropyran Polycarbonate
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DOI：
10.1021/jacs.9b04229
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发表时间：
2019-06-26
影响因子：
15
通讯作者：
Silberstein, Meredith N.
中科院分区：
文献类型：
--
作者：
Vidaysky, Yuval;Yang, Steven J.;Silberstein, Meredith N.
通过力响应分子（即机械基团）实现的机械致色功能在聚合物的空间局部损伤预警方面具有很大的潜力。然而，在结构塑料中，损伤预警是最关键的，这种方法收效甚微，因为脆性破坏通常先于可检测到的颜色变化。本文报道了螺吡喃在高T-g双酚A聚碳酸酯中的室温机械变色活化。以双羟基螺吡喃为共聚单体，在保留聚碳酸酯优异的热机械性能的同时，引入了机械变色功能。对应力、变形和时间变化的力学变色行为进行了全面评估，为加载历史如何控制聚合物链中的应力积累提供了新的见解。此外，利用机械致色层压板证明了一种将机械致色功能整合到结构中而不分散昂贵的机械基团的新方法。结构聚合物的室温机械致色活化结合新的高效制备和加工方法，使我们离机械致色智能材料的应用更近了一步。
Mechanochromic functionality realized through force-responsive molecules (i.e., mechanophores) has great potential for spatially localized damage warning in polymers. However, in structural plastics, for which damage warning is most critical, this approach has had minimal success because brittle failure typically precedes detectable color change. Herein, we report on the room-temperature mechanochromic activation of spiropyran in high T-g bisphenol A polycarbonate. The mechanochromic functionality was introduced by polymerization of dihydroxyspiropyran as a comonomer while retaining the excellent thermomechanical properties of the polycarbonate. The mechanochromic behavior is thoroughly evaluated in response to changes in stress, deformation, and time, providing new insights regarding how loading history controls stress accumulation in polymer chains. In addition, a new method to incorporate mechanochromic functionality in structures without dispersing costly mechanophores in the bulk is demonstrated by using a mechanochromic laminate. The room-temperature mechanochromic activation in a structural polymer combined with the new and efficient preparation and processing methods bring us closer to the application of mechanochromic smart materials.