吉林大学陈于蓝团队报道了罗丹明-螺吡喃共轭物在多种刺激下增强聚合物的可调机械变色性。相关研究成果于2024年7月5日发表在《德国应用化学》。

通过聚合物中的力响应机械基团实现的机械变色功能，在损伤传感和信息存储方面具有巨大潜力。具有识别多种刺激以实现可调变色特性的机械基团，因其多功能传感能力和颜色可编程性而备受追捧。然而，大多数机械基团都是基于灵敏度有限的单组分发色团，或者需要额外的制造技术来实现多模式色度。

该文中，研究人员报道了一种新的多功能机械载体，它能够在聚合物中生动地检测和调节机械变色。这种协同光学耦合依赖于战略性地融合罗丹明和螺吡喃（Rh SP），并将聚合物链束缚在两个亚基上。根据力和光控弛豫过程的变化，全面评估了Rh-SP连接聚合物在超声处理和压缩下的机械变色行为。

识别出两个亚基在力作用下的非连续开环，赋予了高对比度的机械变色性。光诱导的两个亚基的微分闭环反应，以及SP部分的酸性色度，被用于设计具有可编程和宽光谱颜色的弹性体。

该工作为高度可感知和可调节的机械变色功能提供了一种有效的策略，也为π-融合机械载体的断裂机制，以及刺激历史如何控制聚合物中的应力积累提供了新的见解。

附：英文原文

Title: A Rhodamine-Spiropyran Conjugate Empowering Tunable Mechanochromism in Polymers under Multiple Stimuli

Author: Ze-Ying Sun, Yiran Li, Mengjiao Wu, Weiye He, Yuan Yuan, Yi Cao, Yulan Chen

Issue&Volume: 2024-07-05

Abstract: Mechanochromic functionality realized via the force-responsive mechanophores in polymers has great potential for damage sensing and information storage. Mechanophores with the ability to recognize multiple stimuli for tunable chromic characteristics are highly sought after for versatile sensing ability and color programmability. Nevertheless, the majority of mechanophores are based on single-component chromophores with limited sensitivity, or require additional fabrication technology for multi-modal chromism. Here, we report a novel multifunctional mechanophore capable of vividly detectable and tunable mechanochromism in polymers. This synergistic optical coupling relies on strategically fusing rhodamine and spiropyran (Rh-SP), and tethering polymer chains on both subunits. The mechanochromic behaviors of the Rh-SP-linked polymers under sonication and compression are thoroughly evaluated in response to changes in force and the light-controlled relaxation process. Non-sequential ring-opening of the two subunits under force is identified, endowing high-contrast mechanochromism. Light-induced differential ring-closing reactions of the two subunits, together with the acidichromism of the SP moiety, are employed to engineer elastomers with programmable and wide-spectrum colors. Our work presents an effective strategy for highly appreciable and regulable mechanochromic functionality, and also provides new insights into the rupture mechanisms of π-fused mechanophores, as well as how the stimuli history controls stress accumulation in polymers.

DOI: 10.1002/anie.202411629

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202411629