Missikewitsch Annina, Komber Hartmut, Biskup Till, Sommer Michael
Institute for Chemistry, Polymer Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany.
ACS Macro Lett. 2025 Mar 18;14(3):243-249. doi: 10.1021/acsmacrolett.4c00810. Epub 2025 Feb 10.
Toughness engineering of a kinked polyphenylene (PP) is demonstrated by using mechanochromic molecular break points. Varying amounts of thermally stable yet mechanically labile difluorenylsuccinonitrile (DFSN) motifs incorporated into PP allow to largely tune mechanical failure of the specimen. While strain at break values of pristine PP reach up to 300%, an increasing concentration of DFSN break points leads to a strongly decreasing and predictable strain at break. Homolytic bond scission of DFSN and formation of colored DFSN radicals is characterized by UV-vis spectroscopy, which allows us to discern regions of necking and strain hardening during tensile testing. The formation and lifetime of radicals is further probed by EPR spectroscopy, suggesting reversibility of bond scission and thus the possibility to design tough materials with predicted failure and self-healing properties.
通过使用机械变色分子断裂点，展示了扭结聚苯撑（PP）的韧性工程。将不同量的热稳定但机械不稳定的二芴基琥珀腈（DFSN）基团引入PP中，可以在很大程度上调节样品的机械失效。虽然原始PP的断裂应变值可达300%，但随着DFSN断裂点浓度的增加，断裂应变会急剧下降且具有可预测性。通过紫外-可见光谱对DFSN的均裂键断裂和有色DFSN自由基的形成进行了表征，这使我们能够在拉伸试验过程中辨别颈缩和应变硬化区域。通过电子顺磁共振光谱进一步探测自由基的形成和寿命，这表明键断裂具有可逆性，从而有可能设计出具有预测失效和自愈性能的坚韧材料。
