Sakai Hio, Sumi Toshikazu, Aoki Daisuke, Goseki Raita, Otsuka Hideyuki
Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
ACS Macro Lett. 2018 Nov 20;7(11):1359-1363. doi: 10.1021/acsmacrolett.8b00755. Epub 2018 Oct 29.
Mechanochromism, a color change induced by mechanical force, has attracted much attention in materials science, as it can be used to create stress- and damage-detecting sensors. In particular, radical-type mechanochromic molecules (mechanochromophores), which produce colored radicals upon exposure to mechanical force, enable the qualitative visualization of mechanical stress and the quantitative evaluation of the generated radical species by electron paramagnetic resonance spectroscopy. However, the sensitivity of radical-type mechanochromophores to thermal stimuli limits their range of applications. Herein, we report the radical-type mechanochromophore difluorenylsuccinonitrile (DFSN), which can be used to synthesize mechanochromic polymers via living radical polymerization techniques, as its central carbon-carbon bond exhibits high thermal stability. The obtained DFSN-centered polymers show mechanochromism and desirably high thermal resistance.
机械变色现象，即由机械力引起的颜色变化，在材料科学领域备受关注，因为它可用于制造应力和损伤检测传感器。特别是自由基型机械变色分子（机械发色团），在受到机械力作用时会产生有色自由基，能够通过电子顺磁共振光谱对机械应力进行定性可视化，并对生成的自由基种类进行定量评估。然而，自由基型机械发色团对热刺激的敏感性限制了它们的应用范围。在此，我们报道了自由基型机械发色团二芴基琥珀腈（DFSN），由于其中心碳 - 碳键具有高的热稳定性，可通过活性自由基聚合技术用于合成机械变色聚合物。所得到的以DFSN为中心的聚合物表现出机械变色现象且具有理想的高耐热性。
