基于质子转移的扭曲共轭酸碱两性分子类力致变色材料的研发

Stimuli-responsive intelligent materials with tunable absorption or fluorescence have attracted much attention nowadays due to their promising applications in sensors, anti-counterfeiting and optical recording devices. However, compared with photo-, thermo-, and electrochromic materials, the mechanochromic materials (MMs), which show color changes upon grinding, compressing, shearing, and other external mechanical forces, are still in its infancy. So far, most MMs works on conformational and (or) aggregation state change upon external mechanical forces. The design strategies and in-depth understanding of their mechanochromic mechanisms are still inadequate. We propose to extend the effect of external force on molecular conformation to molecular reactivity to explore reaction-dependent reversible MMs. Based on the concept, a series of twisted and conjugated amphoteric molecules (TCAM) are designed. We have proposed and proved that inter/intra molecular proton transfer will be induced after the molecules are pressed to more planar conformations and it results in a dramatic absorption and fluoresence response. In this proposal, we will systematically investigate the mechanochromic mechanisms, explore more mechanochromic TCAM candidates, develop a theory on design of such materials and explore the applications of these TCAM on hydrostatic pressure-sensor, ink-free writing and anti-counterfeiting. This proposal is very creative, original, and is important for both fundamental and application research.

刺激响应变色智能材料因其在传感、防伪、光学存储等方面的应用而备受关注。力致变色材料是指在研磨、挤压、剪切等外力的作用下发生颜色变化的一类材料。到目前为止，力致变色材料的工作原理和设计策略还主要集中在用外力来调控光功能分子的构象及聚集状态。我们提出将外力对分子构象的影响扩展到对分子化学反应活性的影响，开发基于外力作用下可逆化学反应的力致变色材料。基于此理念，设计了一系列扭曲共轭酸碱两性分子，证实了在外力作用下，扭曲共轭酸碱两性分子发生了分子间/内的质子转移，并伴随明显的表观颜色及荧光响应。本项目拟系统地研究此类材料力致变色的真正机理，开发出颜色对比鲜明、可调性好、多信号输出的力致变色材料，形成可以指导设计合成的理论，并开发此类材料在静水压传感、无墨书写和防伪上的实际应用。本项目具有原始创新性，有望开发出高性能的力致变色材料及形成设计理论。