Owing to their capability of forming extensive hydrogen bondings and the facile introduction of chirality, cyclic dipeptides (CDPs) have gained great attention as scaffolds for functional supramolecules. Surprisingly, introduction of a photopolymerizable diacetylene (DA) moiety to the CDP afforded nanotubular structures with enhanced stability and reversible thermochromism. A series of CDP-containing DAs (CDP-DAs) are prepared by coupling 10,12-pentacosadiynoic acid with CDPs, cyclo(-Gly-Ser) and cis/trans cyclo(-Ser-Ser). Fabrication of CDP-DA self-assemblies in a polar chloroform and methanol solvent mixture affords nanotubes comprising single-wall and multiwall structures. The self-assembly behavior and morphology characteristic are examined by scanning electron microscopy and transmission electron microscopy. Next, X-ray diffraction analysis confirms well-ordered lamellar structures with a perfect agreement with the bilayer formation leading to the tubular structure via lamellar scrolling behavior. Upon UV irradiation, monomeric CDP-DA tubular assemblies result in the blue-colored CDP/polydiacetylene (PDA) nanotubes. Interestingly, CDP/PDA nanotubes exhibit a reversible blue-to-red color change for over 10 consecutive thermal cycles. The CDP-DA/PDA supramolecular system demonstrates potential applications in developing stimulus-responsive functional materials.

中文翻译：

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可逆热致变色环状二肽纳米管

由于其形成广泛的氢键的能力和容易引入的手性，环状二肽（CDP）作为功能性超分子的支架受到了广泛的关注。令人惊讶地，将可光聚合的二乙炔（DA）部分引入CDP提供了具有增强的稳定性和可逆的热致变色性的纳米管结构。通过将10,12-戊二十二碳二烯酸与CDP，环（-Gly-Ser）和顺/反式环（-Ser-Ser）偶联来制备一系列含CDP的DA（CDP-DA）。在极性氯仿和甲醇溶剂混合物中制造CDP-DA自组装体可得到包含单壁和多壁结构的纳米管。通过扫描电子显微镜和透射电子显微镜检查自组装行为和形态特征。下一个，X射线衍射分析证实层状结构与双层结构形成了完美的一致性，并通过层状滚动行为形成了管状结构。在紫外线照射下，单体CDP-DA管状组件会产生蓝色CDP /聚二乙炔（PDA）纳米管。有趣的是，CDP / PDA纳米管在超过10个连续的热循环中呈现出可逆的蓝到红颜色变化。CDP-DA / PDA超分子系统证明了在开发刺激反应性功能材料方面的潜在应用。在超过10个连续的热循环中，CDP / PDA纳米管表现出可逆的蓝到红颜色变化。CDP-DA / PDA超分子系统证明了在开发刺激反应性功能材料方面的潜在应用。在超过10个连续的热循环中，CDP / PDA纳米管表现出可逆的蓝到红颜色变化。CDP-DA / PDA超分子系统展示了在开发刺激反应性功能材料方面的潜在应用。