Pouget Emilie, Dujardin Erik, Cavalier Annie, Moreac Alain, Valéry Céline, Marchi-Artzner Valérie, Weiss Thomas, Renault Anne, Paternostre Maité, Artzner Franck
Groupe Matière Condensée et Matériaux, UMR 6626 CNRS et Université Rennes 1, 263 Avenue du général Leclerc, 35042 Rennes Cedex, France.
Nat Mater. 2007 Jun;6(6):434-9. doi: 10.1038/nmat1912. Epub 2007 May 21.
Diatoms, shells, bones and teeth are exquisite examples of well-defined structures, arranged from nanometre to macroscopic length scale, produced by natural biomineralization using organic templates to control the growth of the inorganic phase. Although strategies mimicking Nature have partially succeeded in synthesizing human-designed bio-inorganic composite materials, our limited understanding of fundamental mechanisms has so far kept the level of hierarchical complexity found in biological organisms out of the chemists' reach. In this letter, we report on the synthesis of unprecedented double-walled silica nanotubes with monodisperse diameters that self-organize into highly ordered centimetre-sized fibres. A unique synergistic growth mechanism is elucidated by the combination of light and electron microscopy, synchrotron X-ray diffuse scattering and Raman spectroscopy. Following this growth mechanism, macroscopic bundles of nanotubules result from the kinetic cross-coupling of two molecular processes: a dynamical supramolecular self-assembly and a stabilizing silica mineralization. The feedback actions between the template growth and the inorganic deposition are driven by a mutual electrostatic neutralization. This 'dynamical template' concept can be further generalized as a rational preparation scheme for materials with well-defined multiscale architectures and also as a fundamental mechanism for growth processes in biological systems.
硅藻、贝壳、骨骼和牙齿是结构清晰的精妙实例，它们由纳米级到宏观长度尺度排列而成，是通过天然生物矿化作用利用有机模板控制无机相生长而产生的。尽管模仿自然的策略在合成人工设计的生物无机复合材料方面取得了部分成功，但目前我们对基本机制的理解有限，使得生物有机体中发现的层次复杂性水平仍超出化学家的掌控范围。在这封信中，我们报道了合成出前所未有的具有单分散直径的双壁二氧化硅纳米管，这些纳米管自组装成高度有序的厘米级纤维。通过光学显微镜和电子显微镜、同步加速器X射线漫散射以及拉曼光谱的结合，阐明了一种独特的协同生长机制。遵循这种生长机制，宏观的纳米管束是由两个分子过程的动力学交叉耦合产生的：动态超分子自组装和稳定的二氧化硅矿化。模板生长与无机沉积之间的反馈作用是由相互的静电中和驱动的。这种“动态模板”概念可以进一步推广，作为一种制备具有明确多尺度结构材料的合理方案，也作为生物系统中生长过程的一种基本机制。
