Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Langmuir. 2010 Mar 16;26(6):4288-95. doi: 10.1021/la9033707.
The aggregation behavior of a novel histidine derivative surfactant N-dodecanoyl-L-histidine (DHis) in aqueous solution was investigated. By mixing with cationic/anionic surfactant, an interesting phase transition over time from transparent homogeneous solution to jelly and finally to fibrous floccules was observed with aggregates growth taken place in the systems. Making use of the growing fibrous structures in the DHis/DTEAB and DHis/SDS systems as surface charge tunable dynamic template, we achieved sol-gel replication of silica and titania nanotubes in mild conditions, respectively. The possible mechanism underlying the formation of silica nanotubes was proved to be synergistically self-catalyzed hydrolysis and condensation of silica precursors depositing on the template surface. In particular, by optimizing the sol-gel process, silica nanotubes with tunable sizes in diameter and uniform wall thickness could be obtained in high yield. The large specific surface area and peculiar photoluminescence property of the silica nanomaterials indicated that the synthetic nanotubes were well-defined in both morphology and physical properties. Importantly, this fibrous aggregates could be universally used in opposite charged inorganic precursors to accomplish inorganic oxide nanotubes via sol-gel replication process, which may provide a general route for the construction of one-dimensional nanostructures in aqueous media.
研究了一种新型组氨酸衍生物表面活性剂 N-十二酰基-L-组氨酸（DHis）在水溶液中的聚集行为。通过与阳离子/阴离子表面活性剂混合，观察到体系中发生了有趣的时间依赖性相转变，从透明均相溶液到果冻，最后到纤维絮状物，同时发生了聚集生长。利用 DHis/DTEAB 和 DHis/SDS 体系中生长的纤维状结构作为表面电荷可调动态模板，我们在温和条件下分别实现了二氧化硅和二氧化钛纳米管的溶胶-凝胶复制。证明了形成二氧化硅纳米管的可能机制是协同自催化水解和沉积在模板表面的硅前体的缩合。特别是，通过优化溶胶-凝胶工艺，可以以高产率获得具有可调直径和均匀壁厚的二氧化硅纳米管。硅纳米材料的大比表面积和独特的光致发光性能表明，合成的纳米管在形态和物理性质上都具有很好的定义。重要的是，这种纤维状聚集体可以普遍用于相反电荷的无机前体，通过溶胶-凝胶复制过程完成无机氧化物纳米管的制备，这可能为在水介质中构建一维纳米结构提供一种通用途径。
