Colloidal quasicrystals with 12-fold and 18-fold diffraction symmetry
Colloidal quasicrystals with 12-fold and 18-fold diffraction symmetry
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DOI：
10.1073/pnas.1008695108
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发表时间：
2011-02-01
影响因子：
11.1
通讯作者：
Foerster, Stephan
中科院分区：
文献类型：
--
作者：
Fischer, Steffen;Exner, Alexander;Foerster, Stephan
胶束是自然界中最简单的自组装例子。与许多其他胶体一样，它们可以在水溶液中自组装形成有序的周期性结构。到目前为止，这些结构都表现出经典的晶体学对称性。在这里，我们报告说，胶束在溶液中可以自组装成准晶相。我们观察到的相位与12倍和18倍衍射对称性。胶体水基准晶是物理和化学上非常简单的系统。可以容易地制备厘米尺寸的宏观单畴样品。面心立方相和两个准晶相之间的相变可以很容易地跟踪原位的时间分辨衍射实验。准晶胶体溶液的发现大大推进了对准晶的理论理解，对于这些系统，准晶状态的稳定性已经在理论上预测了浓度和温度范围，在那里它们被实验观察到。此外，对于准晶体在先进材料中的应用，这一发现具有特别重要的意义，因为它通过已建立的水基胶体自组装技术开辟了准晶体光子带隙材料的途径。
Micelles are the simplest example of self-assembly found in nature. As many other colloids, they can self-assemble in aqueous solution to form ordered periodic structures. These structures so far all exhibited classical crystallographic symmetries. Here we report that micelles in solution can self-assemble into quasicrystalline phases. We observe phases with 12-fold and 18-fold diffraction symmetry. Colloidal water-based quasicrystals are physically and chemically very simple systems. Macroscopic monodomain samples of centimeter dimension can be easily prepared. Phase transitions between the fcc phase and the two quasicrystalline phases can be easily followed in situ by time-resolved diffraction experiments. The discovery of quasicrystalline colloidal solutions advances the theoretical understanding of quasicrystals considerably, as for these systems the stability of quasicrystalline states has been theoretically predicted for the concentration and temperature range, where they are experimentally observed. Also for the use of quasicrystals in advanced materials this discovery is of particular importance, as it opens the route to quasicrystalline photonic band gap materials via established water-based colloidal self-assembly techniques.