Controlled Precipitation of Biominerals using Catanionic Surfactant Self-Assembly Structures

溶变相可以作为溶胶-凝胶法制备介孔陶瓷的模板，并取得了很大的成功。然而，到目前为止，离子晶体还不能用这种方法模板化——可能是由于溶向相的流动性。无盐阳离子表面活性剂体系为解决这一问题提供了一个潜在的解决方案，因为它们的冷冻双层结构在大长度尺度上具有很强的刚性。此外，它们还表现出相当独特的自组装结构。这些相应使用作为模板的CaCO3的结晶在水体制在阳离子相。为此，必须采用在低离子强度下工作的各种结晶技术，以便在纳米尺度上重现阳离子相。特别感兴趣的阳离子相是片层相以及纳米盘和二十面体。如果CaCO3能在层状相内矿化，则会得到一种类似珠层的层状有机-无机杂化材料，具有优异的力学性能。为了实现这一点，必须在Ca2+反离子存在的情况下研究阳离子离子聚集，如果必要的话，必须确定相图。此外，还应探索是否可以将非常小的预成型CaCO3纳米颗粒纳入到阳离子相中，作为随后通过pH循环融合纳米颗粒的材料储存库。如果有可能复制有机模板，则应采用其他相结构，以合成具有各种形态的介观结构CaCO3，这将为通过在复杂流体中复制软超结构来生产介观结构离子晶体奠定基础。这种材料可以找到许多潜在的用途，例如作为高强度材料，介孔存储或传输系统，新的光学或磁性设备等等。

Lyotropic phases could be used with great success as template for the synthesis of mesoporous ceramics via a sol-gel process. However, ion crystals could so far not be templated by such approach - likely as a result of the fluidity of the lyotropic phases. Salt-free catanionic surfactant systems offer a potential solution to this problem as their frozen bilayer structure displays great rigidity over large length scales. Furthermore, they show quite unique self-assembly structures. These phases shall be used as a template for the crystallization of CaCO3 within the water regime in the catanionic phase. For this, various crystallization techniques shall be employed which work at low ionic strength in order to reproduce the catanionic phase on the nm scale. The catanionic phases of particular interest are the lamella phases as well as the nanodisks and icosahedra. If CaCO3 could be mineralized within the lamellar phase, a layered organic-inorganic hybrid material similar to nacre with its superior mechanical properties would result. To achieve this, the catanionic aggregation has to be investigated in presence of the Ca2+ counterions and if necessary, the phase diagrams have to be determined. Also, it shall be explored, if very small pre-formed CaCO3 nanoparticles can be incorporated into the catanionic phases as material reservoir for later nanoparticle fusion via pH cycles. If it is possible to reproduce the organic template, other phase structures shall be employed in order to synthesize mesoscopically structured CaCO3 with various morphologies which will form a basis for the production of mesoscopically structured ionic crystals via the reproduction of soft superstructures in complex fluids. Such materials could find numerous potential uses for example as high strength materials, mesoporous storage or delivery systems, new optical or magnetic devices and so forth.