Shaping of Nanotubules Formed by Amino Acid Amphiphiles

自组装纳米管是一种非常有趣的胶体系统，因为它们具有明确的结构特征和自下而上的简单形成过程。然而，到目前为止，这些结构的研究很少，其详细的聚集性质仍然知之甚少。我们的项目旨在深入研究由拟肽两亲体（氨基酸两亲体，AAAs）组成的自组装纳米管的形成，并涉及两个主要方向的分子设计和分析。对于这种全面的方法，我们将汇集Technion （D. Danino）和TUB （M. Gradzielski）在自组装及其表征领域的互补专业知识。在第一个方向上，我们将建立纳米管形成趋势与所设计的AAAs的分子结构和化学基序之间的关系。这将涉及两亲体结构的系统变化，其中所需的合成工作将在实验室之间共享。随后，通过直接成像（显微镜）、散射、量热和光谱学方法对聚集体结构进行详细表征，以获得纳米和微米尺度的特征。在这里，直接成像技术（TEM, Technion）和散射技术（TUB）的互补性对于获得详细的结构图像非常重要。从这些结果中可以推导出介观结构与AAAs分子形成之间的关系。为此，在整个研究项目中，将密切和频繁地交流研究成果，以优化联合研究进展。此外，最先进的时间分辨低温透射电镜，SANS和SAXS实验将以互补的方式进行，以允许遵循结构转变的动力学并确定中间结构。这对于理解自组装的驱动力和纳米管形成的途径至关重要。这些知识对于以合理的方式优化纳米管的形成至关重要。在第二个方向上，我们将研究我们定制的AAAs的组装过程在多大程度上可以通过溶液性质（溶剂质量）或添加聚合物表面活性剂作为结构导向剂来控制。这将允许一种简单的方法来获得具有可调谐，良好控制半径和壁厚的定制管，但使用给定类型的aaa。基于这项工作，我们将研究这些纳米管作为形成新材料模板的潜力。这将以一种探索性的方式来完成，以形成银和二氧化钛/二氧化硅棒或管作为有趣的胶体。因此，该项目将对分子自底向上形成自组装纳米管的方法产生基本和全面的理解，并使它们更接近于作为新型胶体系统的应用。

Self-assembled nanotubes are highly interesting colloidal systems due to their well-defined structural characteristics and typically simple formation by a bottom-up process. Yet, so-far, these structures have been studied only scarcely and their detailed aggregation properties are still poorly understood. Our project aims for an in-depth investigation of the formation of self-assembled nanotubes made of peptide-mimetic amphiphiles (amino acid amphiphiles, AAAs), and involves molecular design and analysis in two principal directions. For this comprehensive approach we will bring together the complementary expertise of the Technion (D. Danino) and TUB (M. Gradzielski) group in the fields of self-assembly and its characterisation. In the first direction we will establish relations between the tendency to form nanotubes, and the molecular architecture and chemical motifs of the designed AAAs. This will involve systematic variations of the amphiphile structure, where the synthetic work required will be shared between the labs. Subsequently a detailed characterization of the aggregate structure by direct imaging (microscopy), scattering, calorimetry and spectroscopy methods will be done to access features at the nm- and µm-scale. Here in particular the complementarity of direct imaging (TEM, Technion) and scattering techniques (TUB) is important for obtaining a detailed structural picture. From these results correlations between the mesoscopic structure and the molecular build-up of the AAAs will be derived. For that, as throughout the whole research project, an intense and frequent exchange of research results will be done, in order to optimise the joint research progress.In addition, state-of-the-art time-resolved cryo-TEM, SANS and SAXS experiments will be done in a complementary fashion to allow following the kinetics of the structural transitions and to determine intermediate structures. This is of key importance for the understanding of the driving forces of self-assembly and the pathways involved in nanotube formation. Such knowledge then is the essential for optimising nanotube formation in a rational way. In the second direction we will study to what extent the assembly process of our tailor-made AAAs can be controlled by the solution properties (solvent quality) or the addition of polymer surfactants as structure directing agents. This shall allow for a simple way to access tailor-made tubules with tuneable, well-controlled radii and wall thickness, but employing a given type of AAA.Based on this work we will investigate the potential of these nanotubes as templates for forming novel materials. This will be done in an exploratory way for forming Ag and titania/silica rods or tubules as interesting colloids. Thus, this project will yield a fundamental and comprehensive understanding of the molecular bottom-up approach for forming self-assembled nanotubes, and bringing them closer to applications as novel colloidal systems.