Anisotropic self-assembly structures from isotropic building blocks

球形颗粒在所有尺度下形成具有六方堆积的结构。在三维空间中的球体的密集可能堆积是通过在三维空间中堆叠球体的六边形紧密堆积排列形成的。这种直观的结构转换了所有的尺度，从许多原子晶体的晶体结构到球形物体的宏观有序性都可以观察到。球形结构单元在两个维度上的自组装，例如在水体表面的自组装，类似地导致六方密堆积结构。在第一个资助期内，我们已经证明了球形胶体颗粒可以自组装成高度意想不到的结构，例如具有正方形对称性的各向异性链或相。我们已经阐述了这些结构在两亲性添加剂存在下在空气/水界面处形成，前提是满足以下标准。首先，两亲物需要不可逆地吸附到界面;第二，它们必须不相分离，而是与胶体颗粒混合;第三，它们必须是可压缩的。第一个资助期的基本发现是，这些标准导致在界面处颗粒周围形成二维可压缩壳。当压缩在朗缪尔槽上时，这些壳诱导排斥分量到粒子的相互作用势。这种排斥性的组成部分，反过来，导致形成的非常规相的最低能量结构。二十年前，Jagla利用粒子通过方肩排斥势相互作用在理论上预测了这种相，并首次在该项目中实验实现。根据势的形状，理论家预测了各种各样的复杂相，包括不同的准晶结构。在第一个供资期制定的方法提供了实现所需互动潜力的总体战略。然而，双组分混合物阻止了相互作用势的精确工程，这是通过实验获得理论上预测的整个复杂组件所需的。在第二个资助期内，我们将利用现有知识设计具有可控界面相互作用势的单组分核壳颗粒，以实验实现从Jagla型相互作用预测的广泛组装结构。单组分系统的优点是可以通过壳体的尺寸和可压缩性精确地设计相互作用势。通过这些定制的颗粒系统，我们将加深对颗粒界面特性的理解，证明我们可以设计它们的相互作用潜力，并利用这种可能性产生具有前所未有的结构通用性的自组装结构，例如使用胶体光刻的表面纳米结构。

Spherical particles form structures with hexagonal packing at all scales. The densest possible packing of spheres in three dimensions is formed by stacking hexagonally close packed arrangements of spheres in three dimensions. This intuitive structure translates all scales and is observed from the crystal structure of many atomic crystals to the macroscopic ordering of spherical objects. Self-assembly of spherical building blocks in two dimensions, for example at the surface of a water body, similarly results in hexagonally close-packed structures. In the first funding period, we have demonstrated that spherical colloidal particles can self-assemble into highly unexpected structures, for example anisotropic chains or phases with square symmetry. We have elaborated that these structures form at the air/water interface in the presence of amphiphilic additives, provided the following criteria are fulfilled. First, the amphiphiles need to adsorb to the interface irreversibly; second, they must not phase separate but mix with the colloidal particles; and third, they must be compressible. The essential finding of the first funding period was that these criteria lead to the formation of a two-dimensional, compressible shell around the particles at the interface. Upon compression on a Langmuir trough, these shells induce a repulsive component to the interaction potential of the particles. This repulsive component, in turn, causes the formation of the unconventional phases as minimum energy structures. Such phases were theoretically predicted by Jagla using particles interacting via a square-shoulder repulsion potential two decades ago and were for the first time experimentally realized in this project. Depending on the shape of the potential, theoreticians have predicted a wide range of complex phases, including different quasicrystalline structures. The approach developed in the first funding period provides a general strategy to achieve the required interaction potentials. However, the two-component mixtures prevented an accurate engineering of the interaction potential, required to experimentally access the entire range of complex assemblies predicted theoretically. In the second funding period, we will use the established knowledge to design one-component core-shell particles with controllable interfacial interaction potentials to experimentally realize the broad range of assembly structures predicted from Jagla-type interactions. The advantage of a one-component system is the potential to accurately engineer the interaction potential via the size and compressibility of the shell. With these tailored particle systems, we will deepen our understanding of the interfacial properties of particles in general, demonstrate that we can engineer their interaction potential, and use this possibility to generate self-assembled structures with unprecedented structural versatility, for example for surface nanostructuration using colloidal lithography.