Polymerization of Supramolecular Assemblies for Template-to-Template Synthesis (T2T)

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Supramolecular self-assembly is a powerful tool in the control of nanometer structure formation for new materials functionalities. In macromolecular chemistry supramolecular organization has been studied intensively. On the other hand formation of macromolecular nanostructures from supramolecularly pre-organized monomers represents a less developed template approach. It has been demonstrated that nanoobjects, such as spheres and rods, can result from crosslinking of bilayer vesicles and by polymerization of monomers in mesophases such as an inverted hexagonal phases. So far, however, examples where it has been possible to control the size of the molecular objects, are rare. Here we investigate the complexes of wedge-shaped sulfonic acids with polymers containing complementary basic groups. We have demonstrated that these complexes assemble in dilute solution to single spheres as well as cylindrical superstructure, and lamellar or hexagonal columnar phase in bulk depending on the degree of neutralization. In the supramolecular cylinders, individual polymer chains are enclosed by the wedgeshaped molecules and the length of the cylinders is defined by the contour length of the corresponding polymer backbone similar like in the case of tobacco mosaic virus where a protein capsid is assembled around the RNA. The aim of this research project is to use this self-organization mechanism to prepare functional nanoobjects with defined dimensions and to accomplish a template-to-template synthesis, enabling replication of the molecular weight. For this purpose, polymerizable groups will be introduced at the thicker end of the wedge-shaped molecules that is oriented towards the outside of the assemblies. Polymerization in the assembled state allows to stabilize the structure. In this case self-assembly involves complexation of wedge molecules to a linear macromolecule, cylinders can be formed whose length is controlled by the core macromolecule. After polymerization of the coat forming molecules, a true supramolecular macromolecule whose size is templated from the core molecule and which itself can form a functional pore that takes up monomers. This way it can serve as a template to control the length of the polymer in its core. Chirality will be introduced into either the side groups or the polymer backbone, which will hopefully result in the formation of pores with chiral arrangement of functional groups. Consequently, polymers with defined tacticity can be synthesized using such templates. One key question here is whether it will be possible to confine the polymerization to intra-complex linkages (within the single rods), i.e. to avoid intercomplex cross-linking. Another key question concerns the formation of the supramolecular complex with suitable monomers like vinylpyridine that can undergo spontaneous polymerization in contact with the strong acids.