Lateral interactions at functional monolayers

Molecular nanostructures are important in the emerging field of nanoscience, because of the tunability of the properties of these structures. Nanostructures based on molecular interactions can be manipulated by selectively modifying specific functional groups while leaving the rest of the structures unchanged. Immobilization of molecules on a surface is required for many applications. Therefore, to achieve a suitable nanostructure one must consider not only interactions between the molecules themselves but also between the molecules and the surface. These collective interactions play an important role for the functional design of the systems. This thesis describes the use of covalent reactions and noncovalent interactions at interfaces, interacting vertically or laterally, for the construction of molecular assemblies. With the use of such molecular interactions, several functional molecules have been employed as the building blocks for nanostructures. The results presented in this thesis illustrate the versatility of the combined molecular interactions, covalent and noncovalent, in creating functional micro/nanostructures at interfaces. Reactive monolayers serve as bottom-up platforms to introduce different functionalities via covalent attachment, while the orthogonal functionalities on the surface open the possibility to immobilize target molecules via complementary covalent or noncovalent interactions. Different supramolecular assemblies on surfaces demonstrate that different nanostructures can be obtained by combining the specificity and stability of multiple supramolecular interactions. Such systems allow the exploration of intermolecular processes, e.g. energy transfer or electron transfer. The fundamental understanding of the molecular interactions in self-assembled nanostructures at interfaces opens new approaches in the design of more advanced nanofabrication schemes.