Nanofabrication of two- and three-dimensional structures by multivalent supramolecular interactions

This thesis describes the use of multivalent host-guest interactions at interfaces
for the construction of 2D and 3D nanostructures. Self-assembled monolayers (SAMs) on flat surfaces and nanoparticles have been employed to confine and organize such structures. The host-guest interactions between β-cyclodextrin (CD) and different guest derivatives are the focus of attention in this thesis. Host monolayers of CDs were prepared on flat gold and silicon oxide surfaces. These host monolayers have been utilized as molecular printboards for the recognition and positioning of molecules by means of multiple supramolecular interactions. Gold nanoparticles have also been modified with CD and the formation of large 3D aggregates in the presence of multivalent guest molecules was studied as a function of the number of hydrophobic endgroups of the guest molecule and its geometry. The combination of multiple interactions between adamantyl-terminated dendrimers and CD-modified gold nanoparticles (CD Au NPs) was employed to create organized 2D structures at surfaces generated by layer-by-layer assembly. The combination with lithographic techniques, by which such structures can be directed to specific target areas, led to the formation of 3D
nanostructures.