Hydrophobic Assembly of Metal Nanoclusters on Electrografted Glassy Carbon Electrodes

Surface nanostructuring via non-covalent interactions, chemical reactions, or adsorption phenomena offers a versatile strategy for engineering solid surfaces with customized catalytic and sensing functionalities. Functionalized substrates, in particular, have been utilized to immobilize nanomaterials, such as nanoparticles and nanotubes, thereby enhancing their optical and electrical properties to enable redox catalysis or biomolecule immobilization, including enzymes. In this thesis, I first investigated the electrografting of long saturated aliphatic-chain carboxylates onto glassy carbon electrodes to form hydrophobic surface films. Contrary to previous reports where saturated alkyl-chain carboxylates (up to hexanoate) require mediated oxidation for covalent grafting, my results demonstrate that direct electrochemical oxidation of longer-chain carboxylates successfully yields covalently bound hydrophobic layers, eliminating the need for mediators. Subsequently, I evaluated the capacity of these hydrophobic electrodes to entrap atomically precise gold nanoclusters (AuNCs) through van der Waals interactions and/or the hydrophobic effect between the electrode’s aliphatic chains and the organic ligand shell of the nanoclusters. Specifically, I employed Au25(SR)18 nanoclusters (where SR = SC8H17) to show that the hydrophobic electrodes not only enable adsorption of the nanoclusters but also enhance their electrochemical stability in challenging environments, such as acetonitrile or water. Overall, this work broadens the scope of electrografted surfaces as platforms for assembling hydrophobic nanostructures, with potential applications in biosensing and biocatalysis.