How do thiols attach to gold surfaces in nanotechnology?

In nanotechnology, long-chain alkanethiols attach to metallic gold surfaces by forming self-assembled monolayers (SAMs). These thiols function as a "molecular alligator clip," binding to the gold through a strong gold-sulfur interaction with a binding energy of approximately 160 kilojoules per mole (kJ/mol).1

The organization of these monolayers is driven by this substantial binding energy, as well as by lateral van der Waals forces between the tethered alkyl chains, which contribute an additional 10–20 kJ/mol to the stability of the structure. These SAMs can be prepared on both planar (two-dimensional) surfaces and on nanoparticles (three-dimensional surfaces), the latter of which are referred to as monolayer-protected clusters (MPCs).1