The mechanical response of gold substrates passivated by self-assembling monolayer films

Interfacial force microscopy has been used to show that a single layer of self-assembling molecules adsorbed on a gold substrate can prevent adhesion between gold and a tungsten probe. The passivated gold is able to elastically support large repulsive loads, with plots of load versus deformation closely following the Hertzian model. The gold shear-stress threshold for plastic deformation is determined to be approximately 1 gigapascal, which is in agreement with the theoretical value for the intrinsic gold-lattice stability.