Study of the influence of adsorbed water on AFM friction measurements on molybdenum trioxide thin films

Thin films of layered oxide α-MoO3 have been prepared by reactive magnetron sputtering. On these films we have measured friction forces and adhesive forces at the microscopic scale with an AFM, under ambient and humidity controlled conditions. We show that surface crystallinity and orientation induce local values of the microscopic friction coefficient. The correlation between water adsorption, adhesion and friction is discussed.