ABSTRACT

When pull-off force measurements on inorganic surfaces are performed in solution, other interactions arise, such as solvation, hydration and hydrophobic forces. The adhesion force studies in solution are still much debated and more complex than measurements of the pull-off force in air, since additional forces arise when an AFM tip is immersed in solution. Repulsive forces may arise from solvation or hydration forces since the water near hydrophilic surfaces is structured. In aqueous solutions, electrical double-layer forces also arise, which may be either attractive or repulsive, and may be present between the surface of the tip and sample [261, 262].