Load-displacement relation in adhesion measurement

Using linear elasticity theory and thermodynamics, a thermodynamics criterion for equilibrium contact between two solid surfaces in atomic force microscopy (AFM) was established, in which the cantilever beam and tip of the AFM were modelled as an elastic spring and a microparticle, respectively. The elastic energy stored in the spring was included in the calculation of system energy. A new relation between the adhesion energy and the displacement of the microparticle at the separation was established, which could be used to calculate the adhesion energy between solid surfaces.