Simulation of surface force apparatus

(Theoretical analyses of interaction between sphere and plane)

Abstract

Simulation of the surface force apparatus (SFA: ESF-5000K, Elionix, Inc.) using elastic contact theory was performed to calculate the surface force and approach distance between sphere and plane. A series of experimental processes from contact to pull-off between a spherical probe and a plane sample was targeted in the simulation, and the mutual displacement of the sphere was calculated using JKR elastic contact theory and the van der Waals interaction force. In this study, the glass (BK7) was used for the spherical probe, while Si and Pt were used for the plane samples. Comparison of the theoretical calculation results with the experimental results confirmed the validity of the simulations and clarified the contact properties between the sphere and plane sample. The difference between the refractive index of the actual material and the ideal value may cause the theoretical curve to deviate from the experimental results.