A PLATFORM FOR OBSERVING THE BEHAVIOR OF AFM CANTILEVERS DURING QUASI-STATIC LOADING

摘要

This paper describes a platform for studying the bending behavior of ultra-compliant (stiffness less than 1 N/m) atomic force microscope (AFM) cantilevers. The fundamental issue is that a cantilever does not represent an ideal design for precision force measurement due to the parasitic motion of the tip under load. For ultra-compliant cantilevers, the combination of a high adhesive force at the tip and parasitic motion can lead to proportionally substantial lateral (in-plane) forces. In addition, the tip-surface adhesive force can increase the propensity for sticking which is a considerable concern for colloidal probes due to the increased contact surface. These effects can manifest as deviate bending behavior and have been suggested as confounding contact style forcerncalibration/measurement [1] since force is commonly related to tip displacement by an assumed bending model.