Utilization of simple scaling laws for modulating tip-sample peak forces in atomic force microscopy characterization in liquid environments.

The dynamics of atomic force microscopy (AFM) microcantilevers in liquid environments have been previously shown to be extremely complex and nonlinear, exhibiting phenomena such as momentary excitation of higher eigenmodes, fluid-borne excitation, mass loading, and the emergence of sub-harmonic responses. It has also been shown that the signals acquired by the instrument can differ significantly between tip- and base-excited cantilevers in highly damped environments, such that it can be difficult for users to modulate the peak impact forces for base-excited AFM systems that are not equipped with advanced force spectroscopy tools. Despite the dynamic complexity, we show that through understanding of simple scaling laws based on the damped harmonic oscillator model and operation at high amplitude setpoints, it is possible to modulate the tip-sample forces, which could be useful in studies that require experiments involving different but controllable peak force levels. [ABSTRACT FROM AUTHOR]