Modelling and nanoscale force spectroscopy of frequency modulation atomic force microscopy

Abstract

In this paper, a simulation model for frequency modulation atomic force microscopy (FM-AFM) operating in constant amplitude dynamic mode is presented. The model is based on the slow time varying function theory. The mathematical principles to derive the dynamical equations for the amplitude and phase of the FM-AFM cantilever-tip motion is explained and the stability and performance of its closed-loop controller to keep the amplitude at constant value and phase at 90 o is analysed. Then, the performance of the theoretical model is supported by comparison of numerical simulations and experiments. Furthermore, the transient behaviour of amplitude, phase and frequency shift of FM-AFM is investigated and the effect of controller gains on the transient motion is analysed. Finally, the derived FM-AFM model is used to simulate the single molecule/nanoscale force spectroscopy and study the effect of sample viscosity, stiffness and Hamaker constant on the response of FM-AFM.

Addressing the Silent Spread of Monkeypox Disease with Advanced Analytical Tools

“…There are two major operational modes in dynamic AFM, amplitude modulation (AM-AFM) and frequency modulation (FM-AFM). [146] Due to the short contact between the tip and surface, in dynamic AFM, the friction is kept down, also the probability of damage to the tip or specimen is considerably decreased. To explore more information and properties from biomaterials like proteins, cells, tissues, and viruses and increase the spatiotemporal resolution, recently advanced AFM methods such as multifrequency, high-speed multiparametric and molecular recognition imaging modes have been developed.…”

“…There are two major operational modes in dynamic AFM, amplitude modulation (AM‐AFM) and frequency modulation (FM‐AFM). [ 146 ]…”

Investigation on the Impact of Excitation Amplitude on AFM-TM Microcantilever Beam System’s Dynamic Characteristics and Implementation of an Equivalent Circuit

“…The atomic force microscope (AFM) is a prominent nanoscale measurement instrument. Its fundamental operating principle involves converting the van der Waals forces between atoms into displacement signals, which can be detected by the photoelectric detection system via the micro-cantilever beam system and the pressure change detection system [ 4 , 5 , 6 , 7 ]. By analyzing the alteration of the displacement signal, the morphological characteristics of the sample’s surface can be elucidated.…”

Dynamic analysis of flexural vibration mode of an atomic force microscope cantilever with a sidewall probe in liquid

“…The atomic force microscope (AFM) has a significant ability of imaging surface topography of materials in nano and atomic scales. The conventional cantilever with a sharp tip plays an important role in AFM measurement (Deng et al, 2015; Garcia & Perez, 2002; Korayem & Esmaeilzadehha, 2019; Li et al, 2018; Payam, 2020). However, nanoscale surface measurement at sidewalls cannot be performed with the conventional cantilevers and another type of cantilever‐probe system should be used.…”