Computational Development of Single- and Dual-Frequency Modulation Atomic Force Spectroscopy for Ambient Air Applications

2009 ◽  
Author(s):  
Gaurav Chawla ◽  
Santiago D. Solares
Keyword(s):  
Frequency Modulation ◽  
Force Spectroscopy ◽  
Ambient Air ◽  
Interaction Force ◽  
Single Frequency ◽  
Dual Frequency ◽  
Rapid Acquisition ◽  
Atomic Force ◽  
Modulation Mode ◽  
Force Curves

The ability of atomic force microscopy (AFM) to acquire tip-sample interaction force curves has allowed researchers to understand the mechanical behavior of numerous materials at the nanoscale. However, AFM force spectroscopy with the most commonly used techniques can be a slow process for non-uniform samples, as it often requires the measurement to be performed at one fixed surface point at a time. In this paper we present two dynamic AFM based spectroscopy methods, one requiring operation in single-frequency-modulation mode and another using dual-frequency-modulation, which could allow a more rapid acquisition of topography and tip-sample interaction force curves. Numerical simulation results are provided along with discussions on the benefits and limitations of both.

scholarly journals Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

2012 ◽  
Vol 3 ◽  
pp. 336-344 ◽  
Author(s):  
Miriam Jaafar ◽  
David Martínez-Martín ◽  
Mariano Cuenca ◽  
John Melcher ◽  
Arvind Raman ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Amplitude Modulation ◽  
Frequency Modulation ◽  
Driving Force ◽  
Oscillation Amplitude ◽  
Dynamic Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Modulation Mode ◽  
Feedback Scheme

We introduce drive-amplitude-modulation atomic force microscopy as a dynamic mode with outstanding performance in all environments from vacuum to liquids. As with frequency modulation, the new mode follows a feedback scheme with two nested loops: The first keeps the cantilever oscillation amplitude constant by regulating the driving force, and the second uses the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different environments. Drive-amplutide modulation is a very stable, intuitive and easy to use mode that is free of the feedback instability associated with the noncontact-to-contact transition that occurs in the frequency-modulation mode.

Synergy of Resonant Oscillatory Modes in Atomic Force Microscopy of Polymers

MRS Advances ◽  
2016 ◽  
Vol 1 (25) ◽  
pp. 1853-1858 ◽  
Author(s):  
Sergei Magonov ◽  
Sergey Belikov ◽  
John Alexander ◽  
Marko Surtchev
Keyword(s):  
Atomic Force Microscopy ◽  
Amplitude Modulation ◽  
Frequency Modulation ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Heterogeneous Samples ◽  
Modulation Mode

ABSTRACTThe set of oscillatory resonance AFM modes is expanded with frequency modulation mode and frequency imaging in amplitude modulation mode. The backgrounds of these modes are discussed and their capabilities are compared on the practical examples. The data show how these techniques complement the amplitude modulation with phase imaging. The frequency imaging enhances the compositional mapping of heterogeneous samples. Frequency modulation mode provides a superior capability in imaging at low tip-sample forces.

scholarly journals Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case

2013 ◽  
Vol 4 ◽  
pp. 198-207 ◽  
Author(s):  
Daniel Ebeling ◽  
Santiago D Solares
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Operation Mode ◽  
Excitation Amplitude ◽  
Open Loop ◽  
Constant Frequency ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Modulation Mode

We present an overview of the bimodal amplitude–frequency-modulation (AM-FM) imaging mode of atomic force microscopy (AFM), whereby the fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in which the higher eigenmode is driven with constant frequency and constant excitation amplitude. General as well as particular characteristics of the different driving schemes are highlighted from theoretical and experimental points of view, revealing the advantages and disadvantages of each. This study provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way.

scholarly journals Atomic Force Spectroscopy on Poly(o-ethoxyaniline) Nanostructured Films: Sensing Nonspecific Interactions

2007 ◽  
Vol 13 (4) ◽  
pp. 304-312 ◽  
Author(s):  
F.L. Leite ◽  
C.E. Borato ◽  
W.T.L. da Silva ◽  
P.S.P. Herrmann ◽  
O.N. Oliveira ◽  
...  
Keyword(s):  
Pure Water ◽  
Force Spectroscopy ◽  
Film Morphology ◽  
Atomic Force Spectroscopy ◽  
Ph Values ◽  
Atomic Force ◽  
Force Curves ◽  
Liquid Cell ◽  
Nonspecific Interactions ◽  
Nanostructured Layers

Atomic force spectroscopy (AFS) was used to measure interaction forces between the tip and nanostructured layers of poly(o-ethoxyaniline) (POEA) in pure water and CuSO4solutions. When the tip approach and retraction were carried out at low speeds, POEA chains could be physisorbed onto the Si3N4tip via nonspecific interactions. We conjecture that while detaching, POEA chains were stretched and the estimated chain lengths were consistent with the expected values from the measured POEA molecular weight. The effects from POEA doping could be investigated directly by performing AFS measurements in a liquid cell, with the POEA film exposed to liquids of distinct pH values. For pH ≥ 6.0, the force curves normally displayed an attractive region for POEA, but at lower pH values—where POEA is protonated—the repulsive double-layer forces dominated. Measurements in the liquid cell could be further exploited to investigate how the film morphology and the force curve are affected when impurities are deliberately introduced in the liquid. The shape of the force curves and the film morphology depended on the concentration of heavy metal in the liquid cell. AFS may therefore be used to study the interaction between film and analyte, with important implications for the understanding of mechanisms governing the sensing ability of taste sensors.

Quartz tuning fork-based frequency modulation atomic force spectroscopy and microscopy with all digital phase-locked loop

2012 ◽  
Vol 83 (11) ◽  
pp. 113705 ◽  
Author(s):  
Sangmin An ◽  
Mun-heon Hong ◽  
Jongwoo Kim ◽  
Soyoung Kwon ◽  
Kunyoung Lee ◽  
...  
Keyword(s):  
Frequency Modulation ◽  
Tuning Fork ◽  
Force Spectroscopy ◽  
Quartz Tuning Fork ◽  
Phase Locked Loop ◽  
Atomic Force Spectroscopy ◽  
Digital Phase ◽  
Atomic Force
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