Hydration Dynamics and the Future of Small-Amplitude AFM Imaging in Air

Santos, Sérgio; Olukan, Tuza; Lai, Chia-Yun; Chiesa, Matteo

doi:10.3390/molecules26237083

“…Additionally, the combination of small free amplitudes and small amplitude setpoints was used for imaging as it was shown by Santos et al . 25 , 26 and Lai et al . 27 that the method can lead to a very close proximity between tip and sample, being essential for high resolution imaging.…”

Section: Introductionmentioning

confidence: 96%

Torsional and lateral eigenmode oscillations for atomic resolution imaging of HOPG in air under ambient conditions

Eichhorn

¹

,

Dietz

²

2022

Sci Rep

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Combined in-plane and out-of-plane multifrequency atomic force microscopy techniques have been demonstrated to be important tools to decipher spatial differences of sample surfaces at the atomic scale. The analysis of physical properties perpendicular to the sample surface is routinely achieved from flexural cantilever oscillations, whereas the interpretation of in-plane sample properties via force microscopy is still challenging. Besides the torsional oscillation, there is the additional option to exploit the lateral oscillation of the cantilever for in-plane surface analysis. In this study, we used different multifrequency force microscopy approaches to attain better understanding of the interactions between a super-sharp tip and an HOPG surface focusing on the discrimination between friction and shear forces. We found that the lateral eigenmode is suitable for the determination of the shear modulus whereas the torsional eigenmode provides information on local friction forces between tip and sample. Based on the results, we propose that the full set of elastic constants of graphite can be determined from combined in-plane and out-of-plane multifrequency atomic force microscopy if ultrasmall amplitudes and high force constants are used.

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“…In the case of a hydrophobic surface, a hydrophobic tip can even evaporate a hydration layer because of the drying transition of water, a phase transition of water in a hydrophobic confinement . Often, a molecular simulation is required to relate F ( z ) to ρ( z ) unambiguously and quantitatively. − …”

Section: Introductionmentioning

confidence: 99%

Molecular Features of Hydration Layers: Insights from Simulation, Microscopy, and Spectroscopy

Ki-Duk

¹

,

Choi

²

,

Zhang

³

et al. 2022

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Water molecules are orderly when stacked on a material surface in a liquid or under ambient conditions. Such a hydration layer plays a crucial role in various chemical and biological processes at interfaces. Significant gaps exist however in our understanding of the molecular structure and dynamics of a hydration layer. Atomic force microscopy (AFM) and vibrational sum frequency generation (VSFG) are widely used to probe the molecular stacking and orientation in a hydration layer. We review the molecular features of a hydration layer extracted from AFM and VSFG and how a molecular simulation can give a clear and quantitative interpretation of these experiments.

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“…Both setups exploit the second flexural eigenmode for the topographical feedback in amplitude modulation (AM) whereas the first torsional, first lateral and third flexural mode are frequency-modulated (FM) and controlled by phase-locked-loops (PLL) electronics. Inspired by the work of colleagues in the field, we used higher flexural eigenmodes 19,20 and small free amplitudes in combination with small amplitude setpoints for imaging [21][22][23] .…”

Section: Introductionmentioning

confidence: 99%

Torsional And Lateral Eigenmode Oscillations For Atomic Resolution Imaging Of HOPG In Air Under Ambient Conditions

Eichhorn

¹

,

Dietz

²

2022

Preprint

0

View full text Add to dashboard Cite

Combined in-plane and out-of-plane multifrequency atomic force microscopy techniques have been demonstrated to be important tools to decipher spatial differences of sample surfaces at the atomic scale. The analysis of physical properties perpendicular to the sample surface is routinely achieved from flexural cantilever oscillations, whereas the interpretation of in-plane sample properties via force microscopy is still challenging. Besides the torsional oscillation, there is the additional option to exploit the lateral oscillation of the cantilever for in-plane surface analysis. In this study, we used different multifrequency force microscopy approaches to attain better understanding of the interactions between a super-sharp tip and an HOPG surface focusing on the discrimination between friction and shear forces. We found that the lateral eigenmode is suitable for the determination of the shear modulus whereas the torsional eigenmode provides information on local friction forces between tip and sample. Based on the results, we propose that the full set of elastic constants of graphite can be determined from combined in-plane and out-of-plane multifrequency atomic force microscopy if ultrasmall amplitudes and high force constants are used.

show abstract

Hydration Dynamics and the Future of Small-Amplitude AFM Imaging in Air

Cited by 3 publications

References 51 publications

Torsional and lateral eigenmode oscillations for atomic resolution imaging of HOPG in air under ambient conditions

Torsional and lateral eigenmode oscillations for atomic resolution imaging of HOPG in air under ambient conditions

Molecular Features of Hydration Layers: Insights from Simulation, Microscopy, and Spectroscopy

Torsional And Lateral Eigenmode Oscillations For Atomic Resolution Imaging Of HOPG In Air Under Ambient Conditions

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