Quantitative Mechanical Properties of Carbon-based Surfaces Examined through Analysis of Cantilever Dynamics in Atomic Force Microscopy
Date
2021-05-12
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Abstract
Mechanical properties of nanomaterials have been at the forefront of recent scientific interest, as a reduction in the feature size of these materials can introduce a significant improvement in their mechanical properties. To investigate the nanoscale mechanical properties, researchers have employed a variety of instruments and techniques such as nanoindentation and dynamic atomic force microscopy (AFM). Although these techniques have been successful in providing a qualitative assessment of the mechanical properties of the surfaces, quantification of the experimental data has been hindered due to the lack of precisely calibrated data. Additionally, novel applications of nanomaterials require high spatial and temporal resolution in their mechanical properties, which have not been achieved in current characterization methods. To begin to address these issues, dynamic AFM was operated under ultrahigh vacuum (UHV) conditions to determine the elastic modulus of the novel materials down to the atomic length-scale. Considering the cantilever shape in a dynamic contact, calibration of the experimental data was implemented to extract a quantitative elastic modulus and a spatially-resolved map of this value on graphite and graphene surface. The developed experimental technique and calibration method were verified through the comparison with both analytical and simulation models of the surface. Following the quantification of the high spatial resolution of mechanical properties of two-dimensional materials, an advanced technique is introduced and developed to measure the variation of the mechanical properties through the spectral/frequency analysis of the conventional static cantilever bending data acquired at high sampling rates on the order of ∼1 MHz. The results of this dissertation are promising as they confirm the ability of these techniques to provide high-fidelity in spatial resolution of the mechanical properties of nanomaterials. Furthermore, they can be used in several industries such as aerospace, design and manufacturing, and microelectromechanical systems (MEMS), where the techniques can be utilized for the more efficient assessment of the functionality of nanomaterials in such applications. Furthermore, the results of this research demonstrate the importance of frequency analysis in advanced microscopy techniques.
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Keywords
Atomic force microscopy, Surface imaging, Graphene
Citation
Abooalizadeh, Z. (2021). Quantitative Mechanical Properties of Carbon-based Surfaces Examined through Analysis of Cantilever Dynamics in Atomic Force Microscopy (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.