Tapping Mode AFM Imaging for Functionalized Surfaces

Candoni, Nadine

doi:10.5772/36425

Cited by 5 publications

(3 citation statements)

References 96 publications

(102 reference statements)

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“…So, even if the contact mode imaging is the only AFM technique which can obtain high resolution images, the rough samples with extreme changes in vertical topography being more easily scanned, still the combination of lateral forces and high normal forces can result in reduced spatial resolution and may damage soft samples like polymers (Tsukruk and Singamaneni, ), due to scraping between the tip and the sample. In contrast, the tapping mode AFM imaging uses oscillation of the cantilever tip at or near its natural resonant frequency while allowing the tip to impact the sample for a very short time (Mourougou‐Candoni, ). This intermittent contact minimizes the inelastic polymer surface deformation and the damage done to the tip.…”

Section: Resultsmentioning

confidence: 97%

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Stoica

Hitruc²,

Ţîmpu³

et al. 2015

Scanning

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Several atomic force microscopy (AFM) tests have been carried out on both smooth (polyimide) and rough (polyurethane) surfaces so that to obtain the best results; subsequently, the optimization of experiments performed is presented. A special emphasis has been put on the effect of tip geometry, image pre-processing procedure, scanning area, resolution, pixel size, and cantilever oscillation amplitude in tapping mode, as well as on the quality of the topographical images and 3D surface texture parameters. After viewing the scanning tip and finding out its sharpness, degradation, and contamination, a simultaneous calibration in X, Y, and Z directions, lateral calibration of SPM scanners and detection of lateral non-linearity, hysteresis, creep, and cross-coupling effects has been made. We have established the following experimental parameters: proper scanning resolution (512 × 512 pixels), adequate pixel size (between 2.9 and 19.5 nm) and suitable intermittent contact region (moderate tapping) for which the AFM images present good contrast and resolution. Using these parameters, the values of 3D texture parameters remain constant. These kinds of measurements are extremely important to conduct further AFM experiments on polyimide and polyurethane surfaces under optimal conditions, thus avoiding unwanted artifacts on the morphological images or unrealistic values for the 3D surface texture parameters that might occur.

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Section: Resultsmentioning

confidence: 97%

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Stoica

Hitruc²,

Ţîmpu³

et al. 2015

Scanning

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“…Tuning of the tips was done automatically through instrument software (NanoScope version 8.15). Both topographic [14] and phase [24] images of 40 µm x 40 µm (1600 µm 2 ) scan areas were recorded. The root-mean-square (RMS) surface roughness was calculated as the standard deviation of all the height values within an image area using Nanoscope Analysis_v1.40 image processing software.…”

Section: Atomic Force Microscopy (Afm) Imaging and Surface Roughness mentioning

confidence: 99%

Development and Preliminary Evaluation of a System to Rapidly Measure Coefficient of Friction on Soft Contact Lenses

Hook¹,

Lusignan²,

Wyglądacz³

et al. 2019

IJOVS

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This study was undertaken to 1. develop an apparatus to rapidly measure coefficient of friction (COF) on soft contact lenses; 2. determine if COFs measured on two daily-disposable lens models before and after wear are consistent with changes in lens surface morphology observed in parallel atomic force microscopy (AFM) images. Methods: A stress rheometer was adapted to measure COF on a soft contact lens by custom fabrication of a rapid-mount sample stage for increased throughput. Five subjects were randomly assigned to wear daily disposable nesofilcon A and delefilcon A contact lenses bilaterally for 4 hours, after which time lenses were removed. Static and kinetic COFs of lenses worn on left eyes was measured, while lenses worn on right eyes were imaged in parallel by AFM in tapping mode. Root mean square (RMS) surface roughness was calculated for all lenses to determine the effect of wear on surface topography. Results: Both static and kinetic COFs measured on unworn delefilcon A silicone hydrogel lenses were greater than on nesofilcon A traditional hydrogel lenses. Static COF on nesofilcon A increased significantly after wear, while kinetic COF trended higher but did not change significantly. Similarly, static COF on delefilcon A also increased significantly after wear, and kinetic COF trended higher but did not change significantly, both remaining greater than on worn nesofilcon A. Parallel AFM analysis demonstrated that nesofilcon A lenses are smoother than are delefilcon A out of the package. Both lenses attracted deposits during wear, but the nesofilcon A surface was less altered by on-eye wear than was the delefilcon A surface. Conclusion: A system to rapidly measure static and kinetic COFs was successfully developed. Static and kinetic COFs measured on delefilcon A were greater than on nesofilcon A lenses. More deposits and greater surface roughness were observed after wear on delefilcon A relative to nesofilcon A. Parallel AFM images of worn and unworn lenses were not predictive of measured COFs, but increased roughness visible by AFM was consistent with observed increases in COF, although not all increases were statistically significant.

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“…Atomic force microscopy (AFM) is the one of the most commonly used techniques when the studies with atomic level precision of the material's surface structure and properties are considered (Binnig et al ., ; Giessibl, ; Dulebo et al ., ; Platz et al ., ). Among various AFM operational modes, tapping mode (TM), including its extension, called phase imaging (PI), is the one of the operational modes of AFM, which allows for analysis of surface properties (Mourougou‐Candoni, ), providing high‐resolution images. Due to little or no contact between the tip and the sample, TM is advantageous for studying various materials (metals, ceramics, polymers, composites, biological samples etc.).…”

Section: Introductionmentioning

confidence: 99%

Phase imaging quality improvement by modification of AFM probes’ cantilever

Skibiński

Rębiś

Kaczmarek

et al. 2017

Journal of Microscopy

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Imaging of the surface of materials by atomic force microscopy under tapping and phase imaging mode, with use of modified probes is addressed. In this study, the circularly shaped holes located in varying distance from the probe base, were cut out by focused ion beam. Such modification was a consequence of the results of the previous experiments (probe tip sharpening and cantilever thinning) where significant improvement of image quality in tapping and phase imaging mode has been revealed. The solution proposed herein gives similar results, but is much simpler from the technological point of view. Shorter exposition time of the tip onto gallium ions during FIB processing allows to reduce material degradation. The aim of this modification was to change harmonic oscillators' properties in the simplest and fastest way, to obtain stronger signal for higher resonant frequencies, which can be advantageous for improving the quality of imaging in PI mode. Probes shaped in that way were used for AFM investigations with Bruker AFM nanoscope 8. As a testing material, titanium roughness standard sample, supplied by Bruker, was used. The results have shown that the modifications performed within these studies influence the oscillation of the probes, which in some cases may result in deterioration of the imaging quality under tapping mode for one or both self-resonant frequencies. However, phase imaging results obtained using modified probes are of higher quality. The numerical simulations performed by application of finite element method were used to explain the results obtained experimentally. Phenomenon described within this study allows to apply developed modelling methodology for prediction of effects of various modifications on the probes' tip, and as a result, to predict how proposed modifications will affect AFM imaging quality.

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Tapping Mode AFM Imaging for Functionalized Surfaces

Cited by 5 publications

References 96 publications

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Development and Preliminary Evaluation of a System to Rapidly Measure Coefficient of Friction on Soft Contact Lenses

Phase imaging quality improvement by modification of AFM probes’ cantilever

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