Role of relative humidity in atomic force microscopy imaging

Thundat, Thomas; Zheng, Xingrong; Chen, G.Y.; Warmack, R. J.

doi:10.1016/0039-6028(93)90152-a

Cited by 110 publications

(92 citation statements)

References 14 publications

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“…Often quite different dependencies of adhesion force on humidity are reported for the same system, e.g. for mica [700,706,707], and the increase of adhesion with humidity is either reported to be step-like [694,700], linearly increasing [686,708] or exhibiting a maximum at intermediate values [707,684]. These discrepancies need clarification.…”

Section: Meniscus Forcementioning

confidence: 98%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,145

2,936

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Section: Meniscus Forcementioning

confidence: 98%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,145

2,936

View full text Add to dashboard Cite

“…The adhesion force-versus-humidity curves on silicon wafer surface is as a function of the humidity and noticed that there are three distinct force regimes (Fig.4.22) [42,[207][208][209]. First, at low humidity ( ) adhesion forces are almost constant.…”

Section: Meniscus Force On Hydrophilic Surfacesmentioning

confidence: 99%

On the Adhesion between Fine Particles and Nanocontacts: An Atomic Force Microscope Study

et al. 2006

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To optimize the handling of fine powders in industrial applications, understanding the interaction forces between single powder particles is fundamental. The forces between colloidal particles dominate the behavior of a great variety of materials, including paints, paper, soil, and many industrial processes. With the invention of the atomic force microscope (AFM), the direct measurement of the interaction between single micron-sized particles became possible. The adhesional contact between a particle and a substrate is a parameter for analyzing pull-off force data generated by AFM. The aim of this study was to understand surface interactions between fine particles. I measured the adhesion forces between AFM tips or particles attached to AFM cantilevers and different solid samples. Smooth and homogeneous surfaces such as silicon wafer, mica, or highly oriented pyrolytic graphite (HOPG), and more rough and heterogeneous surfaces such as iron particles or patterns of TiO 2 nanoparticles on silicon wafer were used. First, I addressed to the wellknown issue that AFM adhesion experiment results show wide distributions of adhesion forces rather than a single value. My experimental results show that variations in adhesion forces comprise fast (i.e., from one force curves to the next) random fluctuations and slower fluctuations, which occur over tens or hundreds of consecutive measurements. Slow fluctuations are not likely to be the result of variations in external factors such as lateral position, temperature, humidity, and so forth because those were kept constant. Even if two solid bodies are brought into contact under precisely the same conditions (same place, load, direction, etc.) the result of such a measurement will often not be the same as for the previous contact. The measurement itself will induce structural changes in the contact region which can change the value for the next adhesion force measurement.In the second part I studied the influence of humidity on the adhesion of nanocontacts. Humidity was adjusted relatively fast to minimize tip wear during one experiment. For hydrophobic surfaces, no signification change of adhesion force with humidity was observed. Adhesion force-versus-humidity curves recorded with hydrophilic surfaces either showed a maximum or continuously increased. I demonstrate that the results can be interpreted with simple continuum theory of the meniscus force. The meniscus force is calculated based on a model that includes surface roughness and takes into account different AFM tip (or particle) shapes by a two-sphere-model.Experimental and theoretical results show that the precise contact geometry has a critical influence on the humidity dependence of the adhesion force.Changes of tip geometry on the sub-10-nm length scale can completely change adhesion force-versus-humidity curves. Our model can also explain the differences between earlier AFM studies, where different dependencies of the adhesion force on humidity were observed.Keywords: Atomic force microscopy (AFM), cantile...

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“…It was found that the protein molecules adhered to the mica well enough for measurements only when the humidity was less than 50%, probably because high humidity increases the attractive capillary forces between probe and sample. 12,24,42,43 Humidities of less than 30% were avoided to prevent protein dehydration and possible structural deformations. The effects of controlled hydration on proteins have been studied by scanning tunneling microscopy (STM).…”

Section: Methodsmentioning

confidence: 99%

Imaging the Molecular Dimensions and Oligomerization of Proteins at Liquid/Solid Interfaces

et al. 1998

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Individual Concanavalin A (ConA) molecules have been imaged at the liquid/solid interface with an atomic force microscope (AFM). Three-dimensional sizing with very high resolution (<5 Å) has been obtained by a novel approach based on height distributions, which avoids the tip convolution effects which normally affect scanning probe microscopy techniques. Each height measurement correlates to a particular molecular orientation on the surface. A large number of such measurements provide a statistical ensemble of orientations. The complete height distribution reflects the three-dimensional size of the protein sample and hence its tertiary and quaternary structure. A surface adsorption and orientation model, based on a minimization of surface adsorption energy, is proposed. This model is in good agreement with the observed height distribution of Con A molecules at the liquid/solid interface. Analysis of Con A and succinylated Con A molecules on mica demonstrates that Con A dimers are the prevalent species at the liquid/solid interface. This is in contrast to the tetrameric organization of Con A normally observed in solution. The new possibilities opened by height distribution analysis on the physical characterization of biomolecules at interfaces are also discussed.

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Role of relative humidity in atomic force microscopy imaging

Cited by 110 publications

References 14 publications

Force measurements with the atomic force microscope: Technique, interpretation and applications

Force measurements with the atomic force microscope: Technique, interpretation and applications

On the Adhesion between Fine Particles and Nanocontacts: An Atomic Force Microscope Study

Imaging the Molecular Dimensions and Oligomerization of Proteins at Liquid/Solid Interfaces

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