Critical phenomena of water bridges in nanoasperity contacts

He, Mingyan; Blum, Amy Szuchmacher; Aston, D. Eric; Buenviaje, Cynthia; Overney, René M.; Luginbühl, Reto

doi:10.1063/1.1331298

Cited by 182 publications

(181 citation statements)

References 30 publications

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“…In other case, adhesion force versus humidity curves showed a maximum [42,58,205] or a step like increase [69], even on similar surfaces. In cleavage experiments of mica, a decrease in the cleavage force with increasing humidity was observed [70].…”

Section: Influence Of Humidity On Adhesionmentioning

confidence: 99%

“…The influence of relative humidity (RH) on adhesion force is discussed by Harriman and Simkins [185] and Bracken [42,44,46,48,[186][187][188]. The significance of air humidity in powder processing is stressed by Harnby et al [189].…”

Section: Influence Of Humidity On Adhesionmentioning

confidence: 99%

“…Results of other studies showed that meniscus force between silica particles [62,63], a silica particle and a silicon wafer [64], between a silicon nitride tip and molybdenum trioxide [65], or pharmaceutical substances [66], and between silicon wafer and silicon nitride tip was at relative humidity around 70% [67]. In other cases adhesion force-versus-humidity curves showed a maximum [42,58,68], or a step-like increase [69]. On clean, freshly and cleaved mica a decrease of the adhesion force with increasing humidity was observed [70]; because the adhesion force measured above relative humilities 30-40%.…”

Section: Introductionmentioning

confidence: 99%

“…Results of other studies showed that due to the strong capillary condensation (on hydrophilic surfaces), the adhesion force between silicon nitride or silicon AFM tip and different clean and fresh surfaces such as mica and silicon wafer was observed to first increase and then decrease with an increase in humidity [42,58,59]. S. Rozhok et al showed that adhesion force on NaCl substrate is a function of relative humidity too [60].…”

Section: Introductionmentioning

confidence: 99%

“…To describe this mathematically roughness was modeled by a single spherical asperity [39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

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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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