Friction and pull-off forces on submicron-size asperities

Ando, Yasuhisa; Ino, Jiro

doi:10.1016/s0043-1648(97)00158-0

Cited by 74 publications

(49 citation statements)

References 5 publications

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“…The reduced Laplace pressure in the meniscus and the surface tension of the liquid cause an attractive force [53]. Many experiments showed a significant dependency of the adhesion force on the vapor pressure [52,[54][55][56][57].…”

Section: Introductionmentioning

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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Section: Introductionmentioning

confidence: 99%

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

et al. 2006

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“…Condensation of water forms a meniscus bridge that causes an attractive force 2,9) , which is given by ( )…”

Section: Mechanism Of the Decrease In Adhesion Forcementioning

confidence: 99%

“…High performance hard coatings such as diamond-like carbon (DLC) films 1) and improved surfaces with nanostructures 2) are being investigated with respect to their friction reduction properties. Based on their references, the tribological properties of DLC films with nanostructures are expected to improve, but have not yet been studied.…”

Section: Introductionmentioning

confidence: 99%

Friction Properties of the DLC Film with Periodic Structures in Nano-scale

et al. 2006

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Reduction of friction at very low normal loads and for very small contact areas is important for the development of micro devices. High performance hard coatings such as diamond-like carbon (DLC) films and improved surfaces with nanostructures are being investigated with respect to their friction reduction properties. Previously, difficulties associated with the production of nano-scale periodic structures in DLC films have prohibited the study of such films. In the present study, the friction properties of the DLC film with periodic structures were investigated at the nano-scale using an atomic force microscope (AFM). These periodic structures were generated on the surface of the DLC film by means of a femtosecond (fs) laser having the fluence near the ablation threshold. Friction tests were carried out under normal loads ranging from 20 nN to 130 nN, and the frictional directions were 0°, 45° and 90° (relative to the line along which the periodic structures were created). The lateral force of the DLC film with the periodic structures was lower than that of the film without the periodic structures. We have concluded that decreases in adhesive forces produce significant decreases in lateral forces for the same normal loads.

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“…It is expected that the roughness of the surface changes, since micro particles like dust are absorbed over the surface and exert some influence on the surface forces between micro contact surfaces. Based on the tenet that surface force is influenced by contact shape, Y. Ando et al (18) investigated the frictional force and pull-off force of the contact area by controlling the contact shape at the submicron scale. G. W. Tormoen et al (19) demonstrated that roughness is a contingent cause of pull-off force, and that pull-off force relies on the contact position of the asperity array by experimentation on an AFM using a cantilever glued to a glass sphere and the asperity array.…”

Section: Introductionmentioning

confidence: 99%

Cleaning of Dust between Interactive Contact Surfaces by Application of Normal Loads of Artificial Stainless-Cantilever in AFM

Choi

Horie

Ando

2007

JAMDSM

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In this study, we investigated that interactive contact surfaces were affected by dust and applied normal loads of cantilever such as bristles. In order to study the effect of interactive contact surfaces, spherical particles (dry borosilicate glass sphere, plastic sphere) with curvature radius(R=5µm, R=10µm) were glued to artificial stainless cantilevers (spring constant k=576.7N/m). The experiments were performed on various normal applied loads using an AFM (Atomic force microscope). The results indicate that spheres with a small curvature radius removed dust more effectively than did either of those with a large curvature radius, abraded by using the stainless cantilever, over the wide contact area (50µmx50µm). The plastic spheres tend to deform more than do the borosilicate glass spheres under the same applied load and the spheres with a smaller curvature radius tend to deform than do those with a larger curvature radius and the same material properties. Therefore, it had an influence on interactive surface forces. Restructuring dust aggregates by sliding a cantilever, as well as applying loads and contact pressure, forms a new micro contact area, which influences micro surface forces.

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Friction and pull-off forces on submicron-size asperities

Cited by 74 publications

References 5 publications

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

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

Friction Properties of the DLC Film with Periodic Structures in Nano-scale

Cleaning of Dust between Interactive Contact Surfaces by Application of Normal Loads of Artificial Stainless-Cantilever in AFM

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