Quartz-crystal microbalance studies of the velocity dependence of interfacial friction

Mak, C.; Krim, J.

doi:10.1103/physrevb.58.5157

Cited by 60 publications

(23 citation statements)

References 14 publications

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“…They showed t s was constant over a wide range of frequency and amplitude. The frequency is difficult to vary in experiment, but Mak and Krim (1998) found that t s was independent of amplitude in both fluid and crystalline phases of Kr on Au. Tomassone et al (1997) have used two additional techniques to determine t s .…”

Section: E Frenkel-kontorova Model In Two Dimensions: Adsorbed Monolmentioning

confidence: 99%

Computer Simulations of Friction, Lubrication, and Wear

Robbins¹,

Müser²

2000

Mechanics &Amp; Materials Science

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Computer simulations have played an important role in understanding tribological processes. They allow controlled numerical "experiments" where the geometry, sliding conditions and interactions between atoms can be varied at will to explore their effect on friction, lubrication, and wear. Unlike laboratory experiments, computer simulations enable scientists to follow and analyze the full dynamics of all atoms. Moreover, theorists have no other general approach to analyze processes like friction and wear. There is no known principle like minimization of free energy that determines the steady state of non-equilibrium systems. Even if there was, simulations would be needed to address the complex systems of interest, just as in many equilibrium problems.Tremendous advances in computing hardware and methodology have dramatically increased the ability of theorists to simulate tribological processes. This has led to an explosion in the number of computational studies over the last decade, and allowed increasingly sophisticated modeling of sliding contacts. Although it is not yet possible to treat all the length scales and time scales that enter the friction coefficient of engineering materials, computer simulations have revealed a great deal of information about the microscopic origins of static and kinetic friction, the behavior of boundary lubricants, and the interplay between molecular geometry and tribological properties. These results provide valuable input to more traditional macroscopic calculations. Given the rapid pace of developments, simulations can be expected to play an expanding role in tribology.In the following chapter we present an overview of the major results from the growing simulation literature. The emphasis is on providing a coherent picture of the field, rather than a historical review. We also outline opportunities for improved simulations, and highlight unanswered questions.We begin by presenting a brief overview of simulation techniques and focus on special features of simulations for tribological processes. For example, it is well known that the results of tribological experiments can be strongly influenced by the mechanical properties of the entire system that produces sliding. In much the same way, the results from simulations depend on how relative motion of the surfaces is imposed, and how heat generated by sliding is removed. The different techniques that are used are described, so that their influence on results can be understood in later sections.The complexities of realistic three-dimensional systems can make it difficult to analyze the molecular mechanisms that underly friction. The third section focuses on dry, wearless friction in less complex systems. The discussion begins with simple one-dimensional models of friction between crystalline surfaces. These models illustrate general results for the origin and trends of static and kinetic friction, such as the importance of metastability and the effect of commensurability. Then two-dimensional studies are described, with an emphasis ...

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Section: E Frenkel-kontorova Model In Two Dimensions: Adsorbed Monolmentioning

confidence: 99%

Computer Simulations of Friction, Lubrication, and Wear

Robbins¹,

Müser²

2000

Mechanics &Amp; Materials Science

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“…2d). This model is extensively used for the interpretation of nanotribological experiments with the QCM [20]. We consider the drag coefficient of the dashpot,ξ S , to be a fixed parameter independent of frequency.…”

Section: Loading With a Mass In Series With A Dashpotmentioning

confidence: 99%

“…Nanotribology has also gained much from the QCM, where the early work has been done by J. Krim [19,20]. The Krim group studied adsorbed monolayers of noble gas atoms onto the electrode and observed an increase in dissipation.…”

Section: Introductionmentioning

confidence: 98%

Studies of Contact Mechanics with the QCM

Johannsmann

Piezoelectric Sensors

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“…The possibility of slip was discussed until recently, in mainstream literature, only in the context of the flow of polymer melts [11,12], though over the years persistent doubts were expressed [13]. No-slip contrasts with slip characteristic of highly viscous polymers [11,12], monolayers of gas condensed on vibrated solids [14], superfluid helium [15], moving contact lines of liquid droplets on solids [16], and kinetic friction of liquid films less than 5-10 molecular dimensions thick [17,18]. However, experimental capability and technical needs have changed -especially so with the emerging interest in microfluidics and microelectromechanical system (MEMS)-based devices.…”

Section: Hydrodynamic Force Of Fluids Flowing In Microto Nanofluidicsmentioning

confidence: 99%

Interfacial Forces and Spectroscopic Study of Confined Fluids

Zhu

Mukhopadhyay

Granick

2011

Nanotribology and Nanomechanics II

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In this chapter we discuss three specific issues which are relevant for liquids in intimate contact with solid surfaces. (1) Studies of the hydrodynamic flow of simple and complex fluids within ultra-narrow channels show the effects of flow rate, surface roughness and fluid-surface interaction on the determination of the boundary condition. We draw attention to the importance of the microscopic particulars to the discovery of what boundary condition is appropriate for solving continuum equations and the potential to capitalize on slip at the wall for purposes of materials engineering. (2) We address the long-standing question of the structure of aqueous films near a hydrophobic surface. When water was confined between adjoining hydrophobic and hydrophilic surfaces (a Janus interface), giant fluctuations in shear responses were observed, which implies some kind of flickering, fluctuating complex at the water-hydrophobic interface. (3) Finally we discuss recent experiments that augment friction studies by measurement of diffusion, using fluorescence correlation spectroscopy (FCS). Here spatially resolved measurements showed that translation diffusion slows exponentially with increasing mechanical pressure from the edges of a Hertzian contact toward the center, accompanied by increasingly heterogeneous dynamical responses. This dynamical probe of how liquids order in molecularly thin films fails to support the hypothesis that shear produces a melting transition.

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Quartz-crystal microbalance studies of the velocity dependence of interfacial friction

Cited by 60 publications

References 14 publications

Computer Simulations of Friction, Lubrication, and Wear

Computer Simulations of Friction, Lubrication, and Wear

Studies of Contact Mechanics with the QCM

Interfacial Forces and Spectroscopic Study of Confined Fluids

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