Knudsen forces on microcantilevers

Passian, Ali; Wig, A.; Mériaudeau, Fabrice; Ferrell, T. L.; Thundat, Thomas

doi:10.1063/1.1515108

Cited by 65 publications

(51 citation statements)

References 27 publications

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“…Both the frequency and the bending undergo variations as a function of the pressure. Although the origin of such variations is still under investigation, the acquired data are in accordance with the reported results, where similar variations in the frequency and bending as a function of pressure and temperature were examined in various pressure regimes from the continuum to free molecular [19][20][21][22][23]. Fig.…”

Section: Effects Of Ambient Mediasupporting

confidence: 80%

An experimental investigation of analog delay generation for dynamic control of microsensors and atomic force microscopy

Passian

Lereu

et al. 2007

Ultramicroscopy

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Section: Effects Of Ambient Mediasupporting

confidence: 80%

An experimental investigation of analog delay generation for dynamic control of microsensors and atomic force microscopy

Passian

Lereu

et al. 2007

Ultramicroscopy

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“…The flexural phonon flux flowing from hot to cold cedes some of its physical momentum by scattering onto the adsorbed cluster, which is ballistically transported. Previously known examples of ballistic phoresis include the Knudsen force exerted by gas particles on tips, described by Passian et al (52) and observed by Gotsmann and Dürig (53). The phonon-induced ballistic thermophoresis described here is specific to submicrometer sheet sizes and will eventually disappear as flexural phonons evolve from ballistic to diffusive once the sheet length L is large enough, a crossover which our simulations do not yet detect at L ∼ 150nm.…”

Section: Discussionmentioning

confidence: 76%

Ballistic thermophoresis of adsorbates on free-standing graphene

Panizon

Guerra

Tosatti

2017

Proc. Natl. Acad. Sci. U.S.A.

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The textbook thermophoretic force which acts on a body in a fluid is proportional to the local temperature gradient. The same is expected to hold for the macroscopic drift behavior of a diffusive cluster or molecule physisorbed on a solid surface. The question we explore here is whether that is still valid on a 2D membrane such as graphene at short sheet length. By means of a nonequilibrium molecular dynamics study of a test system-a gold nanocluster adsorbed on free-standing graphene clamped between two temperatures ∆T apart-we find a phoretic force which for submicron sheet lengths is parallel to, but basically independent of, the local gradient magnitude. This identifies a thermophoretic regime that is ballistic rather than diffusive, persisting up to and beyond a 100-nanometer sheet length. Analysis shows that the phoretic force is due to the flexural phonons, whose flow is known to be ballistic and distance-independent up to relatively long mean-free paths. However, ordinary harmonic phonons should only carry crystal momentum and, while impinging on the cluster, should not be able to impress real momentum. We show that graphene and other membrane-like monolayers support a specific anharmonic connection between the flexural corrugation and longitudinal phonons whose fast escape leaves behind a 2D-projected mass density increase endowing the flexural phonons, as they move with their group velocity, with real momentum, part of which is transmitted to the adsorbate through scattering. The resulting distance-independent ballistic thermophoretic force is not unlikely to possess practical applications.thermophoresis | graphene | ballistic | flexural phonons | heat transport T hermophoresis is the phenomenon by which a body immersed in a fluid endowed with a temperature gradient experiences a force and, independent of convection, drifts from hot to cold (1). We address here the less common case of thermophoresis of a physisorbed nanoobject caused by an in-plane temperature imbalance in the underlying solid substrate surface. Recent years have seen a surge of interest for methods to control nanoscale transport and manipulation, also in view of potential applications in nanodevices. The possibility to drive directional motion of adsorbates by means of thermal gradients is interesting and has been explored both theoretically (2) and experimentally (3). By a similar principle, the controlled directional motion on graphene was also explored by means of strain or wettability gradients (4-6). Carbon systems such as graphene and carbon nanotubes (CNTs) are prime candidate substrates (2, 3, 7-11) for these phoretic phenomena, owing to their remarkable mechanical strength and thermal conductivity. Computational studies have highlighted the possibility to drive thermally gold nanoparticles, water clusters, graphene nanoflakes, C60 clusters, and small CNTs over graphene layers or inside CNTs. Despite that, there appears to be so far insufficient intimate understanding of that phenomenon, besides the obvious consensus that the ...

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“…A similar problem has been investigated using DSMC or another kinetic approaches in [9][24]- [30]. In the following we shall consider the effects of Knudsen number and convection on heat transfer from the heated plate using finite difference numerical solutions of macroscopic methods.…”

Section: Introductionmentioning

confidence: 99%