Noncontact friction via capillary shear interaction at nanoscale

Lee, Manhee; Kim, Bongsu; Kim, Jong-Woo; Jhe, Wonho

doi:10.1038/ncomms8359

Cited by 67 publications

(77 citation statements)

References 40 publications

(50 reference statements)

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“…All of the experiments were performed at room temperature (297.5 ± 1 K) and at a high relative humidity of 76.4 ± 2% where the capillary effects are negligible below 2 nm (28) (notice that the capillary effects, dominant beyond 2 nm separation, are fully described for the water nanomeniscus in ref. 27). Determination of the contact point is given in SI Appendix, section S5.…”

Section: Methodsmentioning

confidence: 99%

“…Notice that, above y 0 = 2 nm, the capillary effects dominate while the HWL effects disappear (28), and the nonlinear rheological properties due to capillarity are detailed in the ref. 27 (as shown in figure 3A of ref. 27, the contact line-induced interaction decreases k and b with the increase of A 0 ).…”

Section: Significancementioning

confidence: 99%

“…27, the contact line-induced interaction decreases k and b with the increase of A 0 ). Therefore, whereas the shear thickening of HWL originates from the fluctuation correlation, the capillary effect results in shear thinning, in contrast to HWL, associated with the pinning-depinning dynamics of the capillary contact line (27). Fig.…”

Section: Significancementioning

confidence: 99%

“…We find good agreement of experiment with theory when one incorporates the nonlinear fluidity due to correlated fluctuations between shear stress and strain rate. Interestingly, it turns out that shear thickening can be described by such a dominant rheological nonlinearity even in the presence of a noticeable change of the intrinsic viscosity of water (27).…”

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confidence: 99%

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Probing nonlinear rheology layer-by-layer in interfacial hydration water

Kim

Kwon

Lee

et al. 2015

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

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Viscoelastic fluids exhibit rheological nonlinearity at a high shear rate. Although typical nonlinear effects, shear thinning and shear thickening, have been usually understood by variation of intrinsic quantities such as viscosity, one still requires a better understanding of the microscopic origins, currently under debate, especially on the shear-thickening mechanism. We present accurate measurements of shear stress in the bound hydration water layer using noncontact dynamic force microscopy. We find shear thickening occurs above ∼ 10 6 s −1 shear rate beyond 0.3-nm layer thickness, which is attributed to the nonviscous, elasticityassociated fluidic instability via fluctuation correlation. Such a nonlinear fluidic transition is observed due to the long relaxation time (∼ 10 −6 s) of water available in the nanoconfined hydration layer, which indicates the onset of elastic turbulence at nanoscale, elucidating the interplay between relaxation and shear motion, which also indicates the onset of elastic turbulence at nanoscale above a universal shear velocity of ∼ 1 mm=s. This extensive layer-by-layer control paves the way for fundamental studies of nonlinear nanorheology and nanoscale hydrodynamics, as well as provides novel insights on viscoelastic dynamics of interfacial water.nonlinear rheology | hydration layer | shear thickening | elastic turbulence | dynamic force spectroscopy T he rheological nonlinearity of fluids (1-3) is a universal, highly nonequilibrium phenomenon observed in diverse systems ranging from soft materials [e.g., polymeric (1, 4), biological (5, 6), and colloidal (2, 7-9) solution] to terrestrial layers [e.g., Earth's mantle (10)], occurring at extremely high shear rates (1, 2, 11). Although shear thinning (decrease of viscosity) originates from the decrease of particle density correlation (2, 12), shear thickening (4, 7, 8, 13-17) (increase of viscosity) has been understood in various perspectives such as hydrodynamic instability (18) at high Reynolds number (Re) or order-disorder transition (13,14) at low Re and high Weissenberg number (Wi) [a measure of elasticity of viscoelastic flows (1); see SI Appendix, section S1, for nonlinear hydrodynamics formalism based on Re and Wi]. In particular, such a viscoelastic flow with low Re and high Wi exhibits behaviors similar to the inertial turbulence of Newtonian flow, so termed the elastic turbulence (4, 17). Despite extensive studies, however, one still lacks understanding of (i) the role of elastic instability in the enhanced flow resistance and (ii) the unexplored characteristics of nonlinear rheology at nanoscale.The hydration water layer (HWL), which is a ubiquitous form of nanoscale water consisting of water molecules tightly bound to ions or hydrophilic surfaces, is a highly viscoelastic fluid showing sluggish relaxation time (19-21) up to 10 μs (22). Better understanding of the HWL dynamics, especially its nonlinear rheology, is increasingly on demand to address diverse processes associated with HWL and to develop related technologies ...

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Section: Methodsmentioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Section: Significancementioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Probing nonlinear rheology layer-by-layer in interfacial hydration water

Kim

Kwon

Lee

et al. 2015

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

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“…There are many techniques for measuring surface forces, such as those involving the surface forces apparatus (SFA), atomic force microscopy (AFM), micro cantilever (MC), optical trapping (OT), etc. [13][14][15]. The SFA can directly measure the force between two surfaces in controlled vapors or immersed in liquids.…”

Section: Effect Of Relative Humidity On the Liquid Bridge Forcementioning

confidence: 99%

Reduction of Liquid Bridge Force for 3D Microstructure Measurements

et al. 2016

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Recent years have witnessed an increased demand for a method for precise measurement of the microstructures of mechanical microparts, microelectromechanical systems, micromolds, optical devices, microholes, etc. This paper presents a measurement system for three-dimensional (3D) microstructures that use an optical fiber probe. This probe consists of a stylus shaft with a diameter of 2.5 µm and a glass ball with a diameter of 5 µm attached to the stylus tip. In this study, the measurement system, placed in a vacuum vessel, is constructed suitably to prevent adhesion of the stylus tip to the measured surface caused by the surface force resulting from the van der Waals force, electrostatic force, and liquid bridge force. First, these surface forces are analyzed with the aim of investigating the causes of adhesion. Subsequently, the effects of pressure inside the vacuum vessel on surface forces are evaluated. As a result, it is found that the surface force is 0.13 µN when the pressure inside the vacuum vessel is 350 Pa. This effect is equivalent to a 60% reduction in the surface force in the atmosphere.

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The Role of Nanomechanics in Healthcare

Nautiyal

Alam

Balani

et al. 2017

Adv Healthcare Materials

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Nanomechanics has played a vital role in pushing our capability to detect, probe, and manipulate the biological species, such as proteins, cells, and tissues, paving way to a deeper knowledge and superior strategies for healthcare. Nanomechanical characterization techniques, such as atomic force microscopy, nanoindentation, nanotribology, optical tweezers, and other hybrid techniques have been utilized to understand the mechanics and kinetics of biospecies. Investigation of the mechanics of cells and tissues has provided critical information about mechanical characteristics of host body environments. This information has been utilized for developing biomimetic materials and structures for tissue engineering and artificial implants. This review summarizes nanomechanical characterization techniques and their potential applications in healthcare research. The principles and examples of label-free detection of cancers and myocardial infarction by nanomechanical cantilevers are discussed. The vital importance of nanomechanics in regenerative medicine is highlighted from the perspective of material selection and design for developing biocompatible scaffolds. This review interconnects the advancements made in fundamental materials science research and biomedical technology, and therefore provides scientific insight that is of common interest to the researchers working in different disciplines of healthcare science and technology.

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Noncontact friction via capillary shear interaction at nanoscale

Cited by 67 publications

References 40 publications

Probing nonlinear rheology layer-by-layer in interfacial hydration water

Probing nonlinear rheology layer-by-layer in interfacial hydration water

Reduction of Liquid Bridge Force for 3D Microstructure Measurements

The Role of Nanomechanics in Healthcare

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