An improved wedge calibration method for lateral force in atomic force microscopy

Varenberg, Michael; Etsion, I.; Halperin, G.

doi:10.1063/1.1584082

Cited by 382 publications

(354 citation statements)

References 17 publications

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“…All tests were carried out in air with a relative humidity (RH) of 50%-60% and room temperature of 20 °C -25 °C . After tests, friction forces were calibrated using a silicon grating with a wedge angle of 54°44' (TGF11, MikroMasch, Germany) [14]. To characterize the adhesive behavior of Si-SiO x /SiO 2 pair, the average adhesion forces F a were obtained by twenty pull-off tests.…”

Section: Methodsmentioning

confidence: 99%

Running-in process of Si-SiO x /SiO2 pair at nanoscale—Sharp drops in friction and wear rate during initial cycles

et al. 2013

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Abstract:Using an atomic force microscope, the running-in process of a single crystalline silicon wafer coated with native oxide layer (Si-SiO x ) against a SiO 2 microsphere was investigated under various normal loads and displacement amplitudes in ambient air. As the number of sliding cycles increased, both the friction force F t of the Si-SiO x /SiO 2 pair and the wear rate of the silicon surface showed sharp drops during the initial 50 cycles and then leveled off in the remaining cycles. The sharp drop in F t appeared to be induced mainly by the reduction of adhesion-related interfacial force between the Si-SiO x /SiO 2 pair. During the running-in process, the contact area of the Si-SiO x /SiO 2 pair might become hydrophobic due to removal of the hydrophilic oxide layer on the silicon surface and the surface change of the SiO 2 tip, which caused the reduction of friction force and the wear rate of the Si-SiO x /SiO 2 pair. A phenomenological model is proposed to explain the running-in process of the Si-SiO x /SiO 2 pair in ambient air. The results may help us understand the mechanism of the running-in process of the Si-SiO x /SiO 2 pair at nanoscale and reduce wear failure in dynamic microelectromechanical systems (MEMS).

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Section: Methodsmentioning

confidence: 99%

Running-in process of Si-SiO x /SiO2 pair at nanoscale—Sharp drops in friction and wear rate during initial cycles

et al. 2013

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“…Therefore, it is reduced to calibrating the three force constants, ␣ n , ␣ ll , and ␣ ln , for complete characterization of the mechanical responses of the AFM cantilever-tip assembly. When m =0 and * = 0, as a special case, ␣ ln vanishes and ␣ ll reduces to the calibration constant ␣ used by Varenberg et al 7 Except for special slope tests such as employed in W-LFC, 4 AFM friction tests are generally carried out with the substrate angle * = 0, for which the transformation matrix in ͑8͒ becomes the identity matrix and the force components in the sensing coordinates are identical to the components in the friction coordinates, i.e., f = f and N = N . In a typical AFM friction experiment with * = 0, a friction loop composed of forward sliding and backward sliding processes, under constant normal load, is used to get rid of the effect of the crosstalk force constant ␣ ln in ͑9a͒.…”

Section: A Deformation and Transducer Characteristics Of An Afm Fricmentioning

confidence: 99%

“…It is noticed that our definition of ␤ l gives the relationship ␤ l = / ␤, with the calibration constant ␤ used by Varenberg et al 7 Denoting the substrate angle between x and x as * , and the shear center misfit angle between OC and ŷ as m , we have the relationship 0 = *− m , and ͑3͒ can be expanded to…”

Section: A Deformation and Transducer Characteristics Of An Afm Fricmentioning

confidence: 99%

“…So far, any existing technique for calibrating the force constants could either be characterized as an indirect method of calibration [8][9][10][11][12] or as a semidirect method of calibration. 4,7 The wedge method 4 is one such semidirect calibration method, because we have to evaluate separately some geometric variables, in general, for 0, although we do not have to assess the torsional spring constant and the angle sensitivity constant individually. In this section we will discuss some difficulties and limitations in calibrating the force constants with existing methods.…”

Section: B Difficulties and Limitations In Existing Calibration Techmentioning

confidence: 99%

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Lateral force calibration of an atomic force microscope with a diamagnetic levitation spring system

Kim

Rydberg

2006

Review of Scientific Instruments

176

127

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A novel diamagnetic lateral force calibrator (D-LFC) has been developed to directly calibrate atomic force microscope (AFM) cantilever-tip or -bead assemblies. This enables an AFM to accurately measure the lateral forces encountered in friction or biomechanical-testing experiments at a small length scale. In the process of development, deformation characteristics of the AFM cantilever assemblies under frictional loading have been analyzed and four essential response variables, i.e., force constants, of the assembly have been identified. Calibration of the lateral force constant and the “crosstalk” lateral force constant, among the four, provides the capability of measuring absolute AFM lateral forces. The D-LFC is composed of four NdFeB magnets and a diamagnetic pyrolytic graphite sheet, which can calibrate the two constants with an accuracy on the order of 0.1%. Preparation of the D-LFC and the data processing required to get the force constants is significantly simpler than any other calibration methods. The most up-to-date calibration technique, known as the “wedge method,” calibrates mainly one of the two constants and, if the crosstalk effect is properly analyzed, is primarily applicable to a sharp tip. In contrast, the D-LFC can calibrate both constants simultaneously for AFM tips or beads with any radius of curvature. These capabilities can extend the applicability of AFM lateral force measurement to studies of anisotropic multiscale friction processes and biomechanical behavior of cells and molecules under combined loading. Details of the D-LFC method as well as a comparison with the wedge method are provided in this article.

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“…The optical lever sensitivity of each modified cantilevers was calibrated in DI water before each set of experiments. The friction force was acquired by converting the lateral signal collected by the photodetector from voltage to newton using the wedge method [54,55], where the cantilever is scanned across a calibration grating (TGF11, MikroMasch, Tallinn, Estonia) and the frictional signal is measured as a function of applied load.…”

Section: Friction Force Microscopymentioning

confidence: 99%

Salt Dependence of the Tribological Properties of a Surface-Grafted Weak Polycation in Aqueous Solution

et al. 2017

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The nanoscopic adhesive and frictional behaviour of end-grafted poly[2-(dimethyl amino)ethyl methacrylate] (PDMAEMA) films (brushes) in contact with gold-or PDMAEMA-coated atomic force microscope tips in potassium halide solutions with different concentrations up to 300 mM is a strong function of salt concentration. The conformation of the polymers in the brush layer is sensitive to salt concentration, which leads to large changes in adhesive forces and the contact mechanics at the tip-sample contact, with swollen brushes (which occur at low salt concentrations) yielding large areas of contact and friction-load plots that fit JKR behaviour, while collapsed brushes (which occur at high salt concentrations) yield sliding dominated by ploughing, with conformations in between fitting DMT mechanics. The relative effect of the different anions follows the Hofmeister series, with I − collapsing the brushes more than Br − and Cl − for the same salt concentration.

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An improved wedge calibration method for lateral force in atomic force microscopy

Cited by 382 publications

References 17 publications

Running-in process of Si-SiO x /SiO2 pair at nanoscale—Sharp drops in friction and wear rate during initial cycles

Running-in process of Si-SiO x /SiO2 pair at nanoscale—Sharp drops in friction and wear rate during initial cycles

Lateral force calibration of an atomic force microscope with a diamagnetic levitation spring system

Salt Dependence of the Tribological Properties of a Surface-Grafted Weak Polycation in Aqueous Solution

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