Friction and Molecular Deformation in the Tensile Regime

Simultaneous measurement of normal and friction forces using a cantilever-based optical interfacial force microscope

“…The previous technique of measuring friction employed a lateral modulation of the sample relative to the cantilever as a means to measure normal force and friction force at the same time [7][8][9][10][11]13 . However, the technique can only be applied to the measurement of friction while the tip is touching because of an intrinsic mechanical instability of the tip-sample assembly called the snap-to-contact problem.…”

Directional shear force microscopy

“…The shear forces experienced at the tip of the laterally oscillating fiber have been shown to be an effective way to study fundamental aspects of friction. 9,10 In this letter, we show that by virtue of the lateral orientation of the oscillating fiber, directional shear force microscopy can be used to reveal friction anisotropy, independent of scan direction.…”

“…Simultaneous normal force sensing has also been demonstrated. 9,10 We acknowledge help from S. Stranick …”

Cantilever-Based Optical Interfacial Force Microscopy

“…As an approach to study attractive regimes, friction forces have been measured using the IFM (Joyce & Houston, 1991), where the force feedback makes it possible. (Burns et al, 1999a;Goertz et al, 2007;Major et al, 2006). Burns et al applied IFM to measure friction force and normal force simultaneously to study the molecular nature of friction to investigate the intermolecular friction along with normal forces in the attractive regime (Burns et al, 1999a).…”

“…Kim et al, 2001;Major et al, 2006). These previous techniques of measuring friction employed a lateral modulation of the sample relative to the cantilever as a means to measure normal force and friction force at the same time (Burns et al, 1999a;Carpick et al, 1997;Colchero et al, 1996;Goddenhenrich et al, 1994;Goertz et al, 2007;Major et al, 2006). However, AFM usage has been limited to passive applications (e.g., pull-off force measurement in the force-distance curve) and can only be applied to the measurement of friction while the tip is touching the sample surface because of an intrinsic mechanical instability of the tip-sample assembly near a sample surface called the "snap-to-contact problem" (Burnham, 1989;Lodge, 1983).…”