Contact area

About: Contact area is a research topic. Over the lifetime, 12358 publications have been published within this topic receiving 256401 citations. The topic is also known as: contact patch & contact region.

Silver nanoparticles deposited on dielectric surfaces

Abstract: Surface plasmon polaritons in nanoparticles were used as a sensitive indicator of structural and electronic properties of metallic nanoparticles deposited upon various dielectric substrates. Quantum size and cluster–substrate interactions were separated. The latter were modelled with the dynamic charge transfer effect. For calibration purposes, the free surfaces of the same clusters exposed to a UHV beam were also investigated. The particles were slightly deformed during deposition; their final shapes and, in particular, their contact areas were determined. The width of the plasmon excitation band was roughly doubled compared to that of the free particles, but proved to depend only slightly on the chemical nature of the substrates, in drastic contrast to the case of fully embedded particles. The analogy holds for the dephasing lifetimes. One reason for this is that the contact area varies strongly with the substrate material, while it is constant in systems of matrix-embedded particles.

Observation of proportionality between friction and contact area at the nanometer scale

Abstract: The nanotribological properties of a hydrogen‐terminated diamond(111)/tungsten‐carbide interface have been studied using ultra‐high vacuum atomic force microscopy. Both friction and local contact conductance were measured as a function of applied load. The contact conductance experiments provide a direct and independent way of determining the contact area between the conductive tungsten‐carbide AFM tip and the doped diamond sample. We demonstrate that the friction force is directly proportional to the real area of contact at the nanometer‐scale. Furthermore, the relation between the contact area and load for this extremely hard heterocontact is found to be in excellent agreement with the Derjaguin–Muller–Toporov continuum mechanics model.

An investigation of microscopic aspects of contact angle hysteresis: pinning of the contact line on a single defect

Abstract: We examine the microscopic pinning of a contact line on a single heterogeneity. We find that many features of this behavior are predicted by models based on the same energy functionals which describe macroscopic contact angle hysteresis on surfaces with many such imperfections. As the defect emerges from the undistorted contact line, the contact line pins, increasingly distorts, slides across the defect, and then jumps back to an undistorted position. The distortion of a stably pinned contact line is described by a logarithmic dependence. While the force pinning the contact line depends on the defect microstructure, the elastic restoring force follows Hooke's law and is dependent on the properties of the fluid and contact angle on the underlying surface. The sliding motion and unstable jumps of the contact line occur at small capillary numbers.

A comparison of contact modeling utilizing statistical and fractal approaches

Abstract: Statistical and fractal approaches for characterizing surface topography have been used widely in contact mechanics. In the present study, a comparison is conducted between contact mechanics results obtained with statistical and fractal approaches to characterize surface topography. Specifically, a three-dimensional fractal surface was generated and statistical surface parameters were extracted using different sampling resolutions. Contact mechanics simulations were performed using the simulated fractal surface and statistical surfaces represented by the extracted statistical surface parameters. Purely elastic contact (Hertz) is studied in order to eliminate any possible influence of the individual asperity mechanical response on the obtained results. Therefore, differences in the simulated contact area and load can be related solely to the different approach employed for surface characterization.