We demonstrate how an exponentially saturating increase of the contact area between a nanoasperity and a crystal surface, occurring on time scales governed by the Arrhenius equation, is consistent with measurements of the static friction and lateral contact stiffness on a model alkali-halide surface at different temperatures in ultrahigh vacuum. The "contact ageing" effect is attributed to atom...

The friction between Al2O3 nanowires and silicon substrates of different surface textures was characterised by use of optical manipulation. It was found that surface textures had significant effect on both the friction and the effective contact area between a nanowire and a substrate. A genetic algorithm was developed to determine the effective contact area between the nanowire and the textured...

BACKGROUND/PURPOSE Friction blisters, a common injury in sports and military operations, can adversely effect or even halt performance. Given its frequency and hazardous nature, recent research efforts appear limited. Blistering can be treated as a delamination phenomenon; similar issues in materials science have been extensively investigated in theory and experiment. An obstacle in studying bl...

There have been many researches on object grasping in cooperating systems assuming no object slippage and stable grasp and the control system is designed to keep the contact force inside the friction cone to prevent the slippage. However undesired slippage can occur due to environmental conditions and many other reasons. In this research, dynamic analysis and control synthesis of a cooperating ...

To characterize the effect of shearing on function of fibrillar adhesive microstructure, friction and shear-related changes in pull-off force of a biomimetic polyvinylsiloxane mushroom-shaped fibrillar adhesive microstructure were studied. In contrast to a control flat surface, which exhibited pronounced stick-slip motion accompanied with high friction, the fibrillar microstructure demonstrated...

The friction between a single silica glass sphere and a flat silica glass surface has been investigated using lateral force microscopy. Two types of silica surface were investigated, one fully hydroxylated and the other partially dehydroxlated. These samples have markedly different wetting properties and are known as hydrophilic and hydrophobic silica, respectively. The lateral friction force a...

Sliding friction across a thin soft lubricant film typically occurs by stick slip, the lubricant fully solidifying at stick, yielding and flowing at slip. The static friction force per unit area preceding slip is known from molecular dynamics (MD) simulations to decrease with increasing contact area. That makes the large-size fate of stick slip unclear and unknown; its possible vanishing is imp...

Adhesion and friction are commonly observed to be correlated in many systems, particularly at the nanoscale where adhesion plays a substantial role. In this paper, we examine an unusual lack of correlation between nanoscale adhesion and friction. Diamond-like carbon (DLC) is a unique thin film material that can exhibit both low friction and high hardness via easy, low-cost deposition methods. W...

An artificial elastic finger for grasping an object, which we call an “artificial finger skin” is designed. Characteristics of the artificial finger skin are as follows: First, it has ridges at the surface and tactile sensors distributed underneath the ridges same as finger of human. Second, it has a curved surface in broad perspective. Third, it is made of an elastic silicone rubber so as to t...

Geckos owe their remarkable stickiness to millions of dry, hard setae on their toes. In this study, we discovered that gecko setae stick more strongly the faster they slide, and do not wear out after 30,000 cycles. This is surprising because friction between dry, hard, macroscopic materials typically decreases at the onset of sliding, and as velocity increases, friction continues to decrease be...